test(docs): refresh core API baseline after main merge

Fix `findFormValue` so dotted strings supplied as direct or dotted-key parameters remain literal instead of being discarded as path references. Preserve the existing lookup order, clarify flat-key and slash-path state lookup behavior, and add coverage for dotted emails, URLs, versions, and `$state`-resolved action parameters.

Factory-Run: 4f2d892359c9c4abf2a5bad40b415802

Co-authored-by: Chris Tate <366502+ctate@users.noreply.github.com>
Co-authored-by: kevin <5299031+kevin9327@users.noreply.github.com>

.changeset/README.md

@@ -1,13 +0,0 @@
-# Changesets
-
-Hello and welcome! This folder has been automatically generated by `@changesets/cli`, a build tool that works
-with multi-package repos, or single-package repos to help you version and publish your code. You can
-find the full documentation for it [in the repository](https://github.com/changesets/changesets).
-
-## Adding a changeset
-
-To add a changeset, run `pnpm changeset` in the root of the repository. This will prompt you to select
-which packages have changed and what type of version bump (major, minor, or patch) should be applied.
-
-All `@json-render/*` packages are versioned together -- a changeset for any one of them will bump all
-packages to the same version.

.changeset/config.json

@@ -1,39 +0,0 @@
-{
-  "$schema": "https://unpkg.com/@changesets/config@3.1.1/schema.json",
-  "changelog": "@changesets/cli/changelog",
-  "commit": false,
-  "fixed": [
-    [
-      "@json-render/core",
-      "@json-render/react",
-      "@json-render/react-email",
-      "@json-render/react-pdf",
-      "@json-render/shadcn",
-      "@json-render/react-native",
-      "@json-render/remotion",
-      "@json-render/codegen",
-      "@json-render/zustand",
-      "@json-render/redux",
-      "@json-render/jotai",
-      "@json-render/vue",
-      "@json-render/xstate",
-      "@json-render/image",
-      "@json-render/mcp",
-      "@json-render/svelte",
-      "@json-render/solid",
-      "@json-render/react-three-fiber",
-      "@json-render/yaml",
-      "@json-render/shadcn-svelte",
-      "@json-render/ink",
-      "@json-render/next"
-    ]
-  ],
-  "linked": [],
-  "access": "public",
-  "baseBranch": "main",
-  "updateInternalDependencies": "patch",
-  "privatePackages": {
-    "version": true,
-    "tag": false
-  }
-}

.github/workflows/ci.yml

@@ -13,6 +13,18 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  version-sync:
+    name: Version Sync Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+      - name: Check version sync
+        run: node scripts/check-version-sync.js
+
   lint:
     name: Lint
     runs-on: ubuntu-latest
@@ -21,7 +33,7 @@ jobs:
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version-file: .node-version
           cache: pnpm
       - run: pnpm install --frozen-lockfile
       - run: pnpm lint
@@ -34,13 +46,34 @@ jobs:
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version-file: .node-version
           cache: pnpm
       - run: pnpm install --frozen-lockfile
       - name: Build packages
         run: pnpm turbo run build --filter='./packages/*'
       - run: pnpm test
 
+  docs:
+    name: Docs (${{ matrix.environment }})
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        environment: [production, preview]
+    env:
+      VERCEL_ENV: ${{ matrix.environment }}
+      DOCS_EXPECT_NOINDEX: ${{ matrix.environment == 'preview' && '1' || '0' }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm turbo run build --filter='web^...'
+      - run: pnpm --filter web build
+      - run: pnpm --filter web test:routes
+
   typecheck:
     name: Type Check
     runs-on: ubuntu-latest
@@ -49,7 +82,7 @@ jobs:
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version-file: .node-version
           cache: pnpm
       - run: pnpm install --frozen-lockfile
       - run: pnpm type-check

.github/workflows/release.yml

@@ -6,21 +6,74 @@ on:
       - main
   workflow_dispatch:
 
-concurrency: ${{ github.workflow }}-${{ github.ref }}
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: false
 
 permissions:
-  contents: write
-  pull-requests: write
+  contents: read
 
 jobs:
-  release:
-    name: Release
+  check-release:
+    name: Check for new version
     runs-on: ubuntu-latest
+    timeout-minutes: 5
+    outputs:
+      should_release: ${{ steps.check.outputs.should_release }}
+      needs_github_release: ${{ steps.check.outputs.needs_github_release }}
+      version: ${{ steps.check.outputs.version }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
         with:
-          fetch-depth: 0
+          node-version-file: .node-version
+
+      - name: Compare package.json version to npm and check GitHub release
+        id: check
+        run: |
+          LOCAL_VERSION=$(node -p "require('./packages/core/package.json').version")
+          echo "Local version: $LOCAL_VERSION"
+
+          NPM_VERSION=$(npm view @json-render/core version 2>/dev/null || echo "0.0.0")
+          echo "npm version: $NPM_VERSION"
+
+          if [ "$LOCAL_VERSION" != "$NPM_VERSION" ]; then
+            echo "Version changed: $NPM_VERSION -> $LOCAL_VERSION"
+            echo "should_release=true" >> "$GITHUB_OUTPUT"
+            echo "needs_github_release=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "Version unchanged on npm, skipping build and publish"
+            echo "should_release=false" >> "$GITHUB_OUTPUT"
+
+            TAG="v$LOCAL_VERSION"
+            if gh release view "$TAG" &>/dev/null; then
+              echo "GitHub release $TAG exists"
+              echo "needs_github_release=false" >> "$GITHUB_OUTPUT"
+            else
+              echo "GitHub release $TAG is missing, will create it"
+              echo "needs_github_release=true" >> "$GITHUB_OUTPUT"
+            fi
+          fi
+          echo "version=$LOCAL_VERSION" >> "$GITHUB_OUTPUT"
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  publish:
+    name: Publish to npm
+    needs: check-release
+    if: needs.check-release.outputs.should_release == 'true'
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    environment: Release
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4
@@ -28,20 +81,86 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version-file: .node-version
           cache: pnpm
           registry-url: "https://registry.npmjs.org"
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
-      - name: Create Release Pull Request or Publish
-        uses: changesets/action@v1
-        with:
-          version: pnpm ci:version
-          publish: pnpm ci:publish
-          title: "chore: version packages"
-          commit: "chore: version packages"
+      - name: Build packages
+        run: pnpm run build
+
+      - name: Publish all public packages
+        run: |
+          LOCAL_VERSION="${{ needs.check-release.outputs.version }}"
+          FAILED=""
+
+          publish_pkg() {
+            local dir="$1" name="$2"
+            REGISTRY_VERSION=$(npm view "$name" version 2>/dev/null || echo "0.0.0")
+            if [ "$LOCAL_VERSION" = "$REGISTRY_VERSION" ]; then
+              echo "$name@$LOCAL_VERSION already published, skipping"
+              return 0
+            fi
+            echo "Publishing $name@$LOCAL_VERSION..."
+            TARBALL=$(cd "$dir" && pnpm pack --pack-destination /tmp | tail -1)
+            if ! npm publish "$TARBALL" --provenance --access public; then
+              FAILED="$FAILED $name"
+            fi
+          }
+
+          for dir in packages/*/; do
+            PKG_NAME=$(node -p "try { const p = require('./$dir/package.json'); p.private ? '' : p.name } catch { '' }")
+            [ -z "$PKG_NAME" ] && continue
+            publish_pkg "$dir" "$PKG_NAME"
+          done
+
+          if [ -n "$FAILED" ]; then
+            echo "Failed to publish:$FAILED"
+            exit 1
+          fi
+
+  github-release:
+    name: Create GitHub Release
+    needs: [check-release, publish]
+    if: >-
+      always()
+      && needs.check-release.outputs.needs_github_release == 'true'
+      && (needs.publish.result == 'success' || needs.publish.result == 'skipped')
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Extract changelog entry
+        run: |
+          VERSION="${{ needs.check-release.outputs.version }}"
+          awk '/<!-- release:start -->/{found=1; next} /<!-- release:end -->/{found=0} found{print}' CHANGELOG.md > /tmp/release-notes.md
+
+          LINES=$(wc -l < /tmp/release-notes.md | tr -d ' ')
+          if [ "$LINES" -lt 2 ]; then
+            echo "Error: No release notes found between <!-- release:start --> and <!-- release:end --> markers in CHANGELOG.md"
+            exit 1
+          fi
+          echo "Extracted release notes for $VERSION ($LINES lines)"
+
+      - name: Create GitHub Release
+        run: |
+          VERSION="${{ needs.check-release.outputs.version }}"
+          TAG="v$VERSION"
+
+          if gh release view "$TAG" &>/dev/null; then
+            echo "Release $TAG already exists"
+          else
+            echo "Creating release $TAG..."
+            gh release create "$TAG" \
+              --title "$TAG" \
+              --target ${{ github.sha }} \
+              --notes-file /tmp/release-notes.md
+          fi
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_VERCEL_TOKEN_ELEVATED }}

.gitignore

@@ -29,6 +29,8 @@ build
 dist
 *.tsbuildinfo
 .svelte-kit/
+tsup.config.bundled_*.mjs
+next-env.d.ts
 
 
 # Debug

.node-version

@@ -0,0 +1 @@
+24

AGENTS.md

@@ -66,6 +66,8 @@ Do **not** add `--port` flags -- portless handles port assignment automatically.
 ## Workflow
 
 - Run `pnpm type-check` after each turn to ensure type safety
+- Documentation lives in `apps/web/content/docs/` and uses Geistdocs frontmatter. Keep public `/docs` URLs, heading IDs, `lib/page-titles.ts`, `lib/docs-navigation.ts`, and the content `meta.json` files in sync.
+- For docs routing or infrastructure changes, run `pnpm turbo run build --filter='web^...'`, `pnpm --filter web build`, and `pnpm --filter web test:routes`. Existing-page source and Markdown parity are covered by `apps/web/tests/fixtures/docs-baseline.json`; update fixtures only when intentionally changing the documented content.
 - When making user-facing changes (new packages, API changes, new features, renamed exports, changed behavior), update the relevant documentation:
   - Package `README.md` files in `packages/*/README.md`
   - Root `README.md` (if packages table, install commands, or examples are affected)
@@ -73,40 +75,38 @@ Do **not** add `--port` flags -- portless handles port assignment automatically.
   - Skills in `skills/*/SKILL.md` (if the package has a corresponding skill)
   - `AGENTS.md` (if workflow or conventions change)
 
-## Releases
+## Releasing
 
-This monorepo uses [Changesets](https://github.com/changesets/changesets) for versioning and publishing.
+Releases are manual, single-PR affairs. The maintainer controls the changelog voice and format.
 
-### Fixed version group
-
-All public `@json-render/*` packages are in a **fixed** group (see `.changeset/config.json`). A changeset that bumps any one of them bumps all of them to the same version. You only need to list the packages that actually changed in the changeset front matter — the fixed group handles the rest.
+All public `@json-render/*` packages share the same version. The canonical version lives in `packages/core/package.json`.
 
 ### Preparing a release
 
-When asked to prepare a release (e.g. "prepare v0.12.0"):
+When asked to prepare a release (e.g. "prepare v0.17.0"):
 
-1. **Create a changeset file** at `.changeset/v0-<N>-release.md` following the existing pattern:
-   - YAML front matter listing changed packages with bump type (`minor` for feature releases, `patch` for bug-fix-only releases)
-   - A one-line summary, then `### New:` / `### Improved:` / `### Fixed:` sections describing each change
-   - Always list `@json-render/core` plus any packages with actual code changes
-2. **Do NOT bump versions** in `package.json` files — CI runs `pnpm ci:version` (which calls `changeset version`) to do that automatically
-3. **Do NOT manually write `CHANGELOG.md`** entries — `changeset version` generates them from the changeset file
-4. **Add new packages to the fixed group** in `.changeset/config.json` if they should be versioned together with the rest
+1. Create a branch (e.g. `prepare-v0.17.0`)
+2. Bump the version in `packages/core/package.json`
+3. Run `pnpm run version:sync` to update all other `@json-render/*` packages
+4. Write the changelog entry in `CHANGELOG.md`, wrapped in `<!-- release:start -->` and `<!-- release:end -->` markers (move the markers from the previous entry to the new one)
 5. **Fill documentation gaps** — every public package should have:
    - A row in the root `README.md` packages table
    - A renderer section in the root `README.md` (if it's a renderer)
-   - An API reference page at `apps/web/app/(main)/docs/api/<name>/page.mdx`
+   - An API reference page at `apps/web/content/docs/api/<name>.mdx`
    - An entry in `apps/web/lib/page-titles.ts` and `apps/web/lib/docs-navigation.ts`
    - An entry in the docs-chat system prompt (`apps/web/app/api/docs-chat/route.ts`)
    - A skill at `skills/<name>/SKILL.md`
    - A `packages/<name>/README.md`
 6. **Run `pnpm type-check`** after all changes to verify nothing is broken
+7. Open a PR and merge to `main`
 
-### CI scripts
+CI compares the `@json-render/core` version to what's on npm. If it differs, it builds, publishes all public packages, and creates the GitHub release automatically. The release body is extracted from the content between the markers.
 
-- `pnpm changeset` — interactively create a new changeset
-- `pnpm ci:version` — run `changeset version` + lockfile update (CI only)
-- `pnpm ci:publish` — build all packages and publish to npm (CI only)
+### Scripts
+
+- `pnpm run version:sync` — sync all `@json-render/*` package versions to match `@json-render/core`
+- `pnpm run version:check` — verify all versions are in sync (runs in CI)
+- `pnpm run ci:publish` — build all packages and publish to npm (CI only)
 
 <!-- opensrc:start -->
 

CHANGELOG.md

@@ -0,0 +1,110 @@
+# Changelog
+
+## 0.21.0
+
+<!-- release:start -->
+
+### New Features
+
+- **TanStack Start renderer:** Added `@json-render/tanstack-start` for JSON-defined applications with file-based routes, reusable layouts, SSR loaders, head metadata, prerender paths, client navigation, and route fallbacks (#334)
+- **Experimental Jev composition:** Added `experimental_composeSpec` and `experimental_createEvaluator` to compose validated specs from app-owned candidates, plus a Jev model option and iterative composition editing in the playground
+
+### Improvements
+
+- **Vue named slots:** Vue registries now support catalog-declared named slots alongside the default `children` slot (#323)
+- **React streaming stability:** Stabilized streamed React renders and added coverage for incomplete streamed props and nested prop identities (#325)
+- **Documentation and project status:** Expanded renderer, Jev, and package documentation and added Labs status badges to the project README
+
+### Contributors
+
+- @ctate
+- @Railly
+<!-- release:end -->
+
+## 0.20.0
+
+### New Features
+
+- **Named slots for React:** Components can declare named slots such as `header` and `footer`, while `children` remains the default slot. Slots are preserved through validation, streaming, nested conversion, code export, playground views, and Devtools navigation (#320). Built from the original contribution by @wotnak in #105
+- **Nested repeats:** `repeat.statePath` now accepts item-relative paths such as `{ "$item": "employees" }`, enabling nested data rendering across React, React Native, React Email, React PDF, Image, Ink, Solid, Svelte, and Vue (#319). Built from the original contribution by @tmchow in #256
+- **Harness chat example:** Added a complete Next.js example using the AI SDK 7 harness adapter, agent delegation, sandbox transport, and json-render components (#302)
+
+### Bug Fixes
+
+- **Chained action params:** Named `onSuccess` and `onError` actions now receive their configured `params` across core and all renderer bridges (#307)
+- **Consistent optional visibility:** Element `visible` fields now remain optional across Zod 4 versions, while prompts explicitly require `children` arrays for every element (#299)
+- **Spec validation and autofix:** Dangling child references are pruned, malformed visibility conditions are reported, and repeated items can be filtered safely (#300)
+
+### Improvements
+
+- **Release toolchain hardening:** The workspace now requires Node.js 24 and pnpm 11, enforces package engine checks, and applies a minimum package release age (#293)
+
+### Breaking Changes
+
+- Custom renderer bridges that implement the core `executeAction` callback must now accept an `ActionBinding` instead of a bare action name. This exposes chained action params to custom integrations at compile time (#307)
+
+### Contributors
+
+- @ctate
+- @Railly
+- @tmchow
+- @wotnak
+
+## 0.19.0
+
+### New Features
+
+- **Custom directives API** — `@json-render/core` now supports custom directives via `defineDirective`, letting you declare new JSON shapes (like `$format`, `$math`) that resolve to computed values at render time. Directives compose naturally — nest `$format` over `$math` over `$state` and they resolve inside-out. All four renderers (React, Vue, Svelte, Solid) have built-in directive resolution (#279)
+- **`@json-render/directives`** — New package shipping seven ready-made directives: `$format` (date, currency, number, percent via `Intl`), `$math` (add, subtract, multiply, divide, mod, min, max, round, floor, ceil, abs), `$concat`, `$count`, `$truncate`, `$pluralize`, and `$join`. Also exports `createI18nDirective` for `$t` translation keys with `{{param}}` interpolation, and `standardDirectives` for one-line registration (#279)
+
+### Improvements
+
+- **Example READMEs** — Added documentation to the chat, dashboard, game-engine, and no-ai examples (#277)
+
+### Contributors
+
+- @ctate
+
+## 0.18.0
+
+### New Features
+
+- **Devtools** — Five new packages for inspecting json-render apps in the browser: `@json-render/devtools` (framework-agnostic core), plus `@json-render/devtools-react`, `@json-render/devtools-vue`, `@json-render/devtools-svelte`, and `@json-render/devtools-solid` adapters. Drop `<JsonRenderDevtools />` into your app to get a shadow-DOM-isolated panel with six tabs (Spec, State, Actions, Stream, Catalog, Pick), a DOM picker that maps clicked elements back to spec keys via `data-jr-key`, a capped event store, and server-side stream tap utilities. Floating toggle or `Cmd`/`Ctrl` + `Shift` + `J`, tree-shakes to `null` in production (#273)
+- **Devtools example** — New `examples/devtools` Next.js demo showing the full devtools panel wired up to an AI chat endpoint and a component catalog (#273)
+- **Action observer and devtools flag in core** — `@json-render/core` now exposes an action observer and a devtools enablement flag that adapters use to mirror actions and stream events into the panel (#273)
+
+### Bug Fixes
+
+- **Zod 4 schema formatting** — `formatZodType` now correctly handles `z.record()`, `z.default()`, and `z.literal()` types from Zod 4, which previously produced incorrect or empty output in generated prompts and schemas (#239)
+
+### Improvements
+
+- **Zod 4 test coverage** — Added unit tests for `formatZodType` covering record, default, and literal types to guard against regressions (#272)
+
+### Contributors
+
+- @ctate
+- @mvanhorn
+
+## 0.17.0
+
+### New Features
+
+- **Gaussian Splatting** — Added `GaussianSplat` component to `@json-render/react-three-fiber`, bringing the component count to 20. Composable with all existing R3F components (lights, controls, post-processing) via drei's Splat loader (#259)
+- **Standalone gsplat example** — Experimental demo app showcasing Gaussian Splatting with gsplat.js (no Three.js dependency), featuring scene selector, live JSON spec viewer, and progress indicator (#259)
+- **R3F gsplat example** — Demo app with five scenes: splat showroom, splat with primitives, multi-splat, post-processing effects, and animated floating splat (#259)
+
+### Improved
+
+- **AI output quality** — Improved prompt output and schema generation for more reliable AI-generated specs (#268)
+
+### Contributors
+
+- @ctate
+- @willmanzoli
+
+## 0.16.0
+
+### Improved
+
+- **Release process** — Switched from Changesets to a manual single-PR release workflow with changelog markers and automatic npm publish on version bump

README.md

@@ -4,6 +4,13 @@
 
 Generate dynamic, personalized UIs from prompts without sacrificing reliability. Predefined components and actions for safe, predictable output.
 
+<p>
+  <a href="https://vercel.com/labs#labs-products"><img alt="Vercel Labs Product" src="https://img.shields.io/badge/LABS-PRODUCT-0a0a0a.svg?style=for-the-badge&amp;logo=Vercel&amp;labelColor=000000" height="28"></a>
+  <a href="https://www.npmjs.com/package/@json-render/core"><img alt="npm version: @json-render/core" src="https://img.shields.io/npm/v/%40json-render%2Fcore.svg?style=for-the-badge&amp;labelColor=000000" height="28"></a>
+  <a href="https://github.com/vercel-labs/json-render/blob/main/LICENSE"><img alt="License: Apache-2.0" src="https://img.shields.io/github/license/vercel-labs/json-render.svg?style=for-the-badge&amp;labelColor=000000" height="28"></a>
+  <a href="https://www.npmjs.com/package/@json-render/core"><img alt="npm downloads per month: @json-render/core" src="https://img.shields.io/npm/dm/%40json-render%2Fcore.svg?style=for-the-badge&amp;labelColor=000000&amp;label=npm%20downloads" height="28"></a>
+</p>
+
 ```bash
 # for React
 npm install @json-render/core @json-render/react
@@ -27,7 +34,7 @@ npm install @json-render/core @json-render/solid
 npm install @json-render/core @json-render/ink ink react
 # or for full Next.js apps (routes, layouts, SSR, metadata)
 npm install @json-render/core @json-render/react @json-render/next
-# or for 3D scenes
+# or for 3D scenes (and gaussian splatting via the GaussianSplat component)
 npm install @json-render/core @json-render/react-three-fiber @react-three/fiber @react-three/drei three
 ```
 
@@ -128,15 +135,22 @@ function Dashboard({ spec }) {
 | `@json-render/solid`        | SolidJS renderer with fine-grained reactive contexts                   |
 | `@json-render/shadcn`       | 36 pre-built shadcn/ui components (Radix UI + Tailwind CSS)            |
 | `@json-render/shadcn-svelte`| 36 pre-built shadcn-svelte components (Svelte 5 + Tailwind CSS)        |
-| `@json-render/react-three-fiber` | React Three Fiber renderer for 3D scenes (19 built-in components)  |
+| `@json-render/react-three-fiber` | React Three Fiber renderer for 3D scenes (20 built-in components, including GaussianSplat)  |
 | `@json-render/react-native` | React Native renderer with standard mobile components                  |
 | `@json-render/next`         | Next.js renderer — JSON becomes full apps with routes, layouts, SSR    |
+| `@json-render/tanstack-start` | TanStack Start renderer — full apps with routes, layouts, SSR, and head metadata |
 | `@json-render/remotion`     | Remotion video renderer, timeline schema                               |
 | `@json-render/react-pdf`    | React PDF renderer for generating PDF documents from specs             |
 | `@json-render/react-email`  | React Email renderer for HTML/plain-text emails from specs             |
 | `@json-render/ink`          | Ink terminal renderer with built-in components for interactive TUIs.   |
 | `@json-render/image`        | Image renderer for SVG/PNG output (OG images, social cards) via Satori |
+| `@json-render/directives`   | Pre-built custom directives — $format, $math, $concat, $count, $truncate, $pluralize, $join, $t (i18n) |
 | `@json-render/codegen`      | Utilities for generating code from json-render UI trees                |
+| `@json-render/devtools`     | Framework-agnostic devtools core — panel UI, event store, picker, stream taps |
+| `@json-render/devtools-react`   | React adapter for `@json-render/devtools` (drop-in `<JsonRenderDevtools />`)     |
+| `@json-render/devtools-vue`     | Vue adapter for `@json-render/devtools`                                           |
+| `@json-render/devtools-svelte`  | Svelte adapter for `@json-render/devtools`                                        |
+| `@json-render/devtools-solid`   | SolidJS adapter for `@json-render/devtools`                                       |
 | `@json-render/redux`        | Redux / Redux Toolkit adapter for `StateStore`                         |
 | `@json-render/zustand`      | Zustand adapter for `StateStore`                                       |
 | `@json-render/jotai`        | Jotai adapter for `StateStore`                                         |
@@ -462,6 +476,7 @@ const catalog = defineCatalog(schema, {
     Sphere: threeComponentDefinitions.Sphere,
     AmbientLight: threeComponentDefinitions.AmbientLight,
     DirectionalLight: threeComponentDefinitions.DirectionalLight,
+    GaussianSplat: threeComponentDefinitions.GaussianSplat,
     OrbitControls: threeComponentDefinitions.OrbitControls,
   },
   actions: {},
@@ -473,6 +488,7 @@ const { registry } = defineRegistry(catalog, {
     Sphere: threeComponents.Sphere,
     AmbientLight: threeComponents.AmbientLight,
     DirectionalLight: threeComponents.DirectionalLight,
+    GaussianSplat: threeComponents.GaussianSplat,
     OrbitControls: threeComponents.OrbitControls,
   },
 });
@@ -528,6 +544,54 @@ const app = createNextApp({ spec });
 // </NextAppProvider>
 ```
 
+### TanStack Start (Full Apps)
+
+```tsx
+import { createFileRoute, notFound } from "@tanstack/react-router";
+import {
+  PageRenderer,
+  StartErrorBoundary,
+  StartLoading,
+  StartNotFound,
+  type StartAppSpec,
+} from "@json-render/tanstack-start";
+import { createStartApp } from "@json-render/tanstack-start/server";
+
+const spec: StartAppSpec = {
+  metadata: { title: { default: "My App", template: "%s | My App" } },
+  routes: {
+    "/": {
+      metadata: { title: "Home" },
+      page: {
+        root: "hero",
+        elements: {
+          hero: { type: "Card", props: { title: "Welcome" }, children: [] },
+        },
+      },
+    },
+  },
+};
+
+const { getPageData, getHead } = createStartApp({ spec });
+
+export const Route = createFileRoute("/$")({
+  loader: async ({ location }) => {
+    const data = await getPageData({ pathname: location.pathname });
+    if (!data) throw notFound();
+    return data;
+  },
+  head: ({ match }) => getHead({ pathname: match.pathname }),
+  component: () => <PageRenderer {...Route.useLoaderData()} />,
+  pendingComponent: StartLoading,
+  errorComponent: StartErrorBoundary,
+  notFoundComponent: StartNotFound,
+});
+```
+
+Wrap the root route's outlet with `<StartAppProvider spec={spec}>` so route
+fallback components can resolve the current route. Pass named `$computed`
+implementations through its `functions` prop.
+
 ### shadcn-svelte (Svelte)
 
 ```typescript
@@ -560,6 +624,24 @@ const { registry } = defineRegistry(catalog, {
 // <Renderer spec={spec} registry={registry} />
 ```
 
+### Devtools
+
+Drop-in inspector panel for any json-render app. Spec tree, state editor, action log, stream log, catalog browser, DOM picker.
+
+```tsx
+// React
+import { JsonRenderDevtools } from "@json-render/devtools-react";
+
+<JSONUIProvider registry={registry} handlers={handlers}>
+  <Renderer spec={spec} registry={registry} />
+  <JsonRenderDevtools spec={spec} catalog={catalog} messages={messages} />
+</JSONUIProvider>;
+```
+
+Floating toggle appears bottom-right. Hotkey: `Ctrl`/`Cmd` + `Shift` + `J`. Tree-shakes to `null` in production.
+
+Available for React, Vue, Svelte, and Solid — swap `@json-render/devtools-react` for the adapter that matches your renderer.
+
 ### Ink (Terminal)
 
 ```tsx
@@ -726,10 +808,13 @@ pnpm dev
 - http://react-email-demo.json-render.localhost:1355 - React Email Example
 - http://remotion-demo.json-render.localhost:1355 - Remotion Video Example
 - Chat Example: run `pnpm dev` in `examples/chat`
+- [Experimental Jev composition](https://json-render.dev/docs/jev): use `experimental_composeSpec` and `experimental_createEvaluator` from core with your own catalog, or select **Jev (Experimental)** in `/playground`. Unreleased; source-build instructions are in the guide.
 - Svelte Example: run `pnpm dev` in `examples/svelte` or `examples/svelte-chat`
 - Vue Example: run `pnpm dev` in `examples/vue`
 - Vite Renderers (React + Vue + Svelte + Solid): run `pnpm dev` in `examples/vite-renderers`
 - React Native example: run `npx expo start` in `examples/react-native`
+- Gaussian Splatting (R3F): run `pnpm dev` in `examples/react-three-fiber-gsplat`
+- Gaussian Splatting (experimental standalone gsplat.js demo): run `pnpm dev` in `examples/gsplat`
 
 ## How It Works
 

apps/web/.env.example

@@ -3,6 +3,10 @@
 # For local development, get your key from https://vercel.com/ai-gateway
 AI_GATEWAY_API_KEY=
 
+# Dedicated AI Gateway key for the experimental Jev playground option
+# Required locally and on Vercel; no fallback to AI_GATEWAY_API_KEY
+JEV_AI_GATEWAY_API_KEY=
+
 # AI Model Configuration
 # Override the default model used for UI generation
 # Default: anthropic/claude-haiku-4.5

apps/web/.gitignore

@@ -11,6 +11,7 @@
 
 # next.js
 /.next/
+/.source/
 /out/
 
 # production

apps/web/README.md

@@ -16,6 +16,10 @@ bun dev
 
 Open [http://json-render.localhost:1355](http://json-render.localhost:1355) with your browser to see the result.
 
+## Jev composition experiment
+
+The **default / jev** toggle in `/playground` includes an experimental Jev option; hover or focus its info icon segment for details. It is a reference consumer of core's reusable `experimental_composeSpec` and `experimental_createEvaluator` APIs. It lets Jev compose and edit UI trees from the playground's component catalog and allowed action bindings through Vercel AI Gateway. Set `JEV_AI_GATEWAY_API_KEY` on the server for Jev; the default model uses `AI_GATEWAY_API_KEY`. Follow-ups use the selected version as `initialSpec` and can add, replace, remove, or move elements; earlier versions remain unchanged. It uses the same prompt input, version history, spec/stream inspectors, and functional preview as the default model. The shared `/api/generate` endpoint streams spec patches and decision metadata. See [setup, architecture, and limits](lib/jev/README.md).
+
 You can start editing the page by modifying `app/page.tsx`. The page auto-updates as you edit the file.
 
 This project uses [`next/font`](https://nextjs.org/docs/app/building-your-application/optimizing/fonts) to automatically optimize and load Inter, a custom Google Font.

apps/web/app/(main)/docs/layout.tsx

@@ -1,35 +0,0 @@
-import { DocsMobileNav } from "@/components/docs-mobile-nav";
-import { DocsSidebar } from "@/components/docs-sidebar";
-import { CopyPageButton } from "@/components/copy-page-button";
-import { TableOfContents } from "@/components/table-of-contents";
-
-export default function DocsLayout({
-  children,
-}: {
-  children: React.ReactNode;
-}) {
-  return (
-    <>
-      <DocsMobileNav />
-      <div className="max-w-7xl mx-auto px-6 py-8 lg:py-12 flex gap-12">
-        {/* Sidebar */}
-        <aside className="w-48 shrink-0 hidden lg:block sticky top-28 h-[calc(100vh-7rem)] overflow-y-auto">
-          <DocsSidebar />
-        </aside>
-
-        {/* Content */}
-        <div className="flex-1 min-w-0 max-w-2xl pb-20">
-          <div className="flex justify-end mb-4">
-            <CopyPageButton />
-          </div>
-          <article>{children}</article>
-        </div>
-
-        {/* On this page */}
-        <aside className="w-44 shrink-0 hidden xl:block sticky top-28 h-[calc(100vh-7rem)] overflow-y-auto">
-          <TableOfContents />
-        </aside>
-      </div>
-    </>
-  );
-}

apps/web/app/(main)/examples/layout.tsx

@@ -0,0 +1,8 @@
+import type { ReactNode } from "react";
+import { pageMetadata } from "@/lib/page-metadata";
+
+export const metadata = pageMetadata("examples");
+
+export default function ExamplesLayout({ children }: { children: ReactNode }) {
+  return children;
+}

apps/web/app/(main)/layout.tsx

@@ -1,14 +1,7 @@
-import { Header } from "@/components/header";
-
 export default function MainLayout({
   children,
 }: {
   children: React.ReactNode;
 }) {
-  return (
-    <div className="min-h-screen flex flex-col">
-      <Header />
-      <main className="flex-1">{children}</main>
-    </div>
-  );
+  return <main className="min-h-[calc(100dvh-4rem)]">{children}</main>;
 }

apps/web/app/[lang]/docs/[[...slug]]/page.tsx

@@ -0,0 +1,43 @@
+import { MobileDocsBar } from "@vercel/geistdocs/mobile-docs-bar";
+import { createDocsPage } from "@vercel/geistdocs/pages/docs";
+import { notFound } from "next/navigation";
+import { GenerationModesDiagram } from "@/components/generation-modes-diagram";
+import { PackageInstall } from "@/components/package-install";
+import { isSafePathSegments } from "@/lib/docs-source";
+import { config } from "@/lib/geistdocs/config";
+import { geistdocsSource } from "@/lib/geistdocs/source";
+import { pageMetadata } from "@/lib/page-metadata";
+
+type PageProps = { params: Promise<{ lang: string; slug?: string[] }> };
+
+async function validate(params: PageProps["params"]) {
+  const resolved = await params;
+  if (resolved.lang !== "en" || !isSafePathSegments(resolved.slug ?? []))
+    notFound();
+  try {
+    if (!geistdocsSource.source.getPage(resolved.slug, resolved.lang))
+      notFound();
+  } catch (error) {
+    if (error instanceof URIError) notFound();
+    throw error;
+  }
+  return resolved;
+}
+
+const docsPage = createDocsPage({
+  config,
+  source: geistdocsSource,
+  mdx: { GenerationModesDiagram, PackageInstall },
+  renderTop: ({ data }) => <MobileDocsBar toc={data.toc} />,
+});
+
+export default async function Page({ params }: PageProps) {
+  return <docsPage.Page params={Promise.resolve(await validate(params))} />;
+}
+
+export async function generateMetadata({ params }: PageProps) {
+  const { slug = [] } = await validate(params);
+  return pageMetadata(["docs", ...slug].join("/"));
+}
+
+export const generateStaticParams = docsPage.generateStaticParams;

apps/web/app/[lang]/docs/layout.tsx

@@ -0,0 +1,25 @@
+import type { ReactNode } from "react";
+import { notFound } from "next/navigation";
+import { GeistdocsDocsLayout } from "@vercel/geistdocs/layout";
+import { config } from "@/lib/geistdocs/config";
+import { geistdocsSource } from "@/lib/geistdocs/source";
+
+export default async function DocsLayout({
+  children,
+  params,
+}: {
+  children: ReactNode;
+  params: Promise<{ lang: string }>;
+}) {
+  const { lang } = await params;
+  if (lang !== "en") notFound();
+  return (
+    <GeistdocsDocsLayout
+      config={config}
+      tree={geistdocsSource.source.getPageTree(lang)}
+      containerProps={{ className: "mx-auto max-w-[1448px]" }}
+    >
+      {children}
+    </GeistdocsDocsLayout>
+  );
+}

apps/web/app/api/docs-chat/route.ts

@@ -1,11 +1,8 @@
-import { readFile } from "fs/promises";
-import { join } from "path";
 import { convertToModelMessages, stepCountIs, streamText } from "ai";
 import type { ModelMessage, UIMessage } from "ai";
 import { createBashTool } from "bash-tool";
 import { headers } from "next/headers";
-import { allDocsPages } from "@/lib/docs-navigation";
-import { mdxToCleanMarkdown } from "@/lib/mdx-to-markdown";
+import { loadAllDocsSources } from "@/lib/docs-source";
 import { minuteRateLimit, dailyRateLimit } from "@/lib/rate-limit";
 
 export const maxDuration = 60;
@@ -16,8 +13,10 @@ const SYSTEM_PROMPT = `You are a helpful documentation assistant for json-render
 
 GitHub repository: https://github.com/vercel-labs/json-render
 Documentation: https://json-render.dev/docs
-npm packages: @json-render/core, @json-render/react, @json-render/next, @json-render/ink, @json-render/vue, @json-render/svelte, @json-render/solid, @json-render/shadcn, @json-render/shadcn-svelte, @json-render/react-three-fiber, @json-render/react-native, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/codegen, @json-render/mcp, @json-render/redux, @json-render/zustand, @json-render/jotai, @json-render/xstate, @json-render/yaml
-Skills: json-render ships AI agent skills that teach coding agents how to use each package. Install with "npx skills add vercel-labs/json-render --skill <name>". Available skills: core, react, next, ink, react-pdf, react-email, react-native, shadcn, shadcn-svelte, react-three-fiber, image, remotion, vue, svelte, solid, codegen, mcp, redux, zustand, jotai, xstate, yaml. See /docs/skills for details.
+npm packages: @json-render/core, @json-render/react, @json-render/next, @json-render/tanstack-start, @json-render/ink, @json-render/vue, @json-render/svelte, @json-render/solid, @json-render/shadcn, @json-render/shadcn-svelte, @json-render/react-three-fiber, @json-render/react-native, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/directives, @json-render/codegen, @json-render/devtools, @json-render/devtools-react, @json-render/devtools-vue, @json-render/devtools-svelte, @json-render/devtools-solid, @json-render/mcp, @json-render/redux, @json-render/zustand, @json-render/jotai, @json-render/xstate, @json-render/yaml
+Skills: json-render ships AI agent skills that teach coding agents how to use each package. Install with "npx skills add vercel-labs/json-render --skill <name>". Available skills: core, react, next, tanstack-start, ink, react-pdf, react-email, react-native, shadcn, shadcn-svelte, react-three-fiber, image, remotion, vue, svelte, solid, directives, codegen, devtools, devtools-react, devtools-vue, devtools-svelte, devtools-solid, mcp, redux, zustand, jotai, xstate, yaml. See /docs/skills for details.
+
+Experimental Jev composition: core exports experimental_composeSpec and experimental_createEvaluator for app-owned catalogs/candidates through Vercel AI Gateway. See /docs/jev for availability, source-build setup, and limits; do not assume the currently published npm version includes it.
 
 You have access to the full json-render documentation via the bash and readFile tools. The docs are available as markdown files in the /workspace/docs/ directory.
 
@@ -32,37 +31,13 @@ When answering questions:
 - Do NOT use emojis in your responses`;
 
 async function loadDocsFiles(): Promise<Record<string, string>> {
-  const files: Record<string, string> = {};
-
-  const results = await Promise.allSettled(
-    allDocsPages.map(async (page) => {
-      const slug =
-        page.href === "/docs" ? "" : page.href.replace(/^\/docs\/?/, "");
-      const filePath = slug
-        ? join(
-            process.cwd(),
-            "app",
-            "(main)",
-            "docs",
-            ...slug.split("/"),
-            "page.mdx",
-          )
-        : join(process.cwd(), "app", "(main)", "docs", "page.mdx");
-
-      const raw = await readFile(filePath, "utf-8");
-      const md = mdxToCleanMarkdown(raw);
-      const fileName = slug ? `/docs/${slug}.md` : "/docs/index.md";
-      return { fileName, md };
-    }),
+  const pages = await loadAllDocsSources();
+  return Object.fromEntries(
+    pages.map((page) => [
+      page.href === "/docs" ? "/docs/index.md" : `${page.href}.md`,
+      page.markdown,
+    ]),
   );
-
-  for (const result of results) {
-    if (result.status === "fulfilled") {
-      files[result.value.fileName] = result.value.md;
-    }
-  }
-
-  return files;
 }
 
 function addCacheControl(messages: ModelMessage[]): ModelMessage[] {

apps/web/app/api/docs-markdown/route.ts

@@ -1,55 +1,25 @@
-import { readFile } from "fs/promises";
-import { join } from "path";
 import { NextRequest, NextResponse } from "next/server";
-import { mdxToCleanMarkdown } from "@/lib/mdx-to-markdown";
+import { loadDocsSource } from "@/lib/docs-source";
 
 export async function GET(req: NextRequest) {
-  const { searchParams } = new URL(req.url);
-  const docPath = searchParams.get("path");
-
-  if (!docPath) {
+  const docPath = req.nextUrl.searchParams.get("path");
+  if (!docPath)
     return NextResponse.json(
       { error: "Missing ?path= parameter" },
       { status: 400 },
     );
-  }
-
-  // Sanitize path: only allow docs paths, no traversal
-  const normalized = docPath
-    .replace(/^\//, "")
-    .replace(/\.\./g, "")
-    .replace(/[^a-zA-Z0-9/-]/g, "");
-
-  if (!normalized.startsWith("docs")) {
+  const path = docPath.startsWith("/") ? docPath : `/${docPath}`;
+  if (!/^\/docs(?:\/[a-zA-Z0-9_-]+)*\/?$/.test(path)) {
     return NextResponse.json({ error: "Invalid path" }, { status: 400 });
   }
-
-  // Map URL path to file path
-  // /docs -> /app/(main)/docs/page.mdx
-  // /docs/installation -> /app/(main)/docs/installation/page.mdx
-  const slug = normalized === "docs" ? "" : normalized.replace(/^docs\/?/, "");
-  const filePath = slug
-    ? join(
-        process.cwd(),
-        "app",
-        "(main)",
-        "docs",
-        ...slug.split("/"),
-        "page.mdx",
-      )
-    : join(process.cwd(), "app", "(main)", "docs", "page.mdx");
-
-  try {
-    const raw = await readFile(filePath, "utf-8");
-    const markdown = mdxToCleanMarkdown(raw);
-
-    return new NextResponse(markdown, {
-      headers: {
-        "Content-Type": "text/markdown; charset=utf-8",
-        "Cache-Control": "public, max-age=3600",
-      },
-    });
-  } catch {
+  const page = await loadDocsSource(path);
+  if (!page)
     return NextResponse.json({ error: "Page not found" }, { status: 404 });
-  }
+  return new NextResponse(page.markdown, {
+    headers: {
+      "Content-Type": "text/markdown; charset=utf-8",
+      "Cache-Control": "public, max-age=3600",
+      Link: `<${page.canonicalUrl}>; rel="canonical"`,
+    },
+  });
 }

apps/web/app/api/docs-md/[[...slug]]/route.ts

@@ -0,0 +1,21 @@
+import { loadDocsSource, isSafePathSegments } from "@/lib/docs-source";
+import { applyDocsResponseHeaders } from "@/lib/docs-response-headers";
+
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ slug?: string[] }> },
+) {
+  const { slug = [] } = await params;
+  const path = `/docs${slug.length ? `/${slug.join("/")}` : ""}`;
+  const page = isSafePathSegments(slug) ? await loadDocsSource(path) : null;
+  const headers = new Headers({
+    "Content-Type": "text/markdown; charset=utf-8",
+  });
+  applyDocsResponseHeaders(headers);
+  if (page) headers.set("Link", `<${page.canonicalUrl}>; rel="canonical"`);
+  return new Response(
+    page?.markdown ??
+      "# Page Not Found\n\nSee [the documentation index](/llms.txt).\n",
+    { status: page ? 200 : 404, headers },
+  );
+}

apps/web/app/api/generate/route.ts

@@ -10,17 +10,21 @@ import { yamlPrompt } from "@json-render/yaml";
 import { stringify as yamlStringify } from "yaml";
 import { minuteRateLimit, dailyRateLimit } from "@/lib/rate-limit";
 import { playgroundCatalog } from "@/lib/render/catalog";
+import { createCompositionResponse } from "@/lib/jev/response";
 
-export const maxDuration = 30;
+export const maxDuration = 60;
 
 const PLAYGROUND_RULES = [
   "NEVER use viewport height classes (min-h-screen, h-screen) - the UI renders inside a fixed-size container.",
   "NEVER use page background colors (bg-gray-50) - the container has its own background.",
   "For forms or small UIs: use Card as root with maxWidth:'sm' or 'md' and centered:true.",
-  "For content-heavy UIs (blogs, dashboards, product listings): use Stack or Grid as root. Use Grid with 2-3 columns for card layouts.",
+  "For content-heavy UIs (blogs, dashboards, product listings): use Stack or Grid as root. Use Grid with 2-3 columns for card layouts. Keep the total UI compact — avoid sprawling multi-section pages. Prefer a single focused Card over a full page layout.",
   "Wrap each repeated item in a Card for visual separation and structure.",
   "Use realistic, professional sample data. Include 3-5 items with varied content. Never leave state arrays empty.",
   'For form inputs (Input, Textarea, Select), always include checks for validation (e.g. required, email, minLength). Always pair checks with a $bindState expression on the value prop (e.g. { "$bindState": "/path" }).',
+  "NEVER use emoji characters. Use the Icon component with Lucide icon names instead. For example, use Icon with name:'MapPin' instead of a pin emoji, Icon with name:'Mail' instead of an envelope emoji, etc.",
+  "For icon+label patterns, use a horizontal Stack with gap:'sm' and align:'center' containing an Icon and a Text.",
+  "For any tabular or list data with consistent columns (items, orders, stats), ALWAYS use the Table component. Never simulate tables with Stacks — the columns won't align.",
 ];
 
 const MAX_PROMPT_LENGTH = 500;
@@ -89,7 +93,9 @@ export async function POST(req: Request) {
     );
   }
 
-  const { prompt, context, format, editModes } = await req.json();
+  const { prompt, context, format, editModes, model } = await req.json();
+  if (model === "typesafe-ai/jev")
+    return createCompositionResponse(req, prompt, context?.previousSpec);
   const isYaml = format === "yaml";
 
   const systemPrompt = getSystemPrompt(isYaml, editModes);
@@ -104,6 +110,7 @@ export async function POST(req: Request) {
 
   const result = streamText({
     model: process.env.AI_GATEWAY_MODEL || DEFAULT_MODEL,
+    abortSignal: req.signal,
     system: [
       {
         role: "system",

apps/web/app/api/search/route.ts

@@ -1,7 +1,13 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getSearchIndex } from "@/lib/search-index";
+import { createSearchRoute } from "@vercel/geistdocs/routes/search";
+import { geistdocsSource } from "@/lib/geistdocs/source";
+import { config } from "@/lib/geistdocs/config";
+
+const docsSearch = createSearchRoute({ config, source: geistdocsSource });
 
 export async function GET(req: NextRequest) {
+  if (req.nextUrl.searchParams.has("query")) return docsSearch(req);
   const q = req.nextUrl.searchParams.get("q")?.trim().toLowerCase();
 
   if (!q) {

apps/web/app/globals.css

@@ -1,9 +1,16 @@
-@import "tailwindcss";
-@import "tw-animate-css";
+@import "@vercel/geistdocs/styles.css";
+
+@theme {
+  --breakpoint-sm: 40rem;
+  --breakpoint-md: 48rem;
+  --breakpoint-lg: 64rem;
+  --breakpoint-xl: 80rem;
+  --breakpoint-2xl: 96rem;
+}
 
 @source "../node_modules/streamdown/dist/index.js";
 
-@custom-variant dark (&:is(.dark *));
+@custom-variant dark (&:is(.dark-theme *));
 
 :root {
   --radius: 0.5rem;
@@ -31,7 +38,7 @@
   --chat-bg: oklch(0.95 0 0);
 }
 
-.dark {
+.dark-theme {
   --ds-gray-500: oklch(0.39 0 0);
   /* Monochrome dark theme */
   --background: oklch(0.0 0 0);
@@ -189,9 +196,31 @@ article table {
   background-color: var(--shiki-light-bg) !important;
 }
 
-.dark .shiki,
-.dark .shiki span {
+.dark-theme .shiki,
+.dark-theme .shiki span {
   color: var(--shiki-dark) !important;
   background-color: var(--shiki-dark-bg) !important;
 }
 
+@container (width < 1200px) {
+  #nd-page { @apply px-6 pt-6; }
+  #nd-page > [data-mobile-docs-bar],
+  #nd-page > div:has([data-mobile-toc-trigger]) { display: flex; }
+  #nd-page [data-mobile-toc-trigger] { width: 44px; height: 44px; }
+  #nd-page > div:has(> h1) { padding-inline-end: 3.5rem; }
+  #nd-page > div:has(> h1) + div,
+  #nd-page > div:has(> h1) + p + div { margin-top: 0; }
+}
+
+@container (961px <= width < 1200px) {
+  #nd-page > [data-mobile-docs-bar] { display: none; }
+}
+
+header .pointer-events-none.opacity-0 {
+  visibility: hidden;
+}
+
+#nd-page div:has(> [aria-live="polite"]) > div > .max-sm\:hidden {
+  display: flex;
+}
+

apps/web/app/layout.tsx

@@ -3,11 +3,16 @@ import localFont from "next/font/local";
 import { GeistPixelSquare } from "geist/font/pixel";
 import "./globals.css";
 import { ThemeProvider } from "@/components/theme-provider";
+import { DocsProvider } from "@/components/geistdocs-provider";
+import { Navbar } from "@vercel/geistdocs/navbar";
+import { Footer } from "@vercel/geistdocs/footer";
+import { config } from "@/lib/geistdocs/config";
 import { DocsChat } from "@/components/docs-chat";
 import { Analytics } from "@vercel/analytics/next";
 import { SpeedInsights } from "@vercel/speed-insights/next";
 import { PAGE_TITLES } from "@/lib/page-titles";
 import { cookies } from "next/headers";
+import { isPreview, siteUrl, siteDescription } from "@/lib/site";
 
 const geistSans = localFont({
   src: "./fonts/GeistVF.woff",
@@ -19,7 +24,8 @@ const geistMono = localFont({
 });
 
 export const metadata: Metadata = {
-  metadataBase: new URL("https://json-render.dev"),
+  metadataBase: new URL(siteUrl),
+  alternates: { canonical: "/" },
   title: {
     default: `json-render | ${PAGE_TITLES[""]}`,
     template: "%s | json-render",
@@ -64,8 +70,8 @@ export const metadata: Metadata = {
     images: ["/og"],
   },
   robots: {
-    index: true,
-    follow: true,
+    index: !isPreview,
+    follow: !isPreview,
   },
   icons: {
     icon: "/favicon.ico",
@@ -79,15 +85,30 @@ export default async function RootLayout({
 }>) {
   const cookieStore = await cookies();
   const chatOpen = cookieStore.get("docs-chat-open")?.value === "true";
-  const chatWidth = Number(cookieStore.get("docs-chat-width")?.value) || 400;
+  const chatWidth = Math.min(
+    700,
+    Math.max(300, Number(cookieStore.get("docs-chat-width")?.value) || 400),
+  );
 
   return (
     <html lang="en" suppressHydrationWarning>
       <head>
+        <script
+          type="application/ld+json"
+          dangerouslySetInnerHTML={{
+            __html: JSON.stringify({
+              "@context": "https://schema.org",
+              "@type": "WebSite",
+              name: "json-render",
+              url: siteUrl,
+              description: siteDescription,
+            }),
+          }}
+        />
         {chatOpen && (
           <style
             dangerouslySetInnerHTML={{
-              __html: `@media(min-width:640px){body{padding-right:${chatWidth}px}}`,
+              __html: `@media(min-width:640px){body{padding-right:min(${chatWidth}px, calc(100vw - 320px))}}`,
             }}
           />
         )}
@@ -96,7 +117,11 @@ export default async function RootLayout({
         className={`${geistSans.variable} ${geistMono.variable} ${GeistPixelSquare.variable}`}
       >
         <ThemeProvider>
-          {children}
+          <DocsProvider>
+            <Navbar config={config} />
+            {children}
+            <Footer />
+          </DocsProvider>
           <DocsChat defaultOpen={chatOpen} defaultWidth={chatWidth} />
         </ThemeProvider>
         <Analytics />

apps/web/app/llms.txt/route.ts

@@ -0,0 +1,10 @@
+import { loadAllDocsSources } from "@/lib/docs-source";
+import { siteDescription, siteUrl } from "@/lib/site";
+
+export async function GET() {
+  const pages = await loadAllDocsSources();
+  const body = `# json-render\n\n${siteDescription}\n\n## Documentation\n\n${pages.map((page) => `- [${page.title}](${siteUrl}${page.markdownUrl})`).join("\n")}\n`;
+  return new Response(body, {
+    headers: { "Content-Type": "text/plain; charset=utf-8" },
+  });
+}

apps/web/app/playground/layout.tsx

@@ -3,5 +3,9 @@ export default function PlaygroundLayout({
 }: {
   children: React.ReactNode;
 }) {
-  return <div className="h-dvh flex flex-col overflow-hidden">{children}</div>;
+  return (
+    <main className="h-[calc(100dvh-4rem)] flex flex-col overflow-hidden">
+      {children}
+    </main>
+  );
 }

apps/web/app/robots.ts

@@ -0,0 +1,11 @@
+import type { MetadataRoute } from "next";
+import { isPreview, siteUrl } from "@/lib/site";
+
+export default function robots(): MetadataRoute.Robots {
+  return {
+    rules: isPreview
+      ? { userAgent: "*", disallow: "/" }
+      : { userAgent: "*", allow: "/" },
+    sitemap: `${siteUrl}/sitemap.xml`,
+  };
+}

apps/web/app/sitemap.md/route.ts

@@ -0,0 +1,10 @@
+import { docsPages } from "@/lib/docs-source";
+
+export function GET() {
+  return new Response(
+    `# json-render documentation\n\n${docsPages.map((page) => `- [${page.title}](${page.href})`).join("\n")}\n`,
+    {
+      headers: { "Content-Type": "text/markdown; charset=utf-8" },
+    },
+  );
+}

apps/web/app/sitemap.ts

@@ -0,0 +1,9 @@
+import type { MetadataRoute } from "next";
+import { PAGE_TITLES } from "@/lib/page-titles";
+import { siteUrl } from "@/lib/site";
+
+export default function sitemap(): MetadataRoute.Sitemap {
+  return Object.keys(PAGE_TITLES).map((slug) => ({
+    url: `${siteUrl}/${slug}`,
+  }));
+}

apps/web/components/demo.tsx

@@ -18,65 +18,62 @@ import { PlaygroundRenderer } from "@/lib/render/renderer";
 import { playgroundCatalog } from "@/lib/render/catalog";
 import { buildCatalogDisplayData } from "@/lib/render/catalog-display";
 
-const SIMULATION_PROMPT = "Create a contact form with name, email, and message";
+const SIMULATION_PROMPT = "Show a team performance dashboard";
 
 interface SimulationStage {
   tree: Spec;
   stream: string;
 }
 
-// Shared state & element definitions for the progressive simulation stages.
-const FORM_STATE = { form: { name: "", email: "", message: "" } };
+const DASH_STATE = {
+  chartData: [
+    { label: "Mon", value: 12 },
+    { label: "Tue", value: 28 },
+    { label: "Wed", value: 19 },
+    { label: "Thu", value: 34 },
+    { label: "Fri", value: 45 },
+    { label: "Sat", value: 38 },
+    { label: "Sun", value: 52 },
+  ],
+};
 
-const NAME_INPUT = {
-  type: "Input",
+const METRIC_REVENUE = {
+  type: "Metric",
   props: {
-    label: "Name",
-    name: "name",
-    statePath: "/form/name",
-    checks: [{ type: "required", message: "Name is required" }],
+    label: "Weekly Revenue",
+    value: "12,400",
+    prefix: "$",
+    change: "+18%",
+    changeType: "positive",
   },
 } as const;
 
-const EMAIL_INPUT = {
-  type: "Input",
-  props: {
-    label: "Email",
-    name: "email",
-    type: "email",
-    statePath: "/form/email",
-    checks: [
-      { type: "required", message: "Email is required" },
-      { type: "email", message: "Please enter a valid email" },
-    ],
-  },
+const CHART = {
+  type: "LineGraph",
+  props: { data: { $state: "/chartData" } },
 } as const;
 
-const MESSAGE_INPUT = {
-  type: "Textarea",
-  props: {
-    label: "Message",
-    name: "message",
-    statePath: "/form/message",
-    checks: [{ type: "required", message: "Message is required" }],
-  },
+const SEP = { type: "Separator", props: {} } as const;
+
+const PROGRESS_DEALS = {
+  type: "Progress",
+  props: { value: 72, label: "Deals Closed -- 72%" },
 } as const;
 
-const SUBMIT_BUTTON = {
-  type: "Button",
-  props: { label: "Send Message", variant: "primary" },
-  on: { press: { action: "formSubmit" } },
+const PROGRESS_RETENTION = {
+  type: "Progress",
+  props: { value: 91, label: "Retention -- 91%" },
 } as const;
 
 const SIMULATION_STAGES: SimulationStage[] = [
   {
     tree: {
       root: "card",
-      state: FORM_STATE,
+      state: DASH_STATE,
       elements: {
         card: {
           type: "Card",
-          props: { title: "Contact Us", maxWidth: "md" },
+          props: { title: "Team Performance", maxWidth: "sm", centered: true },
           children: [],
         },
       },
@@ -86,72 +83,74 @@ const SIMULATION_STAGES: SimulationStage[] = [
   {
     tree: {
       root: "card",
-      state: FORM_STATE,
+      state: DASH_STATE,
       elements: {
         card: {
           type: "Card",
-          props: { title: "Contact Us", maxWidth: "md" },
-          children: ["name"],
+          props: { title: "Team Performance", maxWidth: "sm", centered: true },
+          children: ["m1"],
         },
-        name: NAME_INPUT,
+        m1: METRIC_REVENUE,
       },
     },
     stream:
-      '{"op":"add","path":"/elements/name","value":{"type":"Input","props":{"label":"Name","name":"name","statePath":"/form/name","checks":[{"type":"required","message":"Name is required"}]}}}',
+      '{"op":"add","path":"/elements/m1","value":{"type":"Metric","props":{"label":"Weekly Revenue","value":"12,400","prefix":"$","change":"+18%","changeType":"positive"}}}',
   },
   {
     tree: {
       root: "card",
-      state: FORM_STATE,
+      state: DASH_STATE,
       elements: {
         card: {
           type: "Card",
-          props: { title: "Contact Us", maxWidth: "md" },
-          children: ["name", "email"],
+          props: { title: "Team Performance", maxWidth: "sm", centered: true },
+          children: ["m1", "chart"],
         },
-        name: NAME_INPUT,
-        email: EMAIL_INPUT,
+        m1: METRIC_REVENUE,
+        chart: CHART,
       },
     },
     stream:
-      '{"op":"add","path":"/elements/email","value":{"type":"Input","props":{"label":"Email","name":"email","type":"email","statePath":"/form/email","checks":[{"type":"required","message":"Email is required"},{"type":"email","message":"Please enter a valid email"}]}}}',
+      '{"op":"add","path":"/elements/chart","value":{"type":"LineGraph","props":{"data":{"$state":"/chartData"}}}}',
   },
   {
     tree: {
       root: "card",
-      state: FORM_STATE,
+      state: DASH_STATE,
       elements: {
         card: {
           type: "Card",
-          props: { title: "Contact Us", maxWidth: "md" },
-          children: ["name", "email", "message"],
+          props: { title: "Team Performance", maxWidth: "sm", centered: true },
+          children: ["m1", "chart", "sep", "p1"],
         },
-        name: NAME_INPUT,
-        email: EMAIL_INPUT,
-        message: MESSAGE_INPUT,
+        m1: METRIC_REVENUE,
+        chart: CHART,
+        sep: SEP,
+        p1: PROGRESS_DEALS,
       },
     },
     stream:
-      '{"op":"add","path":"/elements/message","value":{"type":"Textarea","props":{"label":"Message","name":"message","statePath":"/form/message","checks":[{"type":"required","message":"Message is required"}]}}}',
+      '{"op":"add","path":"/elements/p1","value":{"type":"Progress","props":{"value":72,"label":"Deals Closed -- 72%"}}}',
   },
   {
     tree: {
       root: "card",
-      state: FORM_STATE,
+      state: DASH_STATE,
       elements: {
         card: {
           type: "Card",
-          props: { title: "Contact Us", maxWidth: "md" },
-          children: ["name", "email", "message", "submit"],
+          props: { title: "Team Performance", maxWidth: "sm", centered: true },
+          children: ["m1", "chart", "sep", "p1", "p2"],
         },
-        name: NAME_INPUT,
-        email: EMAIL_INPUT,
-        message: MESSAGE_INPUT,
-        submit: SUBMIT_BUTTON,
+        m1: METRIC_REVENUE,
+        chart: CHART,
+        sep: SEP,
+        p1: PROGRESS_DEALS,
+        p2: PROGRESS_RETENTION,
       },
     },
     stream:
-      '{"op":"add","path":"/elements/submit","value":{"type":"Button","props":{"label":"Send Message","variant":"primary"},"on":{"press":{"action":"formSubmit"}}}}',
+      '{"op":"add","path":"/elements/p2","value":{"type":"Progress","props":{"value":91,"label":"Retention -- 91%"}}}',
   },
 ];
 
@@ -196,6 +195,15 @@ function specToNested(spec: Spec): Record<string, unknown> {
       node.children = el.children.map(resolve);
     }
 
+    if (el.slots && Object.keys(el.slots).length > 0) {
+      node.slots = Object.fromEntries(
+        Object.entries(el.slots).map(([slotName, childKeys]) => [
+          slotName,
+          childKeys.map(resolve),
+        ]),
+      );
+    }
+
     return node;
   }
 
@@ -211,10 +219,10 @@ function specToNested(spec: Spec): Record<string, unknown> {
 }
 
 const EXAMPLE_PROMPTS = [
-  "Create a login form with email and password",
-  "Build a feedback form with rating stars",
-  "Design a contact card with avatar",
-  "Make a settings panel with toggles",
+  "Recipe card with rating and ingredients",
+  "Order receipt with item list and total",
+  "Team member profile card",
+  "Notification inbox with alerts",
 ];
 
 export function Demo({
@@ -394,21 +402,45 @@ export function Demo({
 
       const propsStr = serializeProps(propsObj);
       const hasChildren = element.children && element.children.length > 0;
+      const hasSlots = element.slots && Object.keys(element.slots).length > 0;
 
-      if (!hasChildren) {
+      if (!hasChildren && !hasSlots) {
         return propsStr
           ? `${spaces}<${componentName} ${propsStr} />`
           : `${spaces}<${componentName} />`;
       }
 
       const lines: string[] = [];
-      lines.push(
-        propsStr
-          ? `${spaces}<${componentName} ${propsStr}>`
-          : `${spaces}<${componentName}>`,
-      );
+      if (hasSlots) {
+        lines.push(`${spaces}<${componentName}`);
+        if (propsStr) {
+          lines.push(`${spaces}  ${propsStr}`);
+        }
+        for (const [slotName, childKeys] of Object.entries(element.slots!)) {
+          const slotChildren = childKeys
+            .map((childKey) => generateJSX(childKey, indent + 2))
+            .filter(Boolean);
+          if (slotChildren.length === 0) continue;
+          lines.push(`${spaces}  ${slotName}={`);
+          if (slotChildren.length > 1) {
+            lines.push(`${spaces}    <>`);
+          }
+          lines.push(...slotChildren);
+          if (slotChildren.length > 1) {
+            lines.push(`${spaces}    </>`);
+          }
+          lines.push(`${spaces}  }`);
+        }
+        lines.push(`${spaces}>`);
+      } else {
+        lines.push(
+          propsStr
+            ? `${spaces}<${componentName} ${propsStr}>`
+            : `${spaces}<${componentName}>`,
+        );
+      }
 
-      for (const childKey of element.children!) {
+      for (const childKey of element.children ?? []) {
         lines.push(generateJSX(childKey, indent + 1));
       }
 
@@ -1117,7 +1149,7 @@ Open [http://localhost:3000](http://localhost:3000) to view.
             ))}
           </div>
           <div
-            className={`border border-border rounded bg-background font-mono text-xs text-left grid relative group ${fullscreen ? "flex-1 min-h-0" : "h-[28rem]"}`}
+            className={`border border-border rounded bg-background font-mono text-xs text-left grid relative group ${fullscreen ? "flex-1 min-h-0" : "h-[36rem]"}`}
           >
             {activeTab !== "catalog" && (
               <div className="absolute top-2 right-2 z-10">
@@ -1357,7 +1389,7 @@ Open [http://localhost:3000](http://localhost:3000) to view.
             </div>
           </div>
           <div
-            className={`border border-border rounded bg-background grid relative group ${fullscreen ? "flex-1 min-h-0" : "h-[28rem]"}`}
+            className={`border border-border rounded bg-background grid relative group ${fullscreen ? "flex-1 min-h-0" : "h-[36rem]"}`}
           >
             {renderView === "static" && (
               <div className="absolute top-2 right-2 z-10">

apps/web/components/docs-chat.tsx

@@ -141,6 +141,7 @@ export function DocsChat({
   );
   const messagesScrollRef = useRef<HTMLDivElement>(null);
   const inputRef = useRef<HTMLTextAreaElement>(null);
+  const launcherRef = useRef<HTMLButtonElement>(null);
   const restoredRef = useRef(false);
   const isDraggingRef = useRef(false);
 
@@ -173,13 +174,51 @@ export function DocsChat({
     }
   }, [open, hasMounted]);
 
+  useEffect(() => {
+    const launcher = launcherRef.current;
+    if (!hasMounted || open || !launcher) return;
+    const footer = document.querySelector("footer");
+    let frame = 0;
+    const update = () => {
+      frame = 0;
+      const rect = document
+        .querySelector("footer fieldset")
+        ?.getBoundingClientRect();
+      const overlap =
+        rect && rect.width > 0 && rect.bottom > 0
+          ? Math.max(0, innerHeight - rect.top)
+          : 0;
+      launcher.style.setProperty("--chat-launcher-bottom", `${24 + overlap}px`);
+    };
+    const schedule = () => {
+      if (!frame) frame = requestAnimationFrame(update);
+    };
+    const resize = new ResizeObserver(schedule);
+    resize.observe(document.body);
+    const mutation = new MutationObserver(schedule);
+    if (footer) {
+      resize.observe(footer);
+      mutation.observe(footer, { childList: true, subtree: true });
+    }
+    window.addEventListener("scroll", schedule, { passive: true });
+    window.addEventListener("resize", schedule);
+    update();
+    return () => {
+      cancelAnimationFrame(frame);
+      resize.disconnect();
+      mutation.disconnect();
+      window.removeEventListener("scroll", schedule);
+      window.removeEventListener("resize", schedule);
+    };
+  }, [hasMounted, open]);
+
   // Push page content on desktop when pane is open.
   // Use padding on body so the page scrollbar stays at the viewport edge (behind the sidebar)
   // instead of appearing right next to the sidebar's scrollbar.
   useEffect(() => {
     const body = document.body;
     if (isDesktop && open) {
-      body.style.paddingRight = `${desktopWidth}px`;
+      body.style.paddingRight = `min(${desktopWidth}px, calc(100vw - 320px))`;
       if (!isDraggingRef.current) {
         body.style.transition = "padding-right 150ms ease";
       }
@@ -273,7 +312,13 @@ export function DocsChat({
           return !prev;
         });
       }
-      if (e.key === "Escape" && open && isDesktop) {
+      if (
+        e.key === "Escape" &&
+        open &&
+        (isDesktop ||
+          (e.target instanceof Element &&
+            e.target.closest("#json-render-chat-mobile")))
+      ) {
         setOpen(false);
       }
     };
@@ -459,6 +504,7 @@ export function DocsChat({
           rows={1}
           enterKeyHint="send"
           placeholder="Ask a question..."
+          aria-label="Ask a question"
           onKeyDown={(e) => {
             if (e.key === "Enter" && !e.shiftKey) {
               e.preventDefault();
@@ -496,12 +542,19 @@ export function DocsChat({
       {/* Ask AI trigger button */}
       {!open && (
         <button
+          ref={launcherRef}
+          data-docs-chat-launcher
           onClick={() => setOpen(true)}
-          className="fixed z-50 bottom-4 left-1/2 -translate-x-1/2 sm:left-auto sm:translate-x-0 sm:right-4 flex items-center gap-2 px-4 py-2 rounded-lg border border-primary bg-primary text-primary-foreground shadow-lg hover:bg-primary/90 transition-colors text-sm font-medium"
+          className="fixed z-30 bottom-[calc(1rem+env(safe-area-inset-bottom))] left-1/2 -translate-x-1/2 min-[640px]:left-auto min-[640px]:translate-x-0 min-[640px]:right-6 min-[640px]:bottom-[var(--chat-launcher-bottom,24px)] flex h-10 items-center gap-2 px-4 py-2 rounded-lg border border-primary bg-primary text-primary-foreground shadow-lg hover:bg-primary/90 transition-colors text-sm font-medium"
           aria-label="Ask AI"
+          aria-expanded={open}
+          aria-controls={
+            isDesktop ? "json-render-chat-desktop" : "json-render-chat-mobile"
+          }
+          aria-keyshortcuts="Meta+I Control+I"
         >
           Ask AI
-          <kbd className="hidden sm:inline-flex items-center gap-0.5 text-xs opacity-60 font-mono">
+          <kbd className="hidden min-[640px]:inline-flex items-center gap-0.5 text-xs opacity-60 font-mono">
             <span>&#8984;</span>I
           </kbd>
         </button>
@@ -509,9 +562,11 @@ export function DocsChat({
 
       {/* Desktop: resizable side pane — always rendered, hidden on mobile via CSS */}
       <aside
+        id="json-render-chat-desktop"
+        inert={!open || !isDesktop}
         className={`hidden sm:flex fixed top-0 right-0 bottom-0 z-40 border-l bg-background transition-transform duration-150 ease-in-out ${open ? "translate-x-0" : "translate-x-full"}`}
-        style={{ width: desktopWidth }}
-        aria-hidden={!open}
+        style={{ width: `min(${desktopWidth}px, calc(100vw - 320px))` }}
+        aria-hidden={!open || !isDesktop}
       >
         {/* Resize handle */}
         <div
@@ -525,6 +580,8 @@ export function DocsChat({
       {hasMounted && !isDesktop && (
         <Sheet open={open} onOpenChange={setOpen}>
           <SheetContent
+            id="json-render-chat-mobile"
+            aria-describedby={undefined}
             side="right"
             overlayClassName="!bg-background"
             className="!inset-0 !w-full !h-full !max-w-none p-0 flex flex-col"

apps/web/components/geistdocs-provider.tsx

@@ -0,0 +1,13 @@
+"use client";
+
+import { GeistdocsProvider } from "@vercel/geistdocs/layout";
+import type { ReactNode } from "react";
+import { config } from "@/lib/geistdocs/config";
+
+export function DocsProvider({ children }: { children: ReactNode }) {
+  return (
+    <GeistdocsProvider config={config} lang="en">
+      {children}
+    </GeistdocsProvider>
+  );
+}

apps/web/components/header.tsx

@@ -19,7 +19,13 @@ const navLinks = [
   { href: "/docs", label: "Docs" },
 ];
 
-function GitHubLink({ className }: { className?: string }) {
+function GitHubLink({
+  className,
+  stars,
+}: {
+  className?: string;
+  stars?: string;
+}) {
   return (
     <a
       href="https://github.com/vercel-labs/json-render"
@@ -38,12 +44,12 @@ function GitHubLink({ className }: { className?: string }) {
       >
         <path d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.013 8.013 0 0016 8c0-4.42-3.58-8-8-8z" />
       </svg>
-      <span>12k</span>
+      {stars && <span>{stars}</span>}
     </a>
   );
 }
 
-export function Header() {
+export function Header({ stars }: { stars?: string }) {
   const pathname = usePathname();
   const [mobileOpen, setMobileOpen] = useState(false);
 
@@ -122,14 +128,14 @@ export function Header() {
             </Link>
           ))}
           <Search />
-          <GitHubLink />
+          <GitHubLink stars={stars} />
           <ThemeToggle />
         </nav>
 
         {/* Mobile nav */}
         <div className="flex sm:hidden items-center gap-3">
           <Search />
-          <GitHubLink />
+          <GitHubLink stars={stars} />
           <Sheet open={mobileOpen} onOpenChange={setMobileOpen}>
             <SheetTrigger
               className="flex items-center justify-center"

apps/web/components/playground.tsx

@@ -11,6 +11,8 @@ import {
   usePlaygroundStream,
   type StreamFormat,
   type TokenUsage,
+  type PlaygroundModel,
+  type CompositionSummary,
 } from "@/lib/use-playground-stream";
 import {
   ResizablePanelGroup,
@@ -20,7 +22,13 @@ import {
 import { CodeBlock } from "./code-block";
 import { CopyButton } from "./copy-button";
 import { Toaster } from "./ui/sonner";
-import { Header } from "./header";
+import { InfoIcon } from "lucide-react";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "./ui/tooltip";
 import { Sheet, SheetContent, SheetTitle } from "./ui/sheet";
 import { JsonEditor } from "@visual-json/react";
 import type { JsonValue } from "@visual-json/react";
@@ -43,7 +51,10 @@ interface Version {
   id: string;
   prompt: string;
   tree: Spec | null;
-  status: "generating" | "complete" | "error";
+  status: "generating" | "complete" | "error" | "partial" | "unavailable";
+  model: PlaygroundModel;
+  composition: CompositionSummary | null;
+  message?: string;
   usage: TokenUsage | null;
   rawLines: string[];
   format: StreamFormat;
@@ -54,7 +65,97 @@ function formatTokens(n: number): string {
   return String(n);
 }
 
+function ModelToggle({
+  model,
+  onChange,
+  disabled,
+}: {
+  model: PlaygroundModel;
+  onChange: (model: PlaygroundModel) => void;
+  disabled: boolean;
+}) {
+  return (
+    <TooltipProvider delayDuration={200}>
+      <div
+        role="group"
+        aria-label="Model"
+        className="flex shrink-0 items-center rounded border border-border text-[10px] font-mono overflow-hidden"
+      >
+        <button
+          type="button"
+          aria-label="Default model"
+          aria-pressed={model === "default"}
+          disabled={disabled}
+          onClick={() => onChange("default")}
+          className={`px-1.5 py-0.5 transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-inset disabled:opacity-50 ${
+            model === "default"
+              ? "bg-muted text-foreground"
+              : "text-muted-foreground hover:text-foreground"
+          }`}
+        >
+          default
+        </button>
+        <Tooltip>
+          <TooltipTrigger asChild>
+            <button
+              type="button"
+              aria-label="Jev (experimental)"
+              aria-pressed={model === "typesafe-ai/jev"}
+              disabled={disabled}
+              onClick={() => onChange("typesafe-ai/jev")}
+              className={`flex items-center gap-1 px-1.5 py-0.5 transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-inset disabled:opacity-50 ${
+                model === "typesafe-ai/jev"
+                  ? "bg-muted text-foreground"
+                  : "text-muted-foreground hover:text-foreground"
+              }`}
+            >
+              jev
+              <InfoIcon className="size-2.5" aria-hidden="true" />
+            </button>
+          </TooltipTrigger>
+          <TooltipContent
+            side="top"
+            align="start"
+            sideOffset={6}
+            className="max-w-64 space-y-1"
+          >
+            <p className="font-medium">Experimental</p>
+            <p>
+              Jev composes and edits UI from prepared fields, data, and actions.
+              Results may be incomplete.
+            </p>
+          </TooltipContent>
+        </Tooltip>
+      </div>
+    </TooltipProvider>
+  );
+}
+
+function VersionDetails({ version }: { version: Version }) {
+  return (
+    <>
+      <div className="mt-1 ml-6 text-[10px] font-mono text-muted-foreground/60">
+        {version.model === "typesafe-ai/jev"
+          ? "Jev · Experimental"
+          : "Default model"}
+        {version.composition &&
+          ` · ${(version.composition.elapsedMs / 1000).toFixed(2)} s · ${version.composition.calls} calls`}
+        {version.status === "partial" && " · partial"}
+        {version.status === "unavailable" && " · unavailable"}
+      </div>
+      {version.message && (
+        <p className="mt-1 ml-6 text-xs text-muted-foreground">
+          {version.message}
+        </p>
+      )}
+    </>
+  );
+}
+
 function PlaygroundControls({
+  model,
+  setModel,
+  disabled,
   format,
   setFormat,
   editModes,
@@ -62,6 +163,9 @@ function PlaygroundControls({
   showClear,
   onClear,
 }: {
+  model: PlaygroundModel;
+  setModel: (model: PlaygroundModel) => void;
+  disabled: boolean;
   format: StreamFormat;
   setFormat: (f: StreamFormat) => void;
   editModes: EditMode[];
@@ -70,46 +174,53 @@ function PlaygroundControls({
   onClear: () => void;
 }) {
   return (
-    <div className="flex items-center gap-2">
-      <div className="flex items-center rounded border border-border text-[10px] font-mono overflow-hidden">
-        {(["jsonl", "yaml"] as const).map((f) => (
-          <button
-            key={f}
-            onClick={() => setFormat(f)}
-            className={`px-1.5 py-0.5 transition-colors ${
-              format === f
-                ? "bg-muted text-foreground"
-                : "text-muted-foreground hover:text-foreground"
-            }`}
-          >
-            {f}
-          </button>
-        ))}
-      </div>
-      <div className="flex items-center rounded border border-border text-[10px] font-mono overflow-hidden">
-        {(["patch", "merge", "diff"] as const).map((m) => (
-          <button
-            key={m}
-            onClick={() => {
-              setEditModes((prev) =>
-                prev.includes(m)
-                  ? prev.length > 1
-                    ? prev.filter((x) => x !== m)
-                    : prev
-                  : [...prev, m],
-              );
-            }}
-            className={`px-1.5 py-0.5 transition-colors ${
-              editModes.includes(m)
-                ? "bg-muted text-foreground"
-                : "text-muted-foreground hover:text-foreground"
-            }`}
-          >
-            {m}
-          </button>
-        ))}
-      </div>
-      {showClear && (
+    <div className="flex min-w-0 flex-wrap items-center gap-2">
+      <ModelToggle model={model} onChange={setModel} disabled={disabled} />
+      {model !== "typesafe-ai/jev" && (
+        <>
+          <div className="flex shrink-0 items-center rounded border border-border text-[10px] font-mono overflow-hidden">
+            {(["jsonl", "yaml"] as const).map((f) => (
+              <button
+                key={f}
+                disabled={disabled}
+                onClick={() => setFormat(f)}
+                className={`px-1.5 py-0.5 transition-colors ${
+                  format === f
+                    ? "bg-muted text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                }`}
+              >
+                {f}
+              </button>
+            ))}
+          </div>
+          <div className="flex shrink-0 items-center rounded border border-border text-[10px] font-mono overflow-hidden">
+            {(["patch", "merge", "diff"] as const).map((m) => (
+              <button
+                key={m}
+                disabled={disabled}
+                onClick={() => {
+                  setEditModes((prev) =>
+                    prev.includes(m)
+                      ? prev.length > 1
+                        ? prev.filter((x) => x !== m)
+                        : prev
+                      : [...prev, m],
+                  );
+                }}
+                className={`px-1.5 py-0.5 transition-colors ${
+                  editModes.includes(m)
+                    ? "bg-muted text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                }`}
+              >
+                {m}
+              </button>
+            ))}
+          </div>
+        </>
+      )}
+      {showClear && !disabled && (
         <button
           onClick={onClear}
           className="text-xs text-muted-foreground hover:text-foreground transition-colors"
@@ -152,6 +263,15 @@ function specToNested(spec: Spec): Record<string, unknown> {
       node.children = el.children.map(resolve);
     }
 
+    if (el.slots && Object.keys(el.slots).length > 0) {
+      node.slots = Object.fromEntries(
+        Object.entries(el.slots).map(([slotName, childKeys]) => [
+          slotName,
+          childKeys.map(resolve),
+        ]),
+      );
+    }
+
     return node;
   }
 
@@ -173,6 +293,33 @@ const EXAMPLE_PROMPTS = [
   "Make a contact form",
 ];
 
+const JEV_EXAMPLE_PROMPTS = [
+  {
+    label: "Create a login form",
+    prompt:
+      'Create a login card titled "Sign in" with email, password, remember me, and a sign in button.',
+  },
+  {
+    label: "Create account settings",
+    prompt:
+      'Create an account settings card titled "Preferences" with full name, email, an email notifications switch, save and reset buttons side by side, and visible save status.',
+  },
+  {
+    label: "Design a user profile card",
+    prompt: "Design a user profile card",
+  },
+  {
+    label: "Build a sales dashboard",
+    prompt:
+      'Build a sales dashboard: heading "Sales overview", revenue, orders and new customers metrics in a three-column grid, then a weekly revenue chart and an order-status table.',
+  },
+  {
+    label: "Make a contact form",
+    prompt:
+      'Create a contact card titled "Contact us" with full name, email, topic, a message box, and a send message button.',
+  },
+];
+
 export function Playground() {
   const [versions, setVersions] = useState<Version[]>([]);
   const [selectedVersionId, setSelectedVersionId] = useState<string | null>(
@@ -186,12 +333,23 @@ export function Playground() {
   const [renderView, setRenderView] = useState<RenderView>("preview");
   const [mobileView, setMobileView] = useState<MobileView>("preview");
   const [versionsSheetOpen, setVersionsSheetOpen] = useState(false);
-  const [format, setFormat] = useState<StreamFormat>("jsonl");
+  const [preferredFormat, setFormat] = useState<StreamFormat>("jsonl");
+  const [model, setModel] = useState<PlaygroundModel>("default");
+  const format = model === "typesafe-ai/jev" ? "jsonl" : preferredFormat;
+  const examplePrompts =
+    model === "typesafe-ai/jev"
+      ? JEV_EXAMPLE_PROMPTS
+      : EXAMPLE_PROMPTS.map((prompt) => ({ label: prompt, prompt }));
   const [editModes, setEditModes] = useState<EditMode[]>(["patch"]);
   const inputRef = useRef<HTMLTextAreaElement>(null);
   const mobileInputRef = useRef<HTMLTextAreaElement>(null);
   const versionsEndRef = useRef<HTMLDivElement>(null);
 
+  useEffect(() => {
+    const input = inputRef.current;
+    if (input?.getClientRects().length) input.focus({ preventScroll: true });
+  }, []);
+
   // Track the currently generating version ID
   const generatingVersionIdRef = useRef<string | null>(null);
 
@@ -202,25 +360,20 @@ export function Playground() {
     spec: apiSpec,
     isStreaming,
     usage: streamUsage,
+    composition: streamComposition,
+    error: streamError,
     rawLines: streamRawLines,
     send,
     clear,
+    stop,
   } = usePlaygroundStream({
     api: "/api/generate",
+    model,
     format,
     editModes,
     onError: (err: Error) => {
       console.error("Generation error:", err);
       toast.error(err.message || "Generation failed. Please try again.");
-      if (generatingVersionIdRef.current) {
-        const erroredVersionId = generatingVersionIdRef.current;
-        setVersions((prev) =>
-          prev.map((v) =>
-            v.id === erroredVersionId ? { ...v, status: "error" as const } : v,
-          ),
-        );
-        generatingVersionIdRef.current = null;
-      }
     },
   });
 
@@ -247,27 +400,17 @@ export function Playground() {
     : (selectedVersion?.rawLines ?? []);
 
   // Keep the ref updated with the current tree for use in handleSubmit
-  if (
-    currentTree &&
-    currentTree.root &&
-    Object.keys(currentTree.elements).length > 0
-  ) {
-    currentTreeRef.current = currentTree;
-  }
+  currentTreeRef.current = currentTree?.root ? currentTree : null;
 
   // Scroll to bottom when versions change
   useEffect(() => {
-    versionsEndRef.current?.scrollIntoView({ behavior: "smooth" });
+    const container = versionsEndRef.current?.parentElement;
+    container?.scrollTo({ top: container.scrollHeight, behavior: "smooth" });
   }, [versions]);
 
   // Update version when streaming completes
   useEffect(() => {
-    if (
-      !isStreaming &&
-      apiSpec &&
-      apiSpec.root &&
-      generatingVersionIdRef.current
-    ) {
+    if (!isStreaming && generatingVersionIdRef.current) {
       const completedVersionId = generatingVersionIdRef.current;
       setVersions((prev) =>
         prev.map((v) =>
@@ -275,7 +418,23 @@ export function Playground() {
             ? {
                 ...v,
                 tree: apiSpec,
-                status: "complete" as const,
+                status: streamError
+                  ? apiSpec?.root
+                    ? ("partial" as const)
+                    : ("error" as const)
+                  : streamComposition?.stopReason === "limit"
+                    ? ("partial" as const)
+                    : streamComposition?.stopReason === "unavailable"
+                      ? ("unavailable" as const)
+                      : ("complete" as const),
+                message:
+                  streamError?.message ??
+                  (streamComposition?.stopReason === "limit"
+                    ? "Composition limit reached. The preview is partial."
+                    : streamComposition?.stopReason === "unavailable"
+                      ? "This request needs content or capabilities outside the prepared options."
+                      : undefined),
+                composition: streamComposition,
                 usage: streamUsage,
                 rawLines: streamRawLines,
               }
@@ -284,10 +443,18 @@ export function Playground() {
       );
       generatingVersionIdRef.current = null;
     }
-  }, [isStreaming, apiSpec, streamUsage, streamRawLines]);
+  }, [
+    isStreaming,
+    apiSpec,
+    streamUsage,
+    streamRawLines,
+    streamComposition,
+    streamError,
+  ]);
 
   const handleSubmit = useCallback(async () => {
-    if (!inputValue.trim() || isStreaming) return;
+    if (!inputValue.trim() || isStreaming || generatingVersionIdRef.current)
+      return;
 
     const newVersionId = Date.now().toString();
     const newVersion: Version = {
@@ -298,6 +465,8 @@ export function Playground() {
       usage: null,
       rawLines: [],
       format,
+      model,
+      composition: null,
     };
 
     generatingVersionIdRef.current = newVersionId;
@@ -307,7 +476,7 @@ export function Playground() {
 
     // Pass the current tree as context so the API can iterate on it
     await send(inputValue.trim(), { previousSpec: currentTreeRef.current });
-  }, [inputValue, isStreaming, send, format]);
+  }, [inputValue, isStreaming, send, format, model]);
 
   const handleKeyDown = useCallback(
     (e: React.KeyboardEvent) => {
@@ -373,21 +542,45 @@ export function Playground() {
 
       const propsStr = serializeProps(propsObj);
       const hasChildren = element.children && element.children.length > 0;
+      const hasSlots = element.slots && Object.keys(element.slots).length > 0;
 
-      if (!hasChildren) {
+      if (!hasChildren && !hasSlots) {
         return propsStr
           ? `${spaces}<${componentName} ${propsStr} />`
           : `${spaces}<${componentName} />`;
       }
 
       const lines: string[] = [];
-      lines.push(
-        propsStr
-          ? `${spaces}<${componentName} ${propsStr}>`
-          : `${spaces}<${componentName}>`,
-      );
+      if (hasSlots) {
+        lines.push(`${spaces}<${componentName}`);
+        if (propsStr) {
+          lines.push(`${spaces}  ${propsStr}`);
+        }
+        for (const [slotName, childKeys] of Object.entries(element.slots!)) {
+          const slotChildren = childKeys
+            .map((childKey) => generateJSX(childKey, indent + 2))
+            .filter(Boolean);
+          if (slotChildren.length === 0) continue;
+          lines.push(`${spaces}  ${slotName}={`);
+          if (slotChildren.length > 1) {
+            lines.push(`${spaces}    <>`);
+          }
+          lines.push(...slotChildren);
+          if (slotChildren.length > 1) {
+            lines.push(`${spaces}    </>`);
+          }
+          lines.push(`${spaces}  }`);
+        }
+        lines.push(`${spaces}>`);
+      } else {
+        lines.push(
+          propsStr
+            ? `${spaces}<${componentName} ${propsStr}>`
+            : `${spaces}<${componentName}>`,
+        );
+      }
 
-      for (const childKey of element.children!) {
+      for (const childKey of element.children ?? []) {
         lines.push(generateJSX(childKey, indent + 1));
       }
 
@@ -434,10 +627,12 @@ ${jsx}
         {versions.length === 0 ? (
           <div className="flex-1 flex flex-col items-center justify-center text-center px-4">
             <p className="text-sm text-muted-foreground mb-4">
-              Describe what you want to build, then iterate on it.
+              {model === "typesafe-ai/jev"
+                ? "Describe a UI to compose from the prepared options."
+                : "Describe what you want to build, then iterate on it."}
             </p>
             <div className="flex flex-wrap gap-2 justify-center">
-              {EXAMPLE_PROMPTS.map((prompt) => (
+              {examplePrompts.map(({ label, prompt }) => (
                 <button
                   key={prompt}
                   onMouseDown={(e) => {
@@ -460,7 +655,7 @@ ${jsx}
                   }}
                   className="text-xs px-2 py-1 rounded border border-border text-muted-foreground hover:text-foreground hover:border-foreground/30 transition-colors"
                 >
-                  {prompt}
+                  {label}
                 </button>
               ))}
             </div>
@@ -490,6 +685,7 @@ ${jsx}
                   <span className="text-xs text-red-500 shrink-0">failed</span>
                 )}
               </div>
+              <VersionDetails version={version} />
               {version.usage && (
                 <div className="mt-1 ml-6">
                   <span className="text-[10px] font-mono text-muted-foreground/60">
@@ -513,7 +709,10 @@ ${jsx}
         onMouseDown={(e) => {
           // Focus textarea unless clicking a button or the textarea itself
           const target = e.target as HTMLElement;
-          if (!target.closest("button") && target.tagName !== "TEXTAREA") {
+          if (
+            !target.closest("button, a, [role=combobox]") &&
+            target.tagName !== "TEXTAREA"
+          ) {
             e.preventDefault();
             inputRef.current?.focus();
           }
@@ -525,12 +724,15 @@ ${jsx}
           onChange={(e) => setInputValue(e.target.value)}
           onKeyDown={handleKeyDown}
           placeholder="Describe changes..."
+          maxLength={model === "typesafe-ai/jev" ? 1000 : undefined}
           className="w-full bg-background text-base sm:text-sm resize-none outline-none placeholder:text-muted-foreground/50"
           rows={2}
-          autoFocus
         />
-        <div className="flex justify-between items-center mt-2">
+        <div className="flex justify-between items-end gap-2 mt-2">
           <PlaygroundControls
+            model={model}
+            setModel={setModel}
+            disabled={isStreaming}
             format={format}
             setFormat={setFormat}
             editModes={editModes}
@@ -539,13 +741,15 @@ ${jsx}
             onClear={() => {
               setVersions([]);
               setSelectedVersionId(null);
+              generatingVersionIdRef.current = null;
+              currentTreeRef.current = null;
               clear();
             }}
           />
           {isStreaming ? (
             <button
-              onClick={() => clear()}
-              className="w-7 h-7 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors"
+              onClick={stop}
+              className="w-7 h-7 shrink-0 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors"
               aria-label="Stop"
             >
               <svg
@@ -562,7 +766,7 @@ ${jsx}
             <button
               onClick={handleSubmit}
               disabled={!inputValue.trim()}
-              className="w-7 h-7 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors disabled:opacity-30"
+              className="w-7 h-7 shrink-0 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors disabled:opacity-30"
               aria-label="Send"
             >
               <svg
@@ -835,8 +1039,12 @@ ${jsx}
       <div className="flex-1 overflow-auto">
         {renderView === "preview" ? (
           currentTree && currentTree.root ? (
-            <div className="w-full min-h-full flex items-center justify-center p-6">
+            <div
+              className="w-full min-h-full flex items-center justify-center p-6"
+              inert={isStreaming}
+            >
               <PlaygroundRenderer
+                key={selectedVersionId}
                 spec={currentTree}
                 data={currentTree.state}
                 loading={isStreaming}
@@ -863,8 +1071,6 @@ ${jsx}
 
   return (
     <div className="h-full flex flex-col">
-      <Header />
-
       {/* Desktop: 3-pane resizable layout */}
       <div className="hidden lg:flex flex-1 min-h-0">
         <ResizablePanelGroup className="flex-1">
@@ -1115,8 +1321,12 @@ ${jsx}
             />
           ) : mobileView === "preview" ? (
             currentTree && currentTree.root ? (
-              <div className="w-full min-h-full flex items-center justify-center p-6">
+              <div
+                className="w-full min-h-full flex items-center justify-center p-6"
+                inert={isStreaming}
+              >
                 <PlaygroundRenderer
+                  key={selectedVersionId}
                   spec={currentTree}
                   data={currentTree.state}
                   loading={isStreaming}
@@ -1131,10 +1341,12 @@ ${jsx}
                 ) : (
                   <>
                     <p className="text-sm text-muted-foreground mb-4">
-                      Describe what you want to build, then iterate on it.
+                      {model === "typesafe-ai/jev"
+                        ? "Describe a UI to compose from the prepared options."
+                        : "Describe what you want to build, then iterate on it."}
                     </p>
                     <div className="flex flex-wrap gap-2 justify-center">
-                      {EXAMPLE_PROMPTS.map((prompt) => (
+                      {examplePrompts.map(({ label, prompt }) => (
                         <button
                           key={prompt}
                           onMouseDown={(e) => {
@@ -1148,7 +1360,7 @@ ${jsx}
                           }}
                           className="text-xs px-2 py-1 rounded border border-border text-muted-foreground hover:text-foreground hover:border-foreground/30 transition-colors"
                         >
-                          {prompt}
+                          {label}
                         </button>
                       ))}
                     </div>
@@ -1169,10 +1381,13 @@ ${jsx}
 
         {/* Prompt input pinned to bottom */}
         <div
-          className="border-t border-border p-3 shrink-0 cursor-text"
+          className="border-t border-border p-3 pb-16 shrink-0 cursor-text"
           onMouseDown={(e) => {
             const target = e.target as HTMLElement;
-            if (!target.closest("button") && target.tagName !== "TEXTAREA") {
+            if (
+              !target.closest("button, a, [role=combobox]") &&
+              target.tagName !== "TEXTAREA"
+            ) {
               e.preventDefault();
               mobileInputRef.current?.focus();
             }
@@ -1184,11 +1399,15 @@ ${jsx}
             onChange={(e) => setInputValue(e.target.value)}
             onKeyDown={handleKeyDown}
             placeholder="Describe changes..."
+            maxLength={model === "typesafe-ai/jev" ? 1000 : undefined}
             className="w-full bg-background text-base resize-none outline-none placeholder:text-muted-foreground/50"
             rows={2}
           />
-          <div className="flex justify-between items-center mt-2">
+          <div className="flex justify-between items-end gap-2 mt-2">
             <PlaygroundControls
+              model={model}
+              setModel={setModel}
+              disabled={isStreaming}
               format={format}
               setFormat={setFormat}
               editModes={editModes}
@@ -1197,13 +1416,15 @@ ${jsx}
               onClear={() => {
                 setVersions([]);
                 setSelectedVersionId(null);
+                generatingVersionIdRef.current = null;
+                currentTreeRef.current = null;
                 clear();
               }}
             />
             {isStreaming ? (
               <button
-                onClick={() => clear()}
-                className="w-7 h-7 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors"
+                onClick={stop}
+                className="w-7 h-7 shrink-0 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors"
                 aria-label="Stop"
               >
                 <svg
@@ -1220,7 +1441,7 @@ ${jsx}
               <button
                 onClick={handleSubmit}
                 disabled={!inputValue.trim()}
-                className="w-7 h-7 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors disabled:opacity-30"
+                className="w-7 h-7 shrink-0 rounded-full bg-primary text-primary-foreground flex items-center justify-center hover:bg-primary/90 transition-colors disabled:opacity-30"
                 aria-label="Send"
               >
                 <svg
@@ -1275,6 +1496,7 @@ ${jsx}
                       </span>
                     )}
                   </div>
+                  <VersionDetails version={version} />
                   {version.usage && (
                     <div className="mt-1 ml-6">
                       <span className="text-[10px] font-mono text-muted-foreground/60">

apps/web/components/theme-provider.tsx

@@ -6,6 +6,7 @@ export function ThemeProvider({ children }: { children: React.ReactNode }) {
   return (
     <NextThemesProvider
       attribute="class"
+      value={{ dark: "dark-theme", light: "light-theme" }}
       defaultTheme="dark"
       enableSystem
       disableTransitionOnChange

apps/web/content/docs/a2ui.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/a2ui")
-
-# A2UI Integration
+---
+title: "A2UI Integration"
+---
 
 Use `@json-render/core` to support [A2UI](https://a2ui.org) natively.
 

apps/web/content/docs/adaptive-cards.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/adaptive-cards")
-
-# Adaptive Cards Integration
+---
+title: "Adaptive Cards Integration"
+---
 
 Use json-render to render [Microsoft Adaptive Cards](https://adaptivecards.io) natively.
 

apps/web/content/docs/ag-ui.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/ag-ui")
-
-# AG-UI Integration
+---
+title: "AG-UI Integration"
+---
 
 Use json-render to support [AG-UI](https://docs.copilotkit.ai/ag-ui) (Agent User Interaction Protocol) from CopilotKit.
 

apps/web/content/docs/ai-sdk.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/ai-sdk")
-
-# AI SDK Integration
+---
+title: "AI SDK Integration"
+---
 
 Use json-render with the [Vercel AI SDK](https://sdk.vercel.ai) for seamless streaming. json-render supports two modes: **Standalone** (standalone UI) and **Inline** (UI embedded in conversation). See [Generation Modes](/docs/generation-modes) for a detailed comparison.
 

apps/web/content/docs/api/codegen.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/codegen")
-
-# @json-render/codegen
+---
+title: "@json-render/codegen"
+---
 
 Utilities for generating code from UI trees.
 

apps/web/content/docs/api/core.mdx

@@ -1,10 +1,97 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/core")
-
-# @json-render/core
+---
+title: "@json-render/core"
+---
 
 Core types, schemas, and utilities.
 
+## experimental_composeSpec
+
+**Experimental, unreleased:** may change in any release. Pin exact versions when published; see [source-build setup and the full Jev guide](/docs/jev).
+
+```typescript
+import {
+  experimental_composeSpec,
+  type Experimental_CompositionCandidate,
+  type Experimental_CompositionEvaluator,
+  type Experimental_CompositionEvent,
+} from "@json-render/core";
+
+const events = experimental_composeSpec({
+  catalog,             // Standard flat Spec catalog
+  candidates,          // App-owned atomic elements
+  prompt,              // User request
+  evaluate,            // Experimental_CompositionEvaluator
+  initialState: {},    // Included in spec; not sent to evaluator
+  initialSpec,         // Optional selected version to edit; never mutated
+  elementDescriptions: {}, // Optional descriptions of existing element IDs
+  context: {},         // Explicitly shared evaluator context
+  strategy: "batch",  // Default for new trees; edits are sequential
+  maxElements: 32,     // Batched creation only, includes the root
+  maxSteps: 32,        // Evaluation calls, including terminal decisions
+  maxDepth: 8,         // Root depth is one
+  signal,              // AbortSignal, optional
+  instructions: { root: "", next: "", parent: "" }, // Appended guidance
+});
+```
+
+A candidate has `id`, `description`, `element`, optional `root` (default true), `maxUses` (default one), and `resource` (mutually exclusive variants). IDs start with a letter and contain only letters, digits, underscores, and hyphens. IDs must be unique; `finish` and `unavailable` are reserved. Elements accept `type`, `props`, optional `on`, and `visible`. The composer supplies children and named slots.
+
+Events are full detached snapshots. A `step` contains `spec` and `step`; `complete` contains nullable `spec`, `steps`, `elapsedMs`, nullable `inputTokens`, and `stopReason` (`finish`, `limit`, or `unavailable`). Each trace step contains `index`, `choice`, `description`, nullable `parent`/`slot`, nullable `confidence`/`parentConfidence`, `elapsedMs`, and nullable `inputTokens`. Batched steps also contain `answers`, keyed by question name, with each selected `choice` and optional confidence. Each trace represents one evaluation: batched timing and usage are counted once, not once per answer. Indexes start at zero. Completion is not a guarantee of semantic correctness.
+
+### Batched creation
+
+With no `initialSpec`, `strategy: "batch"` is the default. The first evaluation selects the root and required components together. Shared `resource` variants use one exclusive choice; reusable recipes use bounded counts that include the root when applicable. Root selection takes precedence over speculative membership for the same recipe/resource. The first snapshot includes all selected elements in catalog order under the root's default slot, or its first declared slot when there is no default.
+
+A second evaluation selects parents and sibling positions from the actual selected set. Equal positions retain catalog order. The combined tree must pass catalog, slot, depth, and tree validation before publication; a cycle or invalid layout throws and preserves the first snapshot as partial output. A single root or one child in a single slot needs no layout call. No separate finish call is made.
+
+`maxElements` limits batched creation, including the root. A truncated selection, insufficient depth for selected content, or a call budget that prevents required layout returns `limit`. Use `strategy: "sequential"` for one-operation-at-a-time creation. Edits always use the sequential protocol.
+
+Invalid configuration, out-of-set decisions, provider failures, and aborts throw. Previous snapshots remain usable as partial UI. Stopping iteration prevents further evaluation calls. A supplied signal also stops waiting for an evaluator that ignores cancellation; that evaluator must honor the signal to stop its underlying work.
+
+### Custom evaluators
+
+The composer is provider independent. An evaluator receives `state`, `questions`, and `signal`, then returns a selected criteria key for each question:
+
+```typescript
+const evaluate: Experimental_CompositionEvaluator = async ({ state, questions, signal }) => {
+  // Your adapter calls a decision model with this request.
+  const result = await yourEvaluator({ state, questions, signal });
+  return {
+    answers: result.answers, // { [questionName]: { choice: "offered_key", confidence: 0.9 } }
+    usage: { inputTokens: result.inputTokens }, // Optional
+  };
+};
+```
+
+Questions are records of `type: "choice"`, `instructions`, and `criteria` (choice key to description). Return an answer for every question and treat question/choice keys as opaque. Batched creation sends `root` and `select_*` questions, then `parent_*` and `order_*` questions. Sequential creation and edits use `next` to select an operation, `finish`, or `unavailable`, with `parent` when several attachment points exist. Existing adapters that only implement `next`/`parent` must opt into `strategy: "sequential"`. Confidence must be in [0, 1] when provided; input tokens must be a nonnegative integer.
+
+State contains `user_request` and explicit app `context`, plus capabilities/guidance during batched selection, `selected_elements` during layout, or `already_built` during sequential composition. Candidate descriptions and instructions are shared; raw state/props/binding values are not automatically included. See [validation and v1 limits](/docs/jev#validation-and-v1-limits).
+
+### Follow-up edits
+
+Pass `initialSpec` to edit an existing version. The composer validates and clones it, preserving unchanged elements, IDs, action bindings, and state. `initialState` explicitly overrides `initialSpec.state` when provided. Optional `elementDescriptions` maps existing IDs to descriptions shared with the evaluator; matching candidates supply the default description, otherwise only the component type is shared.
+
+Editing adds bounded operations: replace an element with an offered recipe, remove a non-root subtree, and move/reorder a subtree to an allowed slot/position. Replacements preserve children and are offered only when the new component can contain them. Moves cannot create cycles or exceed the depth limit. Seed specs with cycles, shared children, missing references, unreachable nodes, or unsupported expressions are rejected before evaluation.
+
+The `next` question offers opaque operation keys as well as candidate IDs. For replacement or movement, the following evaluation selects a recipe or destination, also through `next`. Both calls count toward `maxSteps`; the first emits an unchanged snapshot with its decision trace. `changes_made` supplies the edit trace alongside `already_built`. A budget limit, unavailable result, or cancellation may leave a selected edit unapplied. Existing elements exactly matching a recipe count toward `maxUses` and `resource`; removing/replacing them releases those limits.
+
+## experimental_createEvaluator
+
+**Experimental:** creates a server-side evaluator using Vercel AI Gateway's experimental v4 evaluation transport. No AI SDK dependency or provider constructor is required.
+
+```typescript
+import { experimental_createEvaluator } from "@json-render/core";
+
+const evaluate = experimental_createEvaluator({
+  apiKey: process.env.AI_GATEWAY_API_KEY!, // Required; keep server-side
+  model: "typesafe-ai/jev",               // Required, plain Gateway evaluation model ID
+  timeoutMs: 10_000,                      // Default, per evaluation
+  fetch: globalThis.fetch,               // Optional transport override
+});
+```
+
+The factory uses model-neutral naming and requires an explicit model. Jev is the current tested example; other models must support the Gateway choice-evaluation protocol. When using Jev, the Gateway team must permit TypeSafe AI. The adapter reports HTTP status on failure and rejects malformed/unoffered decisions. For Jev, it normalizes TypeSafe's native confidence rather than treating option probability as confidence. Confidence from other provider metadata is not yet normalized. Missing confidence and usage remain unknown. It does not retry automatically or estimate cost.
+
 ## defineCatalog
 
 Creates a type-safe catalog definition with schema validation.
@@ -339,17 +426,18 @@ setSpec({ ...applySpecPatch(spec, patch) });
 
 ### nestedToFlat
 
-Convert a nested element tree (with inline children) into the flat `Spec` format:
+Convert a nested element tree (with inline children and named slots) into the flat `Spec` format:
 
 ```typescript
 import { nestedToFlat } from '@json-render/core';
 
 const flat = nestedToFlat({
-  type: "Card",
-  props: { title: "Hello" },
-  children: [
-    { type: "Text", props: { content: "World" }, children: [] }
-  ],
+  type: "Layout",
+  props: {},
+  children: [{ type: "Text", props: { content: "Main" }, children: [] }],
+  slots: {
+    header: [{ type: "Heading", props: { text: "Header" }, children: [] }],
+  },
 });
 // { root: "el-0", elements: { "el-0": ..., "el-1": ... } }
 ```
@@ -462,14 +550,19 @@ const name2 = resolveDynamicValue({ $state: "/user/name" }, state);  // "Alice"
 
 ### findFormValue
 
+Read a value from resolved action parameters or state. A parameter value is literal, including strings with dots such as emails, URLs, and versions. Lookup order: a defined direct parameter, a parameter key ending in `.<fieldName>`, a matching flat state key, then a slash-delimited path in nested state.
+
 ```typescript
 import { findFormValue } from '@json-render/core';
 
-// Find form values regardless of path format
-// Checks: params.name, params["form.name"], state["form.name"], state.form.name
-const value = findFormValue("name", params, state);
+findFormValue("email", { email: "john.doe@example.com" }, {});
+findFormValue("email", { "form.email": "john.doe@example.com" }, {});
+findFormValue("email", {}, { "form.email": "john.doe@example.com" });
+findFormValue("/form/email", {}, { form: { email: "john.doe@example.com" } });
 ```
 
+For action bindings, use `{ $state: "/form/email" }` to read nested state: the action resolver passes the resulting value to the handler. A raw string like `"form.email"` in parameters is not a state reference. A bare `"email"` field name does not search `state.form.email`.
+
 ## buildUserPrompt
 
 Build structured user prompts for AI generation, with support for refinement and state context.
@@ -648,9 +741,10 @@ interface UIElement {
   type: string;
   props: Record<string, unknown>;
   children?: string[];          // Keys of child elements
+  slots?: Record<string, string[]>; // Named slots mapped to child keys
   visible?: VisibilityCondition;
   on?: Record<string, ActionBinding | ActionBinding[]>;  // Event bindings
-  repeat?: { statePath: string; key?: string };           // Repeat for arrays
+  repeat?: { statePath: string | { $item: string }; key?: string }; // Repeat for arrays
 }
 ```
 
@@ -666,7 +760,7 @@ interface Spec {
 }
 ```
 
-Elements are stored as a flat map with string keys. The tree structure is built by following the `children` arrays.
+Elements are stored as a flat map with string keys. The tree structure is built by following `children` and named `slots` references.
 
 ### ActionBinding
 

apps/web/content/docs/api/devtools-react.mdx

@@ -0,0 +1,58 @@
+---
+title: "@json-render/devtools-react"
+---
+
+React adapter for the json-render devtools. Drop-in `<JsonRenderDevtools />` component.
+
+See the [Devtools guide](/docs/devtools) for the drop-in walkthrough.
+
+## JsonRenderDevtools
+
+```tsx
+import { JsonRenderDevtools } from "@json-render/devtools-react";
+
+<JSONUIProvider registry={registry} handlers={handlers}>
+  <Renderer spec={spec} registry={registry} />
+  <JsonRenderDevtools spec={spec} catalog={catalog} messages={messages} />
+</JSONUIProvider>
+```
+
+### Props
+
+```tsx
+interface JsonRenderDevtoolsProps {
+  /** Current spec being rendered. */
+  spec?: Spec | null;
+  /** Catalog definition (required for the Catalog panel). */
+  catalog?: Catalog | null;
+  /** AI SDK useChat messages array. */
+  messages?: readonly UIMessage[];
+  /** Start the panel open. Default: false. */
+  initialOpen?: boolean;
+  /** Floating toggle position. */
+  position?: "bottom-right" | "bottom-left" | "right";
+  /** Toggle keybinding, or false to disable. Default: "mod+shift+j". */
+  hotkey?: string | false;
+  /** Ring buffer size. Default: 500. */
+  bufferSize?: number;
+  /** Fires for every devtools event. */
+  onEvent?: (evt: DevtoolsEvent) => void;
+}
+```
+
+In production builds the component renders `null`.
+
+## useJsonRenderDevtools
+
+```tsx
+import { useJsonRenderDevtools } from "@json-render/devtools-react";
+
+const devtools = useJsonRenderDevtools();
+devtools?.open();
+devtools?.toggle();
+devtools?.close();
+devtools?.clear();
+devtools?.recordEvent({ kind: "stream-text", at: Date.now(), text: "hi" });
+```
+
+Access the running devtools instance from anywhere in the React tree. Returns `null` in production or before the component has mounted.

apps/web/content/docs/api/devtools-solid.mdx

@@ -0,0 +1,37 @@
+---
+title: "@json-render/devtools-solid"
+---
+
+SolidJS adapter for the json-render devtools. Drop-in `<JsonRenderDevtools />` component.
+
+See the [Devtools guide](/docs/devtools) for the drop-in walkthrough.
+
+## JsonRenderDevtools
+
+```tsx
+import { JsonRenderDevtools } from "@json-render/devtools-solid";
+
+<JSONUIProvider registry={registry}>
+  <Renderer spec={spec()} registry={registry} />
+  <JsonRenderDevtools
+    spec={spec()}
+    catalog={catalog}
+    messages={messages()}
+  />
+</JSONUIProvider>
+```
+
+### Props
+
+Same shape as the React adapter:
+
+- `spec`
+- `catalog`
+- `messages`
+- `initialOpen`
+- `position`
+- `hotkey`
+- `bufferSize`
+- `onEvent`
+
+In production builds the component renders `null`.

apps/web/content/docs/api/devtools-svelte.mdx

@@ -0,0 +1,35 @@
+---
+title: "@json-render/devtools-svelte"
+---
+
+Svelte adapter for the json-render devtools. Drop-in `<JsonRenderDevtools />` component.
+
+See the [Devtools guide](/docs/devtools) for the drop-in walkthrough.
+
+## JsonRenderDevtools
+
+```svelte
+<script>
+  import { JsonRenderDevtools } from "@json-render/devtools-svelte";
+</script>
+
+<JSONUIProvider {registry}>
+  <Renderer {spec} {registry} />
+  <JsonRenderDevtools {spec} {catalog} {messages} />
+</JSONUIProvider>
+```
+
+### Props
+
+Same shape as the React adapter:
+
+- `spec`
+- `catalog`
+- `messages`
+- `initialOpen`
+- `position`
+- `hotkey`
+- `bufferSize`
+- `onEvent`
+
+In production builds the component renders nothing.

apps/web/content/docs/api/devtools-vue.mdx

@@ -0,0 +1,37 @@
+---
+title: "@json-render/devtools-vue"
+---
+
+Vue adapter for the json-render devtools. Drop-in `<JsonRenderDevtools />` component.
+
+See the [Devtools guide](/docs/devtools) for the drop-in walkthrough.
+
+## JsonRenderDevtools
+
+```vue
+<script setup>
+import { JsonRenderDevtools } from "@json-render/devtools-vue";
+</script>
+
+<template>
+  <JSONUIProvider :registry="registry">
+    <Renderer :spec="spec" :registry="registry" />
+    <JsonRenderDevtools :spec="spec" :catalog="catalog" :messages="messages" />
+  </JSONUIProvider>
+</template>
+```
+
+### Props
+
+Same shape as the React adapter:
+
+- `spec`
+- `catalog`
+- `messages`
+- `initialOpen`
+- `position`
+- `hotkey`
+- `bufferSize`
+- `onEvent`
+
+In production builds the component renders nothing.

apps/web/content/docs/api/devtools.mdx

@@ -0,0 +1,145 @@
+---
+title: "@json-render/devtools"
+---
+
+Framework-agnostic core for the json-render devtools — vanilla TS panel UI, event store, DOM picker, and stream tap utilities. Every framework-specific adapter package depends on this.
+
+Most users never import from this package directly. Pick the adapter that matches your renderer (`@json-render/devtools-react`, `@json-render/devtools-vue`, etc.) and drop the `<JsonRenderDevtools />` component into your app.
+
+See the [Devtools guide](/docs/devtools) for the drop-in walkthrough.
+
+## Event Store
+
+### createEventStore
+
+```ts
+function createEventStore(options?: { bufferSize?: number }): EventStore
+
+interface EventStore {
+  push: (event: DevtoolsEvent) => void;
+  snapshot: () => DevtoolsEvent[];
+  subscribe: (listener: () => void) => () => void;
+  clear: () => void;
+  size: () => number;
+}
+```
+
+Ring-buffered pub/sub of `DevtoolsEvent`. Shared by every panel and every stream tap.
+
+## Panel
+
+### createPanel
+
+```ts
+function createPanel(options: PanelOptions): PanelHandle
+
+interface PanelHandle {
+  open: () => void;
+  close: () => void;
+  toggle: () => void;
+  isOpen: () => boolean;
+  refresh: () => void;
+  destroy: () => void;
+}
+```
+
+Mount the panel into a host document. Adapters call this internally.
+
+### Panel tabs
+
+Each tab is a factory function that returns a `TabDef`:
+
+```ts
+import {
+  specTab,
+  stateTab,
+  actionsTab,
+  streamTab,
+  catalogTab,
+  pickerTab,
+} from "@json-render/devtools";
+```
+
+## Stream Taps
+
+### tapJsonRenderStream
+
+```ts
+function tapJsonRenderStream(
+  stream: ReadableStream<StreamChunk>,
+  events: EventStore,
+): ReadableStream<StreamChunk>
+```
+
+Mirror the spec patches flowing through a `pipeJsonRender` transform into a devtools event store. Returns the original stream unchanged — the tap just forks a copy.
+
+### tapYamlStream
+
+```ts
+function tapYamlStream(
+  stream: ReadableStream<StreamChunk>,
+  events: EventStore,
+): ReadableStream<StreamChunk>
+```
+
+YAML equivalent of `tapJsonRenderStream`.
+
+### scanMessageParts
+
+```ts
+function scanMessageParts(
+  parts: readonly DataPart[] | undefined,
+  events: EventStore,
+  seen: WeakSet<object>,
+): void
+```
+
+Client-side helper: scan an AI SDK message's `parts` array for spec data parts and push matching events into the store. Idempotent via `seen` — call it on every render of a chat UI.
+
+## Picker
+
+### startPicker
+
+```ts
+function startPicker(options: PickerOptions): PickerSession | null
+
+interface PickerOptions {
+  onPick: (key: string) => void;
+  onCancel?: () => void;
+}
+```
+
+Start a DOM picker session. Hovering paints an outline on any element carrying `data-jr-key`; clicking fires `onPick` with the spec key. Returns `null` in environments without a DOM.
+
+### findElementByKey / highlightElement
+
+```ts
+function findElementByKey(key: string): Element | null
+function highlightElement(key: string, durationMs?: number): void
+```
+
+Look up the live DOM node for a spec element key, or briefly paint an outline around it.
+
+## Types
+
+### DevtoolsEvent
+
+```ts
+type DevtoolsEvent =
+  | { kind: "spec-changed"; at: number; spec: Spec }
+  | { kind: "state-set"; at: number; path: string; prev: unknown; next: unknown }
+  | { kind: "action-dispatched"; at: number; id: string; name: string; params?: unknown }
+  | { kind: "action-settled"; at: number; id: string; ok: boolean; result?: unknown; error?: string; durationMs: number }
+  | { kind: "stream-patch"; at: number; patch: JsonPatch; source: "json" | "yaml" }
+  | { kind: "stream-text"; at: number; text: string }
+  | { kind: "stream-usage"; at: number; usage: TokenUsage }
+  | { kind: "stream-lifecycle"; at: number; phase: "start" | "end"; ok?: boolean };
+```
+
+### isProduction
+
+```ts
+function isProduction(): boolean
+```
+
+`true` when `process.env.NODE_ENV === "production"`. Adapters use this to short-circuit to a null render.

apps/web/content/docs/api/directives.mdx

@@ -0,0 +1,406 @@
+---
+title: "@json-render/directives"
+---
+
+Pre-built custom directives for `@json-render/core`. Drop them into your catalog and renderer to add formatting, math, string manipulation, and i18n.
+
+## Install
+
+```bash
+npm install @json-render/directives
+```
+
+## Quick Start
+
+```typescript
+import { standardDirectives } from '@json-render/directives';
+
+// Wire into prompt generation
+const prompt = catalog.prompt({ directives: standardDirectives });
+
+// Wire into the renderer
+<JSONUIProvider spec={spec} directives={standardDirectives}>
+  ...
+</JSONUIProvider>
+```
+
+To add factory directives like `createI18nDirective`, spread the array:
+
+```typescript
+import { standardDirectives, createI18nDirective } from '@json-render/directives';
+
+const directives = [...standardDirectives, createI18nDirective(config)];
+```
+
+## Directives
+
+### `$format` — Locale-aware value formatting
+
+Formats values using `Intl` formatters. Supports `date`, `currency`, `number`, and `percent`.
+
+```json
+{ "$format": "currency", "value": { "$state": "/cart/total" }, "currency": "USD" }
+```
+
+```json
+{ "$format": "date", "value": { "$state": "/user/createdAt" } }
+```
+
+```json
+{ "$format": "number", "value": 1234567, "notation": "compact" }
+```
+
+```json
+{ "$format": "percent", "value": 0.75 }
+```
+
+Relative dates are also supported:
+
+```json
+{ "$format": "date", "value": { "$state": "/post/createdAt" }, "style": "relative" }
+```
+
+This returns strings like `"3h ago"`, `"2d from now"`, or `"just now"`.
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$format</code></td>
+      <td><code>{'\"date\" | \"currency\" | \"number\" | \"percent\"'}</code></td>
+      <td>Format type.</td>
+    </tr>
+    <tr>
+      <td><code>value</code></td>
+      <td><code>unknown</code></td>
+      <td>Value to format. Accepts any dynamic expression.</td>
+    </tr>
+    <tr>
+      <td><code>locale</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Locale for formatting (e.g. <code>"en-US"</code>).</td>
+    </tr>
+    <tr>
+      <td><code>currency</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Currency code for <code>"currency"</code> format. Default: <code>"USD"</code>.</td>
+    </tr>
+    <tr>
+      <td><code>notation</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Notation for <code>"number"</code> format (e.g. <code>"compact"</code>).</td>
+    </tr>
+    <tr>
+      <td><code>style</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Set to <code>"relative"</code> for relative date formatting.</td>
+    </tr>
+    <tr>
+      <td><code>options</code></td>
+      <td><code>{'Record<string, unknown>'}</code></td>
+      <td>Optional. Extra <code>Intl</code> formatter options.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `$math` — Arithmetic operations
+
+Performs arithmetic on one or two operands. Operands accept any dynamic expression.
+
+```json
+{ "$math": "add", "a": { "$state": "/subtotal" }, "b": { "$state": "/tax" } }
+```
+
+```json
+{ "$math": "round", "a": 3.7 }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$math</code></td>
+      <td><code>{'\"add\" | \"subtract\" | \"multiply\" | \"divide\" | \"mod\" | \"min\" | \"max\" | \"round\" | \"floor\" | \"ceil\" | \"abs\"'}</code></td>
+      <td>Operation to perform.</td>
+    </tr>
+    <tr>
+      <td><code>a</code></td>
+      <td><code>unknown</code></td>
+      <td>First operand. Defaults to <code>0</code> if missing.</td>
+    </tr>
+    <tr>
+      <td><code>b</code></td>
+      <td><code>unknown</code></td>
+      <td>Second operand (binary ops only). Defaults to <code>0</code> if missing.</td>
+    </tr>
+  </tbody>
+</table>
+
+Unary operations (`round`, `floor`, `ceil`, `abs`) only use `a`. Division by zero returns `0`.
+
+### `$concat` — String concatenation
+
+Concatenates multiple values into a single string. Each element is resolved then joined.
+
+```json
+{ "$concat": [{ "$state": "/user/firstName" }, " ", { "$state": "/user/lastName" }] }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$concat</code></td>
+      <td><code>{'unknown[]'}</code></td>
+      <td>Array of values to concatenate. Each is resolved, converted to string, and joined.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `$count` — Array/string length
+
+Returns the length of an array or string. Returns `0` for other types.
+
+```json
+{ "$count": { "$state": "/cart/items" } }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$count</code></td>
+      <td><code>unknown</code></td>
+      <td>Value to count. Accepts arrays and strings.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `$truncate` — Text truncation
+
+Truncates text to a maximum length with a configurable suffix.
+
+```json
+{ "$truncate": { "$state": "/post/body" }, "length": 140, "suffix": "..." }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$truncate</code></td>
+      <td><code>unknown</code></td>
+      <td>Value to truncate.</td>
+    </tr>
+    <tr>
+      <td><code>length</code></td>
+      <td><code>number</code></td>
+      <td>Optional. Max character length. Default: <code>100</code>.</td>
+    </tr>
+    <tr>
+      <td><code>suffix</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Suffix to append when truncated. Default: <code>"..."</code>.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `$pluralize` — Singular/plural forms
+
+Selects a singular, plural, or zero form based on a count.
+
+```json
+{ "$pluralize": { "$state": "/cart/itemCount" }, "one": "item", "other": "items", "zero": "no items" }
+```
+
+Output: `"3 items"`, `"1 item"`, or `"no items"`.
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$pluralize</code></td>
+      <td><code>unknown</code></td>
+      <td>Count value. Accepts dynamic expressions.</td>
+    </tr>
+    <tr>
+      <td><code>one</code></td>
+      <td><code>string</code></td>
+      <td>Singular form label.</td>
+    </tr>
+    <tr>
+      <td><code>other</code></td>
+      <td><code>string</code></td>
+      <td>Plural form label.</td>
+    </tr>
+    <tr>
+      <td><code>zero</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Label for count of zero. If omitted, uses <code>"0 {'<other>'}"</code>.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `$join` — Join array elements
+
+Joins array elements with a separator string.
+
+```json
+{ "$join": { "$state": "/tags" }, "separator": ", " }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$join</code></td>
+      <td><code>unknown</code></td>
+      <td>Array to join. Non-array values are converted to string.</td>
+    </tr>
+    <tr>
+      <td><code>separator</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Separator between elements. Default: <code>", "</code>.</td>
+    </tr>
+  </tbody>
+</table>
+
+### `createI18nDirective` — Internationalization
+
+Factory function that creates a `$t` directive for translations with `{'{{param}}'}` interpolation.
+
+```typescript
+import { createI18nDirective } from '@json-render/directives';
+
+const tDirective = createI18nDirective({
+  locale: 'en',
+  messages: {
+    en: { "greeting": "Hello, {'{{name}}'}!", "checkout.submit": "Place Order" },
+    es: { "greeting": "Hola, {'{{name}}'}!", "checkout.submit": "Realizar Pedido" },
+  },
+  fallbackLocale: 'en',
+});
+```
+
+Usage in specs:
+
+```json
+{ "$t": "checkout.submit" }
+```
+
+```json
+{ "$t": "greeting", "params": { "name": { "$state": "/user/name" } } }
+```
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>$t</code></td>
+      <td><code>string</code></td>
+      <td>Translation key.</td>
+    </tr>
+    <tr>
+      <td><code>params</code></td>
+      <td><code>{'Record<string, unknown>'}</code></td>
+      <td>Optional. Interpolation parameters. Values accept dynamic expressions.</td>
+    </tr>
+  </tbody>
+</table>
+
+#### `I18nConfig`
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>locale</code></td>
+      <td><code>string</code></td>
+      <td>Current locale (e.g. <code>"en"</code>).</td>
+    </tr>
+    <tr>
+      <td><code>messages</code></td>
+      <td><code>{'Record<string, Record<string, string>>'}</code></td>
+      <td>Map of locale to key-value translation pairs.</td>
+    </tr>
+    <tr>
+      <td><code>fallbackLocale</code></td>
+      <td><code>string</code></td>
+      <td>Optional. Fallback locale when a key is missing in the current locale.</td>
+    </tr>
+  </tbody>
+</table>
+
+## Composition
+
+Directives compose naturally. Each resolver calls `resolvePropValue` on its inputs, so you can nest directives:
+
+```json
+{
+  "$format": "currency",
+  "value": { "$math": "multiply", "a": { "$state": "/price" }, "b": { "$state": "/qty" } },
+  "currency": "USD"
+}
+```
+
+```json
+{
+  "$pluralize": { "$count": { "$state": "/items" } },
+  "one": "item",
+  "other": "items"
+}
+```

apps/web/content/docs/api/image.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/image")
-
-# @json-render/image
+---
+title: "@json-render/image"
+---
 
 Image renderer. Turn JSON specs into SVG and PNG images using [Satori](https://github.com/vercel/satori).
 

apps/web/content/docs/api/ink.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/ink")
-
-# @json-render/ink
+---
+title: "@json-render/ink"
+---
 
 Terminal renderer for [Ink](https://github.com/vadimdemedes/ink) with multiple standard components, providers, hooks, and streaming support.
 

apps/web/content/docs/api/jotai.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/jotai")
-
-# @json-render/jotai
+---
+title: "@json-render/jotai"
+---
 
 Jotai adapter for json-render's `StateStore` interface.
 

apps/web/content/docs/api/mcp.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/mcp")
-
-# @json-render/mcp
+---
+title: "@json-render/mcp"
+---
 
 MCP Apps integration for json-render. Serve json-render UIs as interactive [MCP Apps](https://modelcontextprotocol.io/docs/extensions/apps) inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients.
 

apps/web/content/docs/api/meta.json

@@ -0,0 +1,34 @@
+{
+  "title": "API Reference",
+  "pages": [
+    "core",
+    "react",
+    "next",
+    "tanstack-start",
+    "react-pdf",
+    "react-email",
+    "shadcn",
+    "shadcn-svelte",
+    "react-native",
+    "image",
+    "remotion",
+    "ink",
+    "vue",
+    "svelte",
+    "solid",
+    "react-three-fiber",
+    "directives",
+    "codegen",
+    "devtools",
+    "devtools-react",
+    "devtools-vue",
+    "devtools-svelte",
+    "devtools-solid",
+    "mcp",
+    "redux",
+    "zustand",
+    "jotai",
+    "xstate",
+    "yaml"
+  ]
+}

apps/web/content/docs/api/next.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/next")
-
-# @json-render/next
+---
+title: "@json-render/next"
+---
 
 Next.js renderer. JSON becomes full Next.js applications with routes, layouts, metadata, and SSR.
 

apps/web/content/docs/api/react-email.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/react-email")
-
-# @json-render/react-email
+---
+title: "@json-render/react-email"
+---
 
 React Email renderer. Turn JSON specs into HTML or plain-text emails using `@react-email/components` and `@react-email/render`.
 

apps/web/content/docs/api/react-native.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/react-native")
-
-# @json-render/react-native
+---
+title: "@json-render/react-native"
+---
 
 React Native renderer with standard components, providers, and hooks.
 

apps/web/content/docs/api/react-pdf.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/react-pdf")
-
-# @json-render/react-pdf
+---
+title: "@json-render/react-pdf"
+---
 
 PDF document renderer. Turn JSON specs into PDFs using `@react-pdf/renderer`.
 

apps/web/content/docs/api/react-three-fiber.mdx

@@ -1,9 +1,8 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/react-three-fiber")
+---
+title: "@json-render/react-three-fiber"
+---
 
-# @json-render/react-three-fiber
-
-React Three Fiber renderer for json-render. 19 built-in 3D components for meshes, lights, models, environments, text, cameras, and controls.
+React Three Fiber renderer for json-render. 20 built-in 3D components for meshes, lights, models, gaussian splats, environments, text, cameras, and controls.
 
 ## Installation
 
@@ -283,6 +282,11 @@ All primitives share: <code>position</code>, <code>rotation</code>, <code>scale<
 <td>Camera controls</td>
 <td><code>enableDamping</code>, <code>enableZoom</code>, <code>autoRotate</code></td>
 </tr>
+<tr>
+<td><code>GaussianSplat</code></td>
+<td>Gaussian splat (.splat/.ply) loader</td>
+<td><code>src</code>, <code>position</code>, <code>rotation</code>, <code>scale</code>, <code>alphaHash</code>, <code>toneMapped</code></td>
+</tr>
 </tbody>
 </table>
 

apps/web/content/docs/api/react.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/react")
-
-# @json-render/react
+---
+title: "@json-render/react"
+---
 
 React components, providers, and hooks.
 

apps/web/content/docs/api/redux.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/redux")
-
-# @json-render/redux
+---
+title: "@json-render/redux"
+---
 
 Redux / Redux Toolkit adapter for json-render's `StateStore` interface.
 

apps/web/content/docs/api/remotion.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/remotion")
-
-# @json-render/remotion
+---
+title: "@json-render/remotion"
+---
 
 Remotion video renderer. Turn JSON timeline specs into video compositions.
 

apps/web/content/docs/api/shadcn-svelte.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/shadcn-svelte")
-
-# @json-render/shadcn-svelte
+---
+title: "@json-render/shadcn-svelte"
+---
 
 Pre-built [shadcn-svelte](https://www.shadcn-svelte.com/) components for json-render. 36 components built on Svelte 5 + Tailwind CSS, ready to use with `defineCatalog` and `defineRegistry`.
 

apps/web/content/docs/api/shadcn.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/shadcn")
-
-# @json-render/shadcn
+---
+title: "@json-render/shadcn"
+---
 
 Pre-built [shadcn/ui](https://ui.shadcn.com/) components for json-render. 36 components built on Radix UI + Tailwind CSS, ready to use with `defineCatalog` and `defineRegistry`.
 

apps/web/content/docs/api/solid.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata";
-export const metadata = pageMetadata("docs/api/solid");
-
-# @json-render/solid
+---
+title: "@json-render/solid"
+---
 
 SolidJS components, providers, and hooks for rendering json-render specs.
 

apps/web/content/docs/api/svelte.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/svelte")
-
-# @json-render/svelte
+---
+title: "@json-render/svelte"
+---
 
 Svelte 5 components, providers, and helpers for rendering json-render specs.
 

apps/web/content/docs/api/tanstack-start.mdx

@@ -0,0 +1,391 @@
+---
+title: "@json-render/tanstack-start"
+---
+
+TanStack Start renderer for JSON-defined applications with routes, layouts,
+head metadata, SSR loaders, prerender paths, and client navigation.
+
+## Installation
+
+```bash
+npm install @json-render/core @json-render/react @json-render/tanstack-start
+```
+
+## schema
+
+Use the Start application schema to generate full multi-page specs.
+
+```typescript
+import { defineCatalog } from "@json-render/core";
+import {
+  schema,
+  startComponentDefinitions,
+} from "@json-render/tanstack-start/server";
+import { z } from "zod";
+
+const catalog = defineCatalog(schema, {
+  components: {
+    ...startComponentDefinitions,
+    Card: {
+      props: z.object({ title: z.string() }),
+      description: "Card container",
+    },
+    NavBar: {
+      props: z.object({}),
+      slots: ["default"],
+      description: "Application navigation",
+    },
+  },
+  actions: {},
+});
+```
+
+The generation prompt teaches TanStack Router's `$param` and `$` splat route
+syntax, reusable layouts, escaped JSON Patch route keys, and the built-in
+`Slot`, `Link`, and `navigate` capabilities.
+
+Include `startComponentDefinitions` in the catalog so generated `Slot` and
+`Link` elements pass validation. `PageRenderer` supplies their React
+implementations automatically.
+
+## createStartApp
+
+Create helpers for a TanStack Start splat route.
+
+```typescript
+import { createStartApp } from "@json-render/tanstack-start/server";
+
+export const { getPageData, getHead, getStaticPaths } = createStartApp({
+  spec,
+  loaders: {
+    post: async ({ slug }) => ({
+      post: await getPost(slug as string),
+    }),
+  },
+});
+```
+
+### Options
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>
+        <code>spec</code>
+      </td>
+      <td>
+        <code>
+          {"StartAppSpec | (() => StartAppSpec | Promise<StartAppSpec>)"}
+        </code>
+      </td>
+      <td>A static application spec or an async spec factory</td>
+    </tr>
+    <tr>
+      <td>
+        <code>loaders</code>
+      </td>
+      <td>
+        <code>{"Record<string, LoaderFn>"}</code>
+      </td>
+      <td>Named data loaders referenced by route specs</td>
+    </tr>
+  </tbody>
+</table>
+
+### Returns
+
+<table>
+  <thead>
+    <tr>
+      <th>Helper</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>
+        <code>getPageData</code>
+      </td>
+      <td>
+        Matches a pathname, runs its loader, and returns serializable page and
+        layout data
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <code>getHead</code>
+      </td>
+      <td>
+        Returns TanStack Router <code>meta</code> and <code>links</code>{" "}
+        descriptors
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <code>getStaticPaths</code>
+      </td>
+      <td>Returns concrete paths for TanStack Start prerendering</td>
+    </tr>
+  </tbody>
+</table>
+
+State is merged in this order: application state, layout state, page state,
+then loader data. Later sources override earlier values.
+
+## StartAppSpec
+
+```typescript
+interface StartAppSpec {
+  metadata?: StartMetadata;
+  routes: Record<string, StartRouteSpec>;
+  layouts?: Record<string, Spec>;
+  state?: Record<string, unknown>;
+}
+```
+
+Each route requires a `page` spec and can select a layout, metadata, a named
+loader, loading/error/not-found specs, and static parameters.
+
+### Route Patterns
+
+<table>
+  <thead>
+    <tr>
+      <th>Pattern</th>
+      <th>Example</th>
+      <th>Params</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>
+        <code>/</code>
+      </td>
+      <td>
+        <code>/</code>
+      </td>
+      <td>
+        <code>{"{}"}</code>
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <code>/about</code>
+      </td>
+      <td>
+        <code>/about</code>
+      </td>
+      <td>
+        <code>{"{}"}</code>
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <code>{"/blog/$slug"}</code>
+      </td>
+      <td>
+        <code>/blog/hello</code>
+      </td>
+      <td>
+        <code>{'{ slug: "hello" }'}</code>
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <code>{"/docs/$"}</code>
+      </td>
+      <td>
+        <code>/docs/guides/intro</code>
+      </td>
+      <td>
+        <code>{'{ _splat: "guides/intro" }'}</code>
+      </td>
+    </tr>
+  </tbody>
+</table>
+
+Loader parameters are URL-decoded before they reach named loaders. Splat
+content is a slash-delimited string under `_splat`. Parameter values supplied
+through `staticParams` are URL-encoded in the paths returned by
+`getStaticPaths()`.
+
+Route matching treats trailing slashes as optional and accepts both encoded and
+decoded pathname representations. This keeps loader data and route metadata in
+sync for static paths containing spaces or non-ASCII characters.
+
+For prerendered dynamic routes, provide `staticParams`:
+
+```typescript
+routes: {
+  '/blog/$slug': {
+    page,
+    staticParams: [{ slug: 'hello' }, { slug: 'world' }],
+  },
+  '/docs/$': {
+    page: docsPage,
+    staticParams: [{ _splat: 'guides/intro' }],
+  },
+}
+```
+
+Map `getStaticPaths()` into TanStack Start's top-level `pages` configuration:
+
+```typescript
+const pages = (await getStaticPaths()).map((path) => ({ path }));
+```
+
+## TanStack Route Setup
+
+Wire the helpers to a file-based `$` splat route:
+
+```tsx
+// src/routes/$.tsx
+import { createFileRoute, notFound } from "@tanstack/react-router";
+import {
+  PageRenderer,
+  StartErrorBoundary,
+  StartLoading,
+  StartNotFound,
+} from "@json-render/tanstack-start";
+import { getHead, getPageData } from "@/lib/json-app";
+
+export const Route = createFileRoute("/$")({
+  loader: async ({ location }) => {
+    const data = await getPageData({ pathname: location.pathname });
+    if (!data) throw notFound();
+    return data;
+  },
+  head: ({ match }) => getHead({ pathname: match.pathname }),
+  component: Page,
+  pendingComponent: StartLoading,
+  errorComponent: StartErrorBoundary,
+  notFoundComponent: StartNotFound,
+});
+
+function Page() {
+  return <PageRenderer {...Route.useLoaderData()} />;
+}
+```
+
+TanStack Router loaders are isomorphic. When a spec factory or named loader
+uses database clients, credentials, or server-only imports, invoke
+`getPageData` and `getHead` inside a TanStack Start `createServerFn` and call
+that server function from the route loader.
+
+## StartAppProvider
+
+Provide component implementations and action handlers around the root
+`Outlet`. Render `HeadContent` for route metadata.
+
+```tsx
+import {
+  createRootRoute,
+  HeadContent,
+  Outlet,
+  Scripts,
+} from "@tanstack/react-router";
+import { StartAppProvider } from "@json-render/tanstack-start";
+import { spec } from "@/lib/spec";
+
+export const Route = createRootRoute({
+  component: () => (
+    <html lang="en">
+      <head>
+        <HeadContent />
+      </head>
+      <body>
+        <StartAppProvider
+          registry={registry}
+          handlers={handlers}
+          spec={spec}
+        >
+          <Outlet />
+        </StartAppProvider>
+        <Scripts />
+      </body>
+    </html>
+  ),
+});
+```
+
+Passing `spec` lets `StartLoading`, `StartErrorBoundary`, and `StartNotFound`
+automatically select the matched route's fallback specs. Their explicit
+`loadingSpec`, `errorSpec`, and `notFoundSpec` props take precedence. For a
+server-only application spec, omit `spec` and pass client-safe fallback specs
+explicitly.
+
+Pass named functions through `functions` when props use `$computed`:
+
+```tsx
+<StartAppProvider
+  registry={registry}
+  spec={spec}
+  functions={{ uppercase: ({ value }) => String(value).toUpperCase() }}
+>
+  <Outlet />
+</StartAppProvider>
+```
+
+## Built-ins
+
+- `Slot` inserts page content into a JSON-defined layout.
+- `Link` wraps TanStack Router's `Link`; generated specs use an `href` prop.
+- `navigate` performs client-side navigation from action bindings.
+- `StartLoading`, `StartErrorBoundary`, and `StartNotFound` resolve the matched
+  route's fallback specs when they are used as TanStack Router boundary
+  components and the provider receives `spec`.
+
+The default `StartErrorBoundary` fallback invalidates the router and reruns the
+failed loader when the user selects **Try again**.
+
+`Slot` and `Link` are automatically added to the page registry.
+
+## Server Utilities
+
+```typescript
+import {
+  collectStaticPaths,
+  matchRoute,
+  metadataToHead,
+  resolveMetadata,
+  splatToPath,
+} from "@json-render/tanstack-start/server";
+```
+
+## Entry Points
+
+<table>
+  <thead>
+    <tr>
+      <th>Import</th>
+      <th>Contents</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>
+        <code>@json-render/tanstack-start</code>
+      </td>
+      <td>Provider, page renderer, Link, and route fallback components</td>
+    </tr>
+    <tr>
+      <td>
+        <code>@json-render/tanstack-start/server</code>
+      </td>
+      <td>App factory, schema, matcher, metadata, and prerender helpers</td>
+    </tr>
+    <tr>
+      <td>
+        <code>@json-render/tanstack-start/catalog</code>
+      </td>
+      <td>Server-safe definitions for built-in Slot and Link components</td>
+    </tr>
+  </tbody>
+</table>

apps/web/content/docs/api/vue.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/vue")
-
-# @json-render/vue
+---
+title: "@json-render/vue"
+---
 
 Vue 3 components, providers, and composables.
 
@@ -95,7 +94,7 @@ store.set("/count", 1);
 
 ## defineRegistry
 
-Create a type-safe component registry from a catalog. Components receive `props`, `children`, `emit`, `on`, and `loading` with catalog-inferred types.
+Create a type-safe component registry from a catalog. Components receive `props`, `children`, `slots`, `emit`, `on`, and `loading` with catalog-inferred types.
 
 When the catalog declares actions, the `actions` field is required. When the catalog has no actions (e.g. `actions: {}`), the field is optional. When passing stubs, any `async () => {}` is sufficient.
 
@@ -105,8 +104,12 @@ import { defineRegistry } from "@json-render/vue";
 
 const { registry } = defineRegistry(catalog, {
   components: {
-    Card: ({ props, children }) =>
-      h("div", { class: "card" }, [h("h3", null, props.title), children]),
+    Layout: ({ slots }) =>
+      h("div", { class: "layout" }, [
+        h("header", null, slots.header?.()),
+        h("main", null, slots.default?.()),
+        h("footer", null, slots.footer?.()),
+      ]),
     Button: ({ props, emit }) =>
       h("button", { onClick: () => emit("press") }, props.label),
   },
@@ -136,11 +139,12 @@ const { registry } = defineRegistry(catalog, {
 ### Component Props (via defineRegistry)
 
 ```typescript
-import type { VNode } from "vue";
+import type { Slots, VNode } from "vue";
 
 interface ComponentContext<P> {
   props: P;                          // Typed props from catalog
   children?: VNode | VNode[];        // Rendered children (for container components)
+  slots: Slots;                      // Vue-native slot functions
   emit: (event: string) => void;     // Emit a named event (always defined)
   on: (event: string) => EventHandle; // Get event handle with metadata
   loading?: boolean;
@@ -154,6 +158,22 @@ interface EventHandle {
 }
 ```
 
+Use `children` for the default slot. For other slots declared by the catalog, add a top-level `slots` map to the spec element:
+
+```json
+{
+  "type": "Layout",
+  "props": {},
+  "children": ["main-content"],
+  "slots": {
+    "header": ["page-heading"],
+    "footer": ["page-actions"]
+  }
+}
+```
+
+The component renders these regions with Vue's native slot functions: `slots.header?.()`, `slots.footer?.()`, and so on. `slots.default?.()` renders the spec's `children`; `children` is a convenience alias for that rendered result. In the JSON spec, keep default content in `children` rather than adding a `default` entry to `slots`.
+
 Use `emit("press")` for simple event firing. Use `on("click")` when you need metadata like `shouldPreventDefault`:
 
 ```typescript

apps/web/content/docs/api/xstate.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/xstate")
-
-# @json-render/xstate
+---
+title: "@json-render/xstate"
+---
 
 [XState Store](https://stately.ai/docs/xstate-store) adapter for json-render's `StateStore` interface.
 

apps/web/content/docs/api/yaml.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/yaml")
-
-# @json-render/yaml
+---
+title: "@json-render/yaml"
+---
 
 YAML wire format for json-render. Progressive rendering and surgical edits via streaming YAML.
 

apps/web/content/docs/api/zustand.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/api/zustand")
-
-# @json-render/zustand
+---
+title: "@json-render/zustand"
+---
 
 Zustand adapter for json-render's `StateStore` interface.
 

apps/web/content/docs/catalog.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/catalog")
-
-# Catalog
+---
+title: "Catalog"
+---
 
 The catalog defines what AI can generate. It's your guardrail.
 
@@ -18,9 +17,9 @@ A catalog is the vocabulary for your UI. While the [schema](/docs/schemas) defin
 `defineCatalog` is from `@json-render/core`. The `schema` import comes from your platform package (`@json-render/react` or `@json-render/react-native`) and defines the element structure the catalog targets. The catalog definition itself is framework-agnostic.
 
 ```typescript
-import { defineCatalog } from '@json-render/core';
-import { schema } from '@json-render/react/schema'; // or '@json-render/react-native/schema'
-import { z } from 'zod';
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/react/schema"; // or '@json-render/react-native/schema'
+import { z } from "zod";
 
 const catalog = defineCatalog(schema, {
   components: {
@@ -29,35 +28,35 @@ const catalog = defineCatalog(schema, {
       props: z.object({
         title: z.string(),
         description: z.string().nullable(),
-        padding: z.enum(['sm', 'md', 'lg']).nullable(),
+        padding: z.enum(["sm", "md", "lg"]).nullable(),
       }),
       slots: ["default"], // Can contain other components
       description: "Container card for grouping content",
     },
-    
+
     Metric: {
       props: z.object({
         label: z.string(),
         value: z.union([z.string(), z.number()]),
-        format: z.enum(['currency', 'percent', 'number']),
+        format: z.enum(["currency", "percent", "number"]),
       }),
       description: "Display a single metric value",
     },
   },
-  
+
   actions: {
     submit_form: {
       params: z.object({
         formId: z.string(),
       }),
-      description: 'Submit a form',
+      description: "Submit a form",
     },
-    
+
     export_data: {
       params: z.object({
-        format: z.enum(['csv', 'pdf', 'json']),
+        format: z.enum(["csv", "pdf", "json"]),
       }),
-      description: 'Export data in various formats',
+      description: "Export data in various formats",
     },
   },
 });
@@ -70,12 +69,22 @@ Each component in the catalog has:
 ```typescript
 {
   props: z.object({...}),  // Zod schema for props (use .nullable() for optional)
-  slots?: string[],        // Named slots for children (e.g., ["default"])
+  slots?: string[],        // Available slots (e.g., ["default", "header", "footer"])
   description?: string,    // Help AI understand when to use it
 }
 ```
 
-Use `slots: ["default"]` for components that can contain children. The slot name corresponds to where child elements are rendered.
+Use `"default"` for regular children. Add named slots when a component places content in multiple regions:
+
+```typescript
+Layout: {
+  props: z.object({}),
+  slots: ["default", "header", "footer"],
+  description: "Page layout with header, content, and footer regions",
+}
+```
+
+React specs use `children` for the default slot and a `slots` object for the other names.
 
 ## Generating AI Prompts
 

apps/web/content/docs/changelog.mdx

@@ -1,13 +1,367 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/changelog")
-
-# Changelog
+---
+title: "Changelog"
+---
 
 Notable changes and updates to json-render.
 
+## v0.21.0
+
+September 18, 2026
+
+### New: TanStack Start Renderer
+
+Added `@json-render/tanstack-start` for JSON-defined applications with file-based routes, reusable layouts, SSR loaders, head metadata, prerender paths, client navigation, and route fallbacks.
+
+See the [TanStack Start API reference](/docs/api/tanstack-start) for setup and route configuration.
+
+### New: Experimental Jev Composition
+
+Added `experimental_composeSpec` and `experimental_createEvaluator` to `@json-render/core`. Apps can provide their own catalogs and bounded component candidates, then stream validated compositions through an evaluation model. The playground now includes a Jev model option and supports iterative composition edits.
+
+These APIs are experimental and may change in any release. See the [Jev guide](/docs/jev) for the source-build workflow, examples, and current limitations.
+
+### Improved: Vue Named Slots
+
+Vue registries now support catalog-declared named slots alongside the default `children` slot.
+
+### Fixed: React Streaming Stability
+
+Stabilized streamed React renders and added coverage for incomplete streamed props and nested prop identities.
+
+---
+
+## v0.20.0
+
+August 15, 2026
+
+### New: Named Slots for React
+
+React components can now declare named slots such as `header` and `footer`, while `children` remains the default slot. Named slots are preserved through validation, streaming, nested conversion, code export, playground views, and Devtools navigation.
+
+This work builds on the original named slots contribution by @wotnak.
+
+```tsx
+const catalog = defineCatalog(schema, {
+  components: {
+    Layout: {
+      props: z.object({}),
+      slots: ["default", "header", "footer"],
+    },
+  },
+});
+
+const { registry } = defineRegistry(catalog, {
+  components: {
+    Layout: ({ children, slots }) => (
+      <section>
+        <header>{slots?.header}</header>
+        <main>{children}</main>
+        <footer>{slots?.footer}</footer>
+      </section>
+    ),
+  },
+});
+```
+
+### New: Nested Repeats
+
+`repeat.statePath` now accepts item-relative paths such as `{ "$item": "employees" }`. Nested data can be rendered across React, React Native, React Email, React PDF, Image, Ink, Solid, Svelte, and Vue.
+
+This work builds on the original nested repeats contribution by @tmchow.
+
+```json
+{
+  "type": "Table",
+  "repeat": { "statePath": { "$item": "employees" }, "key": "id" },
+  "children": ["employee-row"],
+  "props": {}
+}
+```
+
+### New: Harness Chat Example
+
+Added a complete Next.js example using the AI SDK 7 harness adapter, agent delegation, sandbox transport, and json-render components.
+
+### Fixed: Chained Action Params
+
+Named `onSuccess` and `onError` actions now receive their configured `params` across core and all renderer bridges. Custom renderer bridges must now accept an `ActionBinding` in the core `executeAction` callback instead of a bare action name.
+
+### Improved: Spec Validation and Compatibility
+
+Element visibility remains optional across Zod 4 versions. Autofix now prunes dangling child references, validation reports malformed visibility conditions, and repeated items can be filtered safely.
+
+### Improved: Release Toolchain
+
+The workspace now requires Node.js 24 and pnpm 11, enforces package engine checks, and applies a minimum package release age.
+
+---
+
+## v0.19.0
+
+May 6, 2026
+
+### New: Custom Directives API
+
+`@json-render/core` now supports custom directives via `defineDirective`, letting you declare new JSON shapes (like `$format`, `$math`) that resolve to computed values at render time. Directives compose naturally -- nest `$format` over `$math` over `$state` and they resolve inside-out. All four renderers (React, Vue, Svelte, Solid) have built-in directive resolution.
+
+### New: `@json-render/directives`
+
+New package shipping seven ready-made directives: `$format` (date, currency, number, percent via `Intl`), `$math` (arithmetic and rounding), `$concat`, `$count`, `$truncate`, `$pluralize`, and `$join`. Also exports `createI18nDirective` for `$t` translation keys with interpolation, and `standardDirectives` for one-line registration.
+
+```bash
+npm install @json-render/directives
+```
+
+```tsx
+import { standardDirectives } from "@json-render/directives";
+
+const catalog = createCatalog({
+  directives: standardDirectives,
+  // ...
+});
+```
+
+See the [Directives guide](/docs/directives) and the [API reference](/docs/api/directives) for details.
+
+---
+
+## v0.18.0
+
+April 17, 2026
+
+### New: Devtools
+
+Five new packages for inspecting json-render apps in the browser:
+
+- `@json-render/devtools` -- framework-agnostic core
+- `@json-render/devtools-react`
+- `@json-render/devtools-vue`
+- `@json-render/devtools-svelte`
+- `@json-render/devtools-solid`
+
+Drop `<JsonRenderDevtools />` into your app to get a shadow-DOM-isolated panel with six tabs (Spec, State, Actions, Stream, Catalog, Pick), a DOM picker that maps clicked elements back to spec keys via `data-jr-key`, and a capped event store. Toggle with the floating button or `Cmd`/`Ctrl` + `Shift` + `J`. Tree-shakes to `null` in production.
+
+```bash
+npm install @json-render/devtools-react
+```
+
+```tsx
+import { JsonRenderDevtools } from "@json-render/devtools-react";
+
+<JsonRenderDevtools />
+```
+
+See the [Devtools guide](/docs/devtools) and the [API reference](/docs/api/devtools) for details.
+
+### New: Devtools Example
+
+New `examples/devtools` Next.js demo showing the full devtools panel wired up to an AI chat endpoint and a component catalog.
+
+### New: Action Observer and Devtools Flag in Core
+
+`@json-render/core` now exposes an action observer and a devtools enablement flag that framework adapters use to mirror actions and stream events into the panel.
+
+### Fixed: Zod 4 Schema Formatting
+
+`formatZodType` now correctly handles `z.record()`, `z.default()`, and `z.literal()` types from Zod 4, which previously produced incorrect or empty output in generated prompts and schemas.
+
+---
+
+## v0.17.0
+
+April 10, 2026
+
+### New: Gaussian Splatting
+
+Added `GaussianSplat` component to `@json-render/react-three-fiber`, bringing the component count to 20. Composable with all existing R3F components (lights, controls, post-processing) via drei's Splat loader.
+
+### New: R3F Gaussian Splatting Example
+
+Demo app with five scenes: splat showroom, splat with primitives, multi-splat, post-processing effects, and animated floating splat.
+
+### New: Standalone gsplat Example
+
+Experimental demo app showcasing Gaussian Splatting with gsplat.js (no Three.js dependency), featuring scene selector, live JSON spec viewer, and progress indicator.
+
+### Improved: AI Output Quality
+
+Improved prompt output and schema generation for more reliable AI-generated specs.
+
+---
+
+## v0.16.0
+
+March 27, 2026
+
+### New: `@json-render/next`
+
+Next.js renderer that turns JSON specs into full Next.js applications with routes, layouts, SSR, metadata, data loaders, and static generation. Client and server entry points at `@json-render/next` and `@json-render/next/server`. Includes built-in `Link`, `Slot`, error boundary, loading, and not-found components.
+
+```bash
+npm install @json-render/next
+```
+
+### New: `@json-render/shadcn-svelte`
+
+Pre-built shadcn-svelte components for json-render Svelte apps. 36 components built on Svelte 5 + Tailwind CSS with state binding, validation, and action support. Server-safe catalog at `@json-render/shadcn-svelte/catalog`.
+
+```bash
+npm install @json-render/shadcn-svelte
+```
+
+### Improved: Release Process
+
+Switched from Changesets to a manual single-PR release workflow with changelog markers and automatic npm publish on version bump.
+
+---
+
+## v0.15.0
+
+March 23, 2026
+
+### New: `@json-render/ink`
+
+Terminal renderer for json-render. JSON becomes terminal UIs powered by [Ink](https://github.com/vadimdemedes/ink). Stream AI-generated specs directly to the terminal with `useUIStream`.
+
+```bash
+npm install @json-render/ink
+```
+
+### Improved: YAML Format Support in `buildUserPrompt`
+
+`buildUserPrompt` now accepts `format` and `serializer` options, enabling YAML as a wire format alongside JSON.
+
+---
+
+## v0.14.0
+
+March 13, 2026
+
+### New: `@json-render/yaml`
+
+YAML wire format for json-render. Includes streaming YAML parser, `yamlPrompt()` for system prompts, and AI SDK transform (`pipeYamlRender`) as a drop-in alternative to JSONL streaming. Supports four fence types: `yaml-spec`, `yaml-edit`, `yaml-patch`, and `diff`.
+
+```bash
+npm install @json-render/yaml
+```
+
+### New: Universal Edit Modes
+
+Three strategies for multi-turn spec refinement in `@json-render/core`:
+
+- **Patch** -- RFC 6902 JSON Patch
+- **Merge** -- RFC 7396 Merge Patch
+- **Diff** -- Unified diff
+
+New `editModes` option on `buildUserPrompt()` and `PromptOptions`. New helpers: `deepMergeSpec()`, `diffToPatches()`, `buildEditUserPrompt()`, `buildEditInstructions()`, `isNonEmptySpec()`.
+
+### Improved: Playground
+
+Format toggle (JSONL / YAML), edit mode picker (patch / merge / diff), and token usage display with prompt caching stats.
+
+### Improved: Prompt Caching
+
+Generate API uses Anthropic ephemeral cache control for system prompts.
+
+---
+
+## v0.13.0
+
+March 12, 2026
+
+### New: `@json-render/solid`
+
+SolidJS renderer for json-render. JSON becomes Solid components with reactive rendering, schema export, and full catalog support.
+
+```bash
+npm install @json-render/core @json-render/solid
+```
+
+### New: `@json-render/react-three-fiber`
+
+React Three Fiber renderer for json-render. JSON becomes 3D scenes with 19 built-in components for meshes, lights, models, environments, text, cameras, and controls.
+
+```bash
+npm install @json-render/react-three-fiber
+```
+
+### Improved: Strict JSON Schema Mode
+
+`catalog.jsonSchema({ strict: true })` produces a JSON Schema subset compatible with LLM structured output APIs (OpenAI, Google Gemini, Anthropic). Ensures `additionalProperties: false` on every object and all properties listed in `required`.
+
+---
+
+## v0.12.1
+
+March 11, 2026
+
+### Changed: Generation Mode Renames
+
+Renamed generation modes from `"generate"` / `"chat"` to `"standalone"` / `"inline"`. The old names still work but emit a deprecation warning.
+
+### Fixed: MCP React Duplicate Module Error
+
+Resolved React duplicate module error (`useRef` returning null) in `@json-render/mcp` by adding `resolve.dedupe` Vite configuration. Added `./build-app-html` export entry point.
+
+---
+
+## v0.12.0
+
+March 6, 2026
+
+### New: `@json-render/svelte`
+
+Svelte 5 renderer with runes-based reactivity. Full support for data binding, visibility, actions, validation, watchers, streaming, and repeat scopes. Includes `defineRegistry`, `Renderer`, `schema`, composables, and context providers.
+
+```bash
+npm install @json-render/core @json-render/svelte
+```
+
+### New: `@json-render/react-email`
+
+React Email renderer for generating HTML and plain-text emails from JSON specs. 17 standard components (Html, Head, Body, Container, Section, Row, Column, Heading, Text, Link, Button, Image, Hr, Preview, Markdown). Server-side `renderToHtml` / `renderToPlainText` APIs.
+
+```bash
+npm install @json-render/react-email
+```
+
+### New: `@json-render/mcp`
+
+MCP Apps integration that serves json-render UIs as interactive apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients. `createMcpApp` server factory, `useJsonRenderApp` React hook for iframes, and `buildAppHtml` utility.
+
+```bash
+npm install @json-render/mcp
+```
+
+---
+
+## v0.11.0
+
+February 27, 2026
+
+### New: `@json-render/image`
+
+Server-side image renderer powered by Satori. Turns the same `{ root, elements }` spec format into SVG or PNG output for OG images, social cards, and banners.
+
+```bash
+npm install @json-render/image
+```
+
+```typescript
+import { renderToSvg, renderToPng } from "@json-render/image/render";
+import { standardComponentDefinitions } from "@json-render/image/catalog";
+
+const svg = await renderToSvg(spec, { width: 1200, height: 630 });
+const png = await renderToPng(spec, { width: 1200, height: 630 });
+```
+
+9 standard components: Frame, Box, Row, Column, Heading, Text, Image, Divider, Spacer. Server-safe import path at `@json-render/image/server`.
+
+---
+
 ## v0.10.0
 
-February 2026
+February 25, 2026
 
 ### New: `@json-render/vue`
 
@@ -120,7 +474,7 @@ All form components now support `checks` and `validateOn` props:
 
 ## v0.9.1
 
-February 2026
+February 24, 2026
 
 ### Fixed: Install failure due to private dependency
 
@@ -130,7 +484,7 @@ February 2026
 
 ## v0.9.0
 
-February 2026
+February 24, 2026
 
 ### New: External State Store
 
@@ -184,7 +538,7 @@ Fixed safely resolving the inner type for Zod arrays in schema introspection, pr
 
 ## v0.8.0
 
-February 2026
+February 20, 2026
 
 ### New: `@json-render/react-pdf`
 
@@ -246,7 +600,7 @@ Supports custom catalogs with `defineRegistry`, server-safe imports via `@json-r
 
 ## v0.7.0
 
-February 2026
+February 17, 2026
 
 ### New: `@json-render/shadcn`
 
@@ -337,7 +691,7 @@ Action bindings now support a `preventDefault` boolean field, allowing the LLM t
 
 ## v0.6.0
 
-February 2026
+February 13, 2026
 
 ### New: Chat Mode (Inline GenUI)
 
@@ -479,7 +833,7 @@ See the [Migration Guide](/docs/migration) for detailed upgrade instructions.
 
 ## v0.5.0
 
-February 2026
+February 9, 2026
 
 ### New: @json-render/react-native
 
@@ -598,7 +952,7 @@ Schema prompts now include streaming best practices, repeat/list examples, and s
 
 ## v0.4.0
 
-February 2026
+February 5, 2026
 
 ### New: Custom Schema System
 
@@ -733,7 +1087,7 @@ The dashboard example is now a full-featured accounting dashboard with:
 
 ## v0.3.0
 
-January 2026
+January 20, 2026
 
 Internal release with codegen foundations.
 
@@ -747,7 +1101,7 @@ Internal release with codegen foundations.
 
 ## v0.2.0
 
-January 2026
+January 14, 2026
 
 Initial public release.
 

apps/web/content/docs/code-export.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/code-export")
-
-# Code Export
+---
+title: "Code Export"
+---
 
 Export generated UI as standalone code for your framework.
 

apps/web/content/docs/computed-values.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/computed-values")
-
-# Computed Values
+---
+title: "Computed Values"
+---
 
 Derive dynamic prop values using registered functions or string templates.
 

apps/web/content/docs/custom-schema.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/custom-schema")
-
-# Custom Schema & Renderer
+---
+title: "Custom Schema & Renderer"
+---
 
 Build your own schema and renderer with `@json-render/core`.
 

apps/web/content/docs/data-binding.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/data-binding")
-
-# Data Binding
+---
+title: "Data Binding"
+---
 
 Connect UI elements to dynamic data using expressions in your JSON specs.
 
@@ -126,7 +125,7 @@ The `repeat` field on an element renders its children once per item in a state a
 }
 ```
 
-- `repeat.statePath` — JSON Pointer to the state array
+- `repeat.statePath`: root JSON Pointer to the state array, or `{ "$item": "field" }` for an array on the enclosing repeat item
 - `repeat.key` — field name on each item to use as a stable key for rendering
 
 Inside `todo-item`, `{ "$item": "title" }` reads the `title` field from whichever array item is currently being rendered. `{ "$index": true }` would return `0` for the first item, `1` for the second, and so on.

apps/web/content/docs/devtools.mdx

@@ -0,0 +1,206 @@
+---
+title: "Devtools"
+---
+
+A drop-in inspector panel for any json-render app. See the spec tree, edit state inline, watch dispatched actions, follow stream patches live, browse your catalog, and pick DOM elements to map them back to spec keys.
+
+Production-safe: the component tree-shakes to a null render when `NODE_ENV === "production"`.
+
+## Install
+
+Pick the adapter that matches your renderer.
+
+### React
+
+```bash
+npm install @json-render/devtools @json-render/devtools-react
+```
+
+### Vue
+
+```bash
+npm install @json-render/devtools @json-render/devtools-vue
+```
+
+### Svelte
+
+```bash
+npm install @json-render/devtools @json-render/devtools-svelte
+```
+
+### Solid
+
+```bash
+npm install @json-render/devtools @json-render/devtools-solid
+```
+
+## Quick Start
+
+Drop `<JsonRenderDevtools />` anywhere inside your existing `<JSONUIProvider>` (or the equivalent provider tree).
+
+```tsx
+// React
+import { JsonRenderDevtools } from "@json-render/devtools-react";
+
+<JSONUIProvider registry={registry} handlers={handlers}>
+  <Renderer spec={spec} registry={registry} />
+  <JsonRenderDevtools spec={spec} catalog={catalog} />
+</JSONUIProvider>
+```
+
+That's it. A floating toggle appears in the bottom-right corner. Click it, or press <kbd>Ctrl</kbd>/<kbd>Cmd</kbd> + <kbd>Shift</kbd> + <kbd>J</kbd>, to open the drawer.
+
+### Chat apps (AI SDK)
+
+When you're using `@ai-sdk/react`'s `useChat`, pass the `messages` prop so the Stream tab captures spec patches as they arrive:
+
+```tsx
+<JsonRenderDevtools
+  spec={spec}
+  catalog={catalog}
+  messages={messages}
+/>
+```
+
+## Panels
+
+<table>
+  <thead>
+    <tr><th>Tab</th><th>What it shows</th></tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><strong>Spec</strong></td>
+      <td>Element tree rooted at <code>spec.root</code>. Expand to walk children. Selecting an element fills a detail pane with its full props, visibility condition, event bindings, watchers, and any issues reported by <code>validateSpec</code>.</td>
+    </tr>
+    <tr>
+      <td><strong>State</strong></td>
+      <td>Every leaf path in the state model listed via <code>flattenToPointers</code>. Click a value to edit inline — writes go through <code>store.set</code>, so conditional elements and computed props re-evaluate immediately.</td>
+    </tr>
+    <tr>
+      <td><strong>Actions</strong></td>
+      <td>Timeline of dispatched actions: name, params, result or error, duration. Newest first. Expand a row for the full JSON payload.</td>
+    </tr>
+    <tr>
+      <td><strong>Stream</strong></td>
+      <td>Patches, text chunks, token usage, and lifecycle markers from the AI generation stream. Grouped by generation.</td>
+    </tr>
+    <tr>
+      <td><strong>Catalog</strong></td>
+      <td>Components and actions declared in your catalog with prop chips and type hints.</td>
+    </tr>
+    <tr>
+      <td><strong>Pick</strong></td>
+      <td>Click any element in the page to surface its entry in the Spec tab. Works because the renderer transparently tags each element with <code>data-jr-key</code> while devtools is mounted.</td>
+    </tr>
+  </tbody>
+</table>
+
+## Props
+
+<table>
+  <thead>
+    <tr><th>Prop</th><th>Type</th><th>Default</th><th>Description</th></tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>spec</code></td>
+      <td><code>Spec | null</code></td>
+      <td><code>null</code></td>
+      <td>The spec currently being rendered.</td>
+    </tr>
+    <tr>
+      <td><code>catalog</code></td>
+      <td><code>Catalog | null</code></td>
+      <td><code>null</code></td>
+      <td>Catalog definition — required for the Catalog panel.</td>
+    </tr>
+    <tr>
+      <td><code>messages</code></td>
+      <td><code>UIMessage[]</code></td>
+      <td><code>undefined</code></td>
+      <td>AI SDK <code>useChat</code> messages. Scanned for spec data parts and streamed into the Stream panel.</td>
+    </tr>
+    <tr>
+      <td><code>initialOpen</code></td>
+      <td><code>boolean</code></td>
+      <td><code>false</code></td>
+      <td>Start the drawer open.</td>
+    </tr>
+    <tr>
+      <td><code>position</code></td>
+      <td><code>"bottom-right" | "bottom-left" | "right"</code></td>
+      <td><code>"bottom-right"</code></td>
+      <td>Floating toggle button position.</td>
+    </tr>
+    <tr>
+      <td><code>hotkey</code></td>
+      <td><code>string | false</code></td>
+      <td><code>"mod+shift+j"</code></td>
+      <td>Keyboard shortcut. Use <code>mod</code> for Cmd on macOS / Ctrl elsewhere. Pass <code>false</code> to disable.</td>
+    </tr>
+    <tr>
+      <td><code>bufferSize</code></td>
+      <td><code>number</code></td>
+      <td><code>500</code></td>
+      <td>Max events retained in the ring buffer.</td>
+    </tr>
+    <tr>
+      <td><code>onEvent</code></td>
+      <td><code>(evt: DevtoolsEvent) =&gt; void</code></td>
+      <td><code>undefined</code></td>
+      <td>Optional tap — fires for every event as it is recorded. Useful for forwarding to analytics.</td>
+    </tr>
+  </tbody>
+</table>
+
+## Production Safety
+
+The component renders `null` when `process.env.NODE_ENV === "production"`. Bundlers fold the constant check so the panel's code tree-shakes out of production builds.
+
+If you want extra certainty, gate the import behind an env check:
+
+```tsx
+import dynamic from "next/dynamic";
+
+const JsonRenderDevtools = dynamic(
+  () =>
+    import("@json-render/devtools-react").then((m) => ({
+      default: m.JsonRenderDevtools,
+    })),
+  { ssr: false, loading: () => null },
+);
+```
+
+## Advanced
+
+### Imperative controls
+
+Use `useJsonRenderDevtools()` (React adapter only) to open / close the panel or record custom events from anywhere in the app:
+
+```tsx
+import { useJsonRenderDevtools } from "@json-render/devtools-react";
+
+function DebugButton() {
+  const devtools = useJsonRenderDevtools();
+  return (
+    <button onClick={() => devtools?.toggle()}>Toggle devtools</button>
+  );
+}
+```
+
+### Server-side stream tap
+
+Capture stream events before they reach the client. Useful for server logs:
+
+```ts
+import { tapJsonRenderStream } from "@json-render/devtools";
+
+const tapped = tapJsonRenderStream(
+  result.toUIMessageStream(),
+  serverEventStore,
+);
+writer.merge(pipeJsonRender(tapped));
+```
+
+The `@json-render/devtools` core package exports `tapJsonRenderStream` and `tapYamlStream` for this pattern.

apps/web/content/docs/directives.mdx

@@ -0,0 +1,123 @@
+---
+title: "Directives"
+---
+
+Extend the spec language with custom `$`-prefixed dynamic values. Directives let you add formatting, math, string manipulation, i18n, and any other transformation without modifying core.
+
+## Overview
+
+A directive is a user-defined dynamic value expression, like `$state` or `$computed`, but defined in userland. Each directive has a `$`-prefixed name, a Zod schema for validation, and a resolver function.
+
+```json
+{
+  "type": "Text",
+  "props": {
+    "text": {
+      "$format": "currency",
+      "value": { "$state": "/cart/total" },
+      "currency": "USD"
+    }
+  },
+  "children": []
+}
+```
+
+## Defining a Directive
+
+Use `defineDirective` from `@json-render/core`:
+
+```typescript
+import { defineDirective, resolvePropValue } from '@json-render/core';
+import { z } from 'zod';
+
+const doubleDirective = defineDirective({
+  name: '$double',
+  description: 'Double a numeric value.',
+  schema: z.object({
+    $double: z.unknown(),
+  }),
+  resolve(value, ctx) {
+    const resolved = resolvePropValue(value.$double, ctx);
+    return (resolved as number) * 2;
+  },
+});
+```
+
+The `description` field is optional. When generating prompts, the directive's schema fields are auto-described from the Zod schema; the `description` adds short behavioral context the schema can't express.
+
+## Wiring Directives
+
+Pass directives to both the renderer (for runtime resolution) and the catalog prompt (for AI generation).
+
+### Runtime
+
+```tsx
+import { JSONUIProvider, Renderer } from '@json-render/react';
+import { standardDirectives } from '@json-render/directives';
+
+<JSONUIProvider registry={registry} directives={standardDirectives}>
+  <Renderer spec={spec} registry={registry} />
+</JSONUIProvider>
+```
+
+Or with `createRenderer`:
+
+```tsx
+const MyRenderer = createRenderer(catalog, components);
+
+<MyRenderer spec={spec} directives={directives} />
+```
+
+All four renderers (React, Vue, Svelte, Solid) accept the `directives` prop on their provider and `createRenderer` output.
+
+### Prompt Generation
+
+```typescript
+const prompt = catalog.prompt({ directives });
+```
+
+Each directive's schema is auto-described in the "CUSTOM DYNAMIC VALUES" section of the system prompt. The optional `description` field adds behavioral context inline.
+
+## Pre-built Directives
+
+The `@json-render/directives` package ships ready-to-use directives:
+
+```typescript
+import { standardDirectives, createI18nDirective } from '@json-render/directives';
+```
+
+`standardDirectives` includes `$format`, `$math`, `$concat`, `$count`, `$truncate`, `$pluralize`, and `$join`. Add factory directives by spreading:
+
+```typescript
+const directives = [...standardDirectives, createI18nDirective(config)];
+```
+
+See the [API reference](/docs/api/directives) for details on each directive.
+
+## Composition
+
+Directives compose naturally. Each resolver calls `resolvePropValue` on its inputs, so directives can wrap other directives or built-in expressions like `$state`:
+
+```json
+{
+  "$format": "currency",
+  "value": {
+    "$math": "multiply",
+    "a": { "$state": "/price" },
+    "b": { "$state": "/qty" }
+  },
+  "currency": "USD"
+}
+```
+
+This resolves inside-out: `$state` reads from state, `$math` multiplies the values, and `$format` formats the result as currency.
+
+## Built-in Precedence
+
+Built-in expressions (`$state`, `$computed`, `$cond`, `$template`, etc.) always take precedence over custom directives. `defineDirective` throws if you try to register a name that conflicts with a built-in key.
+
+## Next
+
+- [API Reference](/docs/api/directives) — full directive reference
+- [Computed Values](/docs/computed-values) — `$computed` and `$template` expressions
+- [Data Binding](/docs/data-binding) — `$state`, `$item`, and binding expressions

apps/web/content/docs/generation-modes.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/generation-modes")
-
-# Generation Modes
+---
+title: "Generation Modes"
+---
 
 json-render supports two modes for AI-generated UI: **Standalone mode** for standalone UI and **Inline mode** for inline UI within a conversation.
 

apps/web/content/docs/index.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs")
-
-# Introduction
+---
+title: "Introduction"
+---
 
 json-render is a framework for **Generative UI** — AI-generated interfaces that are safe, predictable, and render natively on any platform.
 

apps/web/content/docs/installation.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/installation")
-
-# Installation
+---
+title: "Installation"
+---
 
 Install the core package plus your renderer of choice.
 

apps/web/content/docs/jev.mdx

@@ -0,0 +1,181 @@
+---
+title: "Jev (Experimental)"
+---
+**Experimental:** `experimental_composeSpec` and `experimental_createEvaluator` are reusable APIs in `@json-render/core`. Like AI SDK's experimental APIs, names prefixed with `experimental_` or `Experimental_` may change in any release. Pin exact package versions (no `^` or `~`) and review release notes before upgrading.
+
+**Availability:** these APIs are unreleased. You can try the source build below before they appear in a published npm version.
+
+Open the [playground](/playground), select **jev** in the **default / jev** toggle, and send a request. Hover or focus the Jev option with its info icon for details about the experiment. Or use your own catalog in your app. [Share feedback](https://github.com/vercel-labs/json-render/issues/new) with your catalog, candidates, request, resulting spec, and expected behavior. Remove private data from reproductions.
+
+## Why use it?
+
+The public API is model-neutral: `experimental_createEvaluator` takes an explicit Gateway evaluation model ID. Jev is the current tested example.
+
+Jev is a decision model from TypeSafe AI. It chooses among discrete options instead of writing free-form text. json-render turns those choices into a normal flat `Spec`, which your existing renderer, component registry, and action handlers can use.
+
+Your app supplies atomic element candidates: component names, concrete props, state bindings, and allowed action bindings. Jev selects which to include, their order, and their placement. The platform controls the available capabilities and design system. The composer never executes actions.
+
+New trees use batched composition by default. One evaluation selects the root and required components together, and immediately emits a validated preview containing content. A second evaluation arranges the selected elements when needed. This avoids one network round trip per component. The first preview uses catalog order and the root's default (or first declared) slot; the final layout can move elements. Root selection takes precedence over speculative membership for the same recipe/resource, and equal sibling positions retain catalog order. Inconsistent combined layouts throw, retaining the first preview as partial output. Set `strategy: "sequential"` for one-operation-at-a-time creation; follow-up edits remain sequential.
+
+A catalog alone is not enough for Jev: open-ended string props and data still need values. Build candidates from your records, localized copy, form definitions, or prepared content. Jev cannot invent missing prose or data.
+
+UI composition and data can stay separate: bind candidate props to `initialState` with `$state`, or construct candidates from the current records for each request. Jev chooses the component tree, grouping, and order; no complete page template is required. Each candidate is a configured component instance, so the model can only select the chart types, field configurations, and layout variants you offer. For example, supplying a revenue BarGraph alone does not let it choose a LineGraph; supply both candidates with a shared `resource` to offer that choice.
+
+## Try it in your app
+
+From a checkout containing this feature, build and pack core:
+
+```sh
+pnpm install --frozen-lockfile
+pnpm --filter @json-render/core build
+pnpm --filter @json-render/core pack --pack-destination /tmp/json-render-preview
+```
+
+Install the resulting `.tgz` file in your app with `pnpm add /absolute/path/to/the-file.tgz`. Keep your renderer and other json-render packages on the same version as the checkout. Source builds are for evaluation; the package version alone does not identify the experimental revision, so record the checkout commit in feedback.
+
+### Define the catalog and candidates
+
+This example uses the React schema. The composer supports catalogs using the standard flat `Spec` format, including named slots. It does not support arbitrary custom spec formats.
+
+```typescript
+// catalog.ts
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/react/schema";
+import { z } from "zod";
+
+export const catalog = defineCatalog(schema, {
+  components: {
+    Panel: { props: z.object({ title: z.string() }), slots: ["default"] },
+    Input: { props: z.object({ label: z.string(), value: z.string() }) },
+    Button: { props: z.object({ label: z.string() }), events: ["press"] },
+  },
+  actions: {
+    savePreferences: { params: z.object({ name: z.string() }) },
+  },
+});
+```
+
+```typescript
+// candidates.ts
+import type { Experimental_CompositionCandidate } from "@json-render/core";
+
+export const candidates = [
+  {
+    id: "preferences",
+    description: "Account preferences panel",
+    element: { type: "Panel", props: { title: "Account preferences" } },
+  },
+  {
+    id: "name",
+    description: "Editable name field",
+    root: false,
+    element: {
+      type: "Input",
+      props: { label: "Name", value: { $bindState: "/name" } },
+    },
+  },
+  {
+    id: "save",
+    description: "Save preferences using the current name",
+    root: false,
+    element: {
+      type: "Button",
+      props: { label: "Save" },
+      on: { press: { action: "savePreferences", params: { name: { $state: "/name" } } } },
+    },
+  },
+] satisfies Experimental_CompositionCandidate[];
+```
+
+### Compose on the server
+
+Set `AI_GATEWAY_API_KEY` in your server environment. Your Gateway team must allow the `typesafe-ai` provider. A separate TypeSafe key is not required. Keep the evaluator and credentials on the server.
+
+```typescript
+// Server only
+import { experimental_composeSpec, experimental_createEvaluator } from "@json-render/core";
+import { catalog } from "./catalog";
+import { candidates } from "./candidates";
+
+const evaluate = experimental_createEvaluator({
+  model: "typesafe-ai/jev",
+  apiKey: process.env.AI_GATEWAY_API_KEY!,
+});
+
+for await (const event of experimental_composeSpec({
+  catalog,
+  candidates,
+  prompt: "Create account preferences with a name field and Save button",
+  initialState: { name: "" },
+  evaluate,
+  maxSteps: 12,
+  maxElements: 24,
+  signal: AbortSignal.timeout(30_000),
+})) {
+  // Send snapshots to your client and render using your existing registry.
+  if (event.type === "step") console.log(event.spec);
+  else console.log(event.stopReason, event.spec);
+}
+```
+
+The adapter uses the plain model ID `typesafe-ai/jev` and Gateway's experimental v4 evaluation endpoint. It has no AI SDK dependency. The default timeout is 10 seconds per evaluation; use `signal` for an overall deadline. See the [core API reference](/docs/api/core#experimental_composespec) for all options.
+
+### Iterate on a version
+
+Pass the selected version as `initialSpec` with the next request:
+
+```typescript
+for await (const event of experimental_composeSpec({
+  catalog,
+  candidates,
+  initialSpec: selectedSpec,
+  prompt: "Remove the Save button",
+  evaluate,
+  signal: AbortSignal.timeout(30_000),
+})) {
+  if (event.spec) updatePreview(event.spec);
+}
+```
+
+Edits can add candidates, replace element recipes, remove non-root subtrees, and move/reorder subtrees. Replacements keep the element's ID, position, and compatible children. Unchanged content, bindings, and state are preserved; the input spec is never mutated. Omit `initialSpec` to start a new composition.
+
+Existing elements use matching candidate descriptions; you can supply `elementDescriptions` keyed by element ID to identify other content. Raw props and state are not shared automatically. Seed specs must be valid trees within the supported catalog and expression subset. Replacement and move operations take two evaluations: select the element, then the recipe or destination. Both count toward the request budget.
+
+### Render and handle actions
+
+Send `step` events over your app's streaming transport and update the preview with `event.spec`. These are full snapshots, not SpecStream patches. Register `Panel`, `Input`, and `Button` in your existing registry, implement `Input` with `useBoundProp`, and bind the `savePreferences` action to your app's handler. See [the React quickstart](/docs/quick-start) and [state binding](/docs/data-binding).
+
+Initialize your renderer's state from `spec.state`. Keep user interaction disabled while composing so incoming snapshots do not compete with edits. Registering an action does not make it safe to execute with arbitrary values: authorize and validate requests in your handler as usual.
+
+On `complete`, inspect `stopReason`: `finish` means composition finished; `unavailable` means the evaluator could not fulfill the request; `limit` means a call, element, or depth budget prevented completion. A complete event can contain a partial spec, or `null` when no root was added. Completion is not a correctness guarantee. Errors and cancellation throw; retain the last snapshot and label it incomplete. Each batched trace is one evaluation (`select` or `layout`), with the individual choices in `step.answers` and usage/timing counted once.
+
+The playground is a reference implementation: [candidates and server wrapper](https://github.com/vercel-labs/json-render/tree/main/apps/web/lib/jev), [streaming route](https://github.com/vercel-labs/json-render/blob/main/apps/web/app/api/generate/route.ts), and [client](https://github.com/vercel-labs/json-render/blob/main/apps/web/components/playground.tsx).
+
+## Validation and v1 limits
+
+- Candidate props and action parameters are validated against their catalog schemas using `initialState`, or `initialSpec.state` when editing without an explicit override. Expressions remain intact in the returned spec. Supply valid initial values; schema defaults and transforms are not applied to recipes.
+- V1 supports literal values, `$state`, `$bindState`, and state-based visibility. Repeats, watches, computed expressions, templates, conditional props, and custom directives are not supported. Candidate recipes remain atomic; use `initialSpec` for an existing tree.
+- Events must be declared by the component. Actions must be in the catalog or the schema's built-in action list. Built-ins without a parameter schema receive name validation only. Success/error callbacks must reference catalog actions.
+- Runtime state can change after composition. The composer cannot validate future values or authorize a later action invocation.
+- The default budget is 32 evaluations, with at most 32 elements in batched creation; default maximum depth is eight. Batching needs at most two evaluations and no separate finish decision. Each candidate is used at most once unless `maxUses` is set. `root: false` excludes it from root selection. A shared `resource` makes candidate variants mutually exclusive.
+- Named slots come from the catalog. Jev selects an existing parent/slot; the composer creates the edge and validates structural integrity before yielding. It does not guarantee an ideal layout or semantic completeness.
+- The evaluator receives the prompt, candidate descriptions, construction instructions, tree topology, and explicit `context`. Initial state, raw props, and binding values are not sent automatically. Put the information needed to choose candidates in their descriptions.
+- Confidence and input usage may be unknown. Confidence is not a calibrated quality threshold. The reusable API does not assume model prices.
+
+## Playground capabilities
+
+To self-host the playground, set `JEV_AI_GATEWAY_API_KEY` on the server for Jev. The default model uses `AI_GATEWAY_API_KEY`; Jev requires its own key and does not fall back to that variable. This is a playground convention: the reusable evaluator accepts whichever server-side key your app passes as `apiKey`.
+
+The playground offers 17 component types with prepared account/contact fields, validation rules, synthetic profile and commerce data, and local Save/Reset/Submit actions. Profile choices include an avatar, display name, role, bio, email, location, and membership badge, bound to the supplied record. A title in double quotes becomes an extra Heading candidate. Values entered in the rendered preview stay in the browser.
+
+Select **jev**, choose **Create account settings**, and send the request. Edit the fields and press **Save changes**. The status changes locally; **Reset** restores the form. Login/contact submission validates inputs and shows a demo toast. The demo does not authenticate users, send messages, or save business records.
+
+Both model options edit the selected version. Try `Design a user profile card`, then `Remove the bio` or `Make the avatar smaller`. After generating settings with Jev, try `Remove the email notifications switch`, `Change the heading to "Account settings"`, or `Move the email field above the name field`. Select any earlier version to branch from it; Clear starts fresh. New text still needs a prepared candidate or a quoted heading. The playground shares existing display labels and matching candidate descriptions to identify edit targets, but does not send entered form values or raw state to Jev. Specs using unsupported expressions cannot be edited by Jev.
+
+For a dashboard, try `Generate a sales dashboard with an orders table at the top, then revenue, orders and new customers metrics in a row, then a weekly revenue chart.` Section order is a model decision, and follow-ups can move the table or chart. Name the sections you need: a vague request such as `Generate a dashboard with the table at the top` can produce only a table. A valid finished spec does not guarantee that the model inferred all the intended content.
+
+The stream tab shows spec patches and decision metadata, and version history labels partial or unavailable results. Requests retain the selected version until edits arrive, including when an edit is unavailable or interrupted.
+
+The playground limits batched creation to 14 elements and runs to 14 evaluations, depth four, and 55 seconds overall, and accepts selected specs with up to 100 elements. Its endpoint uses the web app's minute and daily rate limiters. Self-hosted deployments need `KV_REST_API_URL` and `KV_REST_API_TOKEN` to enable those rate limits.
+
+References: [Jev on Gateway](https://vercel.com/ai-gateway/models/jev), [AI SDK experimental versioning](https://ai-sdk.dev/docs/migration-guides/versioning), [Jev's documented limits](https://docs.typesafe.ai/model-jaggedness/jev-1.13).

apps/web/content/docs/meta.json

@@ -0,0 +1,42 @@
+{
+  "title": "Documentation",
+  "pages": [
+    "---Getting Started---",
+    "index",
+    "installation",
+    "quick-start",
+    "skills",
+    "migration",
+    "changelog",
+    "---Core---",
+    "specs",
+    "schemas",
+    "catalog",
+    "data-binding",
+    "computed-values",
+    "visibility",
+    "watchers",
+    "validation",
+    "directives",
+    "---Rendering---",
+    "renderers",
+    "registry",
+    "streaming",
+    "generation-modes",
+    "---Examples---",
+    "[Browse All Examples](/examples)",
+    "---Guides---",
+    "custom-schema",
+    "code-export",
+    "devtools",
+    "---Experimental---",
+    "jev",
+    "---Integrations---",
+    "ai-sdk",
+    "a2ui",
+    "adaptive-cards",
+    "ag-ui",
+    "openapi",
+    "api"
+  ]
+}

apps/web/content/docs/migration.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/migration")
-
-# Migration Guide
+---
+title: "Migration Guide"
+---
 
 This guide covers breaking changes introduced in v0.6.0 and how to update your code.
 

apps/web/content/docs/openapi.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/openapi")
-
-# OpenAPI Integration
+---
+title: "OpenAPI Integration"
+---
 
 Use json-render to generate dynamic forms and UIs from [OpenAPI/Swagger](https://swagger.io/specification/) schemas.
 

apps/web/content/docs/quick-start.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/quick-start")
-
-# Quick Start
+---
+title: "Quick Start"
+---
 
 Get up and running with json-render in 5 minutes.
 

apps/web/content/docs/registry.mdx

@@ -1,9 +1,8 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/registry")
+---
+title: "Registry"
+---
 
-# Registry
-
-A registry maps your [catalog](/docs/catalog) definitions to platform-specific implementations. The catalog defines *what* AI can generate — the registry provides the *how*.
+A registry maps your [catalog](/docs/catalog) definitions to platform-specific implementations. The catalog defines _what_ AI can generate; the registry provides the _how_.
 
 What a registry contains depends on the schema you use. Each package defines its own schema, which determines the shape of both the catalog and the registry.
 
@@ -19,8 +18,8 @@ What a registry contains depends on the schema you use. Each package defines its
 Use `defineRegistry` to create a type-safe registry from your catalog. Pass your components, actions, or both:
 
 ```tsx
-import { defineRegistry } from '@json-render/react';
-import { myCatalog } from './catalog';
+import { defineRegistry } from "@json-render/react";
+import { myCatalog } from "./catalog";
 
 export const { registry, handlers, executeAction } = defineRegistry(myCatalog, {
   components: {
@@ -33,16 +32,14 @@ export const { registry, handlers, executeAction } = defineRegistry(myCatalog, {
     ),
 
     Button: ({ props, emit }) => (
-      <button onClick={() => emit("press")}>
-        {props.label}
-      </button>
+      <button onClick={() => emit("press")}>{props.label}</button>
     ),
   },
 
   actions: {
     submit_form: async (params, setState) => {
-      const res = await fetch('/api/submit', {
-        method: 'POST',
+      const res = await fetch("/api/submit", {
+        method: "POST",
         body: JSON.stringify(params),
       });
       const result = await res.json();
@@ -69,23 +66,36 @@ Each component receives a `ComponentContext` object:
 
 ```typescript
 interface ComponentContext {
-  props: T;                                // Type-safe props from your catalog
-  children?: React.ReactNode;              // Rendered children (for slot components)
-  emit: (event: string) => void;           // Emit a named event (always defined)
-  on: (event: string) => EventHandle;      // Get event handle with metadata
-  loading?: boolean;                       // Whether the renderer is in a loading state
-  bindings?: Record<string, string>;       // State paths from $bindState/$bindItem expressions
+  props: T; // Type-safe props from your catalog
+  children?: React.ReactNode; // Rendered children (for slot components)
+  slots?: Record<string, React.ReactNode>; // Rendered named slots
+  emit: (event: string) => void; // Emit a named event (always defined)
+  on: (event: string) => EventHandle; // Get event handle with metadata
+  loading?: boolean; // Whether the renderer is in a loading state
+  bindings?: Record<string, string>; // State paths from $bindState/$bindItem expressions
 }
 
 interface EventHandle {
-  emit: () => void;              // Fire the event
+  emit: () => void; // Fire the event
   shouldPreventDefault: boolean; // Whether any binding requested preventDefault
-  bound: boolean;                // Whether any handler is bound
+  bound: boolean; // Whether any handler is bound
 }
 ```
 
 Props are automatically inferred from your catalog, so `props.title` is typed as `string` if your catalog defines it that way.
 
+For components with named slots, read the default content from `children` and other regions from `slots`:
+
+```tsx
+Layout: ({ children, slots }) => (
+  <div>
+    <header>{slots?.header}</header>
+    <main>{children}</main>
+    <footer>{slots?.footer}</footer>
+  </div>
+),
+```
+
 Use `emit("press")` for simple event firing. Use `on("click")` when you need to inspect event metadata:
 
 ```tsx
@@ -128,27 +138,29 @@ TextInput: ({ props, bindings }) => {
 
 ### Action Handlers
 
-Instead of AI generating arbitrary code, it declares *intent* by name. Your application provides the implementation. This is a core guardrail.
+Instead of AI generating arbitrary code, it declares _intent_ by name. Your application provides the implementation. This is a core guardrail.
 
 Actions are declared in your [catalog](/docs/catalog). The `@json-render/react` schema supports an `actions` key where you define what operations AI can trigger:
 
 ```typescript
-import { defineCatalog } from '@json-render/core';
-import { schema } from '@json-render/react/schema';
-import { z } from 'zod';
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/react/schema";
+import { z } from "zod";
 
 const catalog = defineCatalog(schema, {
-  components: { /* ... */ },
+  components: {
+    /* ... */
+  },
   actions: {
     submit_form: {
       params: z.object({
         formId: z.string(),
       }),
-      description: 'Submit a form',
+      description: "Submit a form",
     },
     export_data: {
       params: z.object({
-        format: z.enum(['csv', 'pdf', 'json']),
+        format: z.enum(["csv", "pdf", "json"]),
       }),
     },
     navigate: {
@@ -166,8 +178,8 @@ Action handlers receive `(params, setState, state)` and are defined inside `defi
 export const { handlers, executeAction } = defineRegistry(catalog, {
   actions: {
     submit_form: async (params, setState) => {
-      const response = await fetch('/api/submit', {
-        method: 'POST',
+      const response = await fetch("/api/submit", {
+        method: "POST",
         body: JSON.stringify({ formId: params.formId }),
       });
       const result = await response.json();
@@ -219,14 +231,14 @@ For read-only state access (e.g. displaying a value from state), use `$state` ex
 Wire everything together with providers and the `<Renderer />` component:
 
 ```tsx
-import { useMemo, useRef } from 'react';
+import { useMemo, useRef } from "react";
 import {
   Renderer,
   StateProvider,
   VisibilityProvider,
   ActionProvider,
-} from '@json-render/react';
-import { registry, handlers } from './registry';
+} from "@json-render/react";
+import { registry, handlers } from "./registry";
 
 function App({ spec, state, setState }) {
   const stateRef = useRef(state);
@@ -235,7 +247,11 @@ function App({ spec, state, setState }) {
   setStateRef.current = setState;
 
   const actionHandlers = useMemo(
-    () => handlers(() => setStateRef.current, () => stateRef.current),
+    () =>
+      handlers(
+        () => setStateRef.current,
+        () => stateRef.current,
+      ),
     [],
   );
 
@@ -256,8 +272,8 @@ function App({ spec, state, setState }) {
 `@json-render/react-native` uses the same `defineRegistry` API. The only difference is that components return React Native elements instead of HTML:
 
 ```tsx
-import { defineRegistry } from '@json-render/react-native';
-import { View, Text, Pressable } from 'react-native';
+import { defineRegistry } from "@json-render/react-native";
+import { View, Text, Pressable } from "react-native";
 
 export const { registry } = defineRegistry(catalog, {
   components: {
@@ -284,14 +300,14 @@ See the [@json-render/react-native API reference](/docs/api/react-native) for th
 `@json-render/react-email` uses `defineRegistry` like React and React Native. Components render to React Email primitives (`@react-email/components`). Use `renderToHtml` or `renderToPlainText` for server-side email output:
 
 ```tsx
-import { defineRegistry } from '@json-render/react-email';
-import { renderToHtml } from '@json-render/react-email';
-import { Body, Container, Heading, Text } from '@react-email/components';
+import { defineRegistry } from "@json-render/react-email";
+import { renderToHtml } from "@json-render/react-email";
+import { Body, Container, Heading, Text } from "@react-email/components";
 
 export const { registry } = defineRegistry(catalog, {
   components: {
     Card: ({ props, children }) => (
-      <Container style={{ padding: 16, backgroundColor: '#fff' }}>
+      <Container style={{ padding: 16, backgroundColor: "#fff" }}>
         <Heading>{props.title}</Heading>
         {children}
       </Container>
@@ -309,10 +325,10 @@ See the [@json-render/react-email API reference](/docs/api/react-email) for the
 `@json-render/remotion` takes a different approach. Instead of `defineRegistry`, it uses a plain component registry with built-in standard components for video production:
 
 ```tsx
-import { Renderer, standardComponents } from '@json-render/remotion';
+import { Renderer, standardComponents } from "@json-render/remotion";
 
 // Use the standard components directly
-<Renderer spec={timelineSpec} components={standardComponents} />
+<Renderer spec={timelineSpec} components={standardComponents} />;
 
 // Or extend with your own
 const components = {

apps/web/content/docs/renderers.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata";
-export const metadata = pageMetadata("docs/renderers");
-
-# Renderers
+---
+title: "Renderers"
+---
 
 json-render supports multiple output targets. Each renderer takes the same core concept -- a JSON spec constrained to a catalog -- and renders it natively on a different platform or into a different format.
 
@@ -62,6 +61,15 @@ All renderers share the same workflow:
       </td>
       <td>Native mobile views</td>
     </tr>
+    <tr>
+      <td>TanStack Start</td>
+      <td>
+        <code>@json-render/tanstack-start</code>
+      </td>
+      <td>
+        Full React applications with routes, layouts, SSR, and head metadata
+      </td>
+    </tr>
     <tr>
       <td>Image</td>
       <td>
@@ -213,6 +221,32 @@ const { registry } = defineRegistry(catalog, { components: {} });
 
 See the [@json-render/react-native API reference](/docs/api/react-native) for details.
 
+## TanStack Start
+
+Define complete TanStack Start applications with route specs, reusable layouts,
+loader-backed state, head metadata, and prerender paths. The integration uses
+the React renderer for each page and TanStack Router for navigation.
+
+```tsx
+import { createFileRoute, notFound } from "@tanstack/react-router";
+import { PageRenderer } from "@json-render/tanstack-start";
+import { createStartApp } from "@json-render/tanstack-start/server";
+
+const { getPageData, getHead } = createStartApp({ spec });
+
+export const Route = createFileRoute("/$")({
+  loader: async ({ location }) => {
+    const data = await getPageData({ pathname: location.pathname });
+    if (!data) throw notFound();
+    return data;
+  },
+  head: ({ match }) => getHead({ pathname: match.pathname }),
+  component: () => <PageRenderer {...Route.useLoaderData()} />,
+});
+```
+
+See the [@json-render/tanstack-start API reference](/docs/api/tanstack-start) for details.
+
 ## Image
 
 Generate SVG and PNG images from JSON specs using Satori. Ideal for OG images, social cards, and banners.

apps/web/content/docs/schemas.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/schemas")
-
-# Schemas
+---
+title: "Schemas"
+---
 
 Schemas define the structure and validation rules for your UI specs.
 

apps/web/content/docs/skills.mdx

@@ -1,8 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata";
-
-export const metadata = pageMetadata("docs/skills");
-
-# Skills
+---
+title: "Skills"
+---
 
 json-render ships with skills that teach AI coding agents how to use each package. Install a skill and your agent in Cursor, Claude Code, or Codex can generate json-render UIs without manual guidance.
 
@@ -10,6 +8,12 @@ json-render ships with skills that teach AI coding agents how to use each packag
 
 - **core** — Core schemas, catalogs, and AI prompt generation.
 - **react** — React renderer that turns JSON specs into React component trees.
+- **tanstack-start** — Full TanStack Start applications with routes, layouts, SSR loaders, and head metadata.
+- **devtools** — Framework-agnostic inspector panel for specs, state, actions, streams, catalogs, and DOM picking.
+- **devtools-react** — React adapter for the json-render devtools panel.
+- **devtools-vue** — Vue adapter for the json-render devtools panel.
+- **devtools-svelte** — Svelte adapter for the json-render devtools panel.
+- **devtools-solid** — SolidJS adapter for the json-render devtools panel.
 - **react-pdf** — PDF renderer using `@react-pdf/renderer`.
 - **react-email** — Email renderer that produces HTML or plain-text emails.
 - **react-native** — React Native renderer for native mobile UIs.
@@ -31,6 +35,12 @@ json-render ships with skills that teach AI coding agents how to use each packag
 ```bash
 npx skills add vercel-labs/json-render --skill core
 npx skills add vercel-labs/json-render --skill react
+npx skills add vercel-labs/json-render --skill tanstack-start
+npx skills add vercel-labs/json-render --skill devtools
+npx skills add vercel-labs/json-render --skill devtools-react
+npx skills add vercel-labs/json-render --skill devtools-vue
+npx skills add vercel-labs/json-render --skill devtools-svelte
+npx skills add vercel-labs/json-render --skill devtools-solid
 npx skills add vercel-labs/json-render --skill react-pdf
 npx skills add vercel-labs/json-render --skill react-email
 npx skills add vercel-labs/json-render --skill react-native
@@ -58,6 +68,30 @@ The foundational skill. Teaches agents how to define catalogs, create schemas, b
 
 Teaches agents how to render JSON specs as React component trees using `JsonRender`, `JsonRenderClient`, and `useJsonRender`. Covers custom component registries, client-side interactivity, state management, and streaming integration.
 
+## tanstack-start
+
+Teaches agents how to build JSON-defined TanStack Start applications with splat routes, reusable layouts, SSR-safe loaders, head metadata, prerender paths, and client navigation.
+
+## devtools
+
+Teaches agents how to add and configure the framework-agnostic json-render devtools panel, including spec inspection, state editing, action and stream timelines, catalog browsing, and DOM picking.
+
+## devtools-react
+
+Teaches agents how to mount and control `@json-render/devtools-react` inside a React json-render provider, including the imperative devtools hook.
+
+## devtools-vue
+
+Teaches agents how to mount and configure `@json-render/devtools-vue` inside a Vue json-render provider.
+
+## devtools-svelte
+
+Teaches agents how to mount and configure `@json-render/devtools-svelte` inside a Svelte 5 json-render provider.
+
+## devtools-solid
+
+Teaches agents how to mount and configure `@json-render/devtools-solid` inside a SolidJS json-render provider.
+
 ## react-pdf
 
 Teaches agents how to generate PDFs from JSON specs using `@react-pdf/renderer`. Covers the PDF-specific component registry, page layout, and styling.

apps/web/content/docs/specs.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/specs")
-
-# Specs
+---
+title: "Specs"
+---
 
 A spec is a JSON document that describes your UI.
 
@@ -60,7 +59,10 @@ A more complex spec with multiple nested elements:
     },
     "avatar-1": {
       "type": "Avatar",
-      "props": { "src": { "$state": "/user/avatar" }, "alt": { "$state": "/user/name" } },
+      "props": {
+        "src": { "$state": "/user/avatar" },
+        "alt": { "$state": "/user/name" }
+      },
       "children": []
     },
     "stack-1": {
@@ -102,7 +104,10 @@ A high-level spec using semantic blocks for page layouts:
     },
     "header": {
       "type": "Header",
-      "props": { "logo": "/logo.svg", "navItems": ["Products", "Pricing", "Docs"] },
+      "props": {
+        "logo": "/logo.svg",
+        "navItems": ["Products", "Pricing", "Docs"]
+      },
       "children": []
     },
     "hero": {
@@ -122,22 +127,37 @@ A high-level spec using semantic blocks for page layouts:
     },
     "feature-1": {
       "type": "Feature",
-      "props": { "icon": "zap", "title": "Fast", "description": "Render UIs in milliseconds" },
+      "props": {
+        "icon": "zap",
+        "title": "Fast",
+        "description": "Render UIs in milliseconds"
+      },
       "children": []
     },
     "feature-2": {
       "type": "Feature",
-      "props": { "icon": "shield", "title": "Secure", "description": "Validate all specs against your catalog" },
+      "props": {
+        "icon": "shield",
+        "title": "Secure",
+        "description": "Validate all specs against your catalog"
+      },
       "children": []
     },
     "feature-3": {
       "type": "Feature",
-      "props": { "icon": "sparkles", "title": "AI-Ready", "description": "Generate prompts from your catalog" },
+      "props": {
+        "icon": "sparkles",
+        "title": "AI-Ready",
+        "description": "Generate prompts from your catalog"
+      },
       "children": []
     },
     "footer": {
       "type": "Footer",
-      "props": { "copyright": "2025 Acme Inc", "links": ["Privacy", "Terms", "Contact"] },
+      "props": {
+        "copyright": "2025 Acme Inc",
+        "links": ["Privacy", "Terms", "Contact"]
+      },
       "children": []
     }
   }
@@ -174,13 +194,18 @@ Each element in the map has a consistent shape:
 {
   "type": "ComponentName",
   "props": { "label": "Hello" },
-  "children": ["child-1", "child-2"]
+  "children": ["child-1", "child-2"],
+  "slots": {
+    "header": ["heading-1"],
+    "footer": ["actions-1"]
+  }
 }
 ```
 
 - `type` — Component type from your catalog
 - `props` — Component properties
 - `children` — Array of child element keys
+- `slots`: Optional map of named slots to child element keys. Use `children` for the default slot. Named slot rendering is supported by `@json-render/react` and `@json-render/vue`.
 
 ### Dynamic Data
 
@@ -225,12 +250,12 @@ Control when elements appear using the `visible` property:
 Use `validateSpec` from `@json-render/core` to check a spec for structural issues:
 
 ```typescript
-import { validateSpec } from '@json-render/core';
+import { validateSpec } from "@json-render/core";
 
 const result = validateSpec(spec);
 
 if (!result.valid) {
-  console.error('Invalid spec:', result.issues);
+  console.error("Invalid spec:", result.issues);
 }
 ```
 
@@ -239,8 +264,12 @@ if (!result.valid) {
 With `@json-render/react`, wrap the `Renderer` in providers to supply state and visibility:
 
 ```tsx
-import { Renderer, StateProvider, VisibilityProvider } from '@json-render/react';
-import { registry } from './registry';
+import {
+  Renderer,
+  StateProvider,
+  VisibilityProvider,
+} from "@json-render/react";
+import { registry } from "./registry";
 
 function MyApp({ spec, initialState }) {
   return (
@@ -260,20 +289,14 @@ See the [@json-render/react API reference](/docs/api/react) for full provider an
 With `@json-render/react`, use the `useUIStream` hook to stream specs incrementally:
 
 ```tsx
-import { useUIStream } from '@json-render/react';
+import { useUIStream } from "@json-render/react";
 
 function GenerativeUI() {
   const { spec, isStreaming } = useUIStream({
-    api: '/api/generate',
+    api: "/api/generate",
   });
 
-  return (
-    <Renderer
-      spec={spec}
-      registry={registry}
-      loading={isStreaming}
-    />
-  );
+  return <Renderer spec={spec} registry={registry} loading={isStreaming} />;
 }
 ```
 

apps/web/content/docs/streaming.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/streaming")
-
-# Streaming
+---
+title: "Streaming"
+---
 
 Progressively render UI as AI generates it.
 

apps/web/content/docs/validation.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/validation")
-
-# Validation
+---
+title: "Validation"
+---
 
 Validate form inputs with built-in and custom functions.
 

apps/web/content/docs/visibility.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/visibility")
-
-# Visibility
+---
+title: "Visibility"
+---
 
 Conditionally show or hide components based on state values and logic.
 
@@ -199,6 +198,24 @@ With comparison:
 
 This shows the divider for every item except the first (index 0).
 
+### Filtered lists — `$item` on the repeat container
+
+Putting an `$item` condition directly on the element that declares `repeat` filters which items render. This is the natural way to build kanban columns, tabbed lists, or status sections from one state array:
+
+```json
+{
+  "type": "Stack",
+  "repeat": { "statePath": "/tasks", "key": "id" },
+  "visible": { "$item": "status", "eq": "todo" },
+  "children": ["task-card"]
+}
+```
+
+One child renders per matching item; non-matching items are skipped. When the condition is an `$and` (or array) that mixes scopes, the `$state` parts gate the container itself (a false gate hides the whole shell) while the `$item`/`$index` parts filter items. A mixed `$or` cannot be split and is applied entirely per item.
+
+Filtered lists are currently implemented by the React renderer; other renderers evaluate the container condition outside the repeat scope.
+
+
 `$item` and `$index` conditions support the same comparison operators as `$state` (`eq`, `neq`, `gt`, `gte`, `lt`, `lte`, `not`).
 
 ## Complex Example

apps/web/content/docs/watchers.mdx

@@ -1,7 +1,6 @@
-import { pageMetadata } from "@/lib/page-metadata"
-export const metadata = pageMetadata("docs/watchers")
-
-# Watchers
+---
+title: "Watchers"
+---
 
 React to state changes by triggering actions when watched paths update.
 

apps/web/eslint.config.js

@@ -2,6 +2,7 @@ import { nextJsConfig } from "@internal/eslint-config/next-js";
 
 /** @type {import("eslint").Linter.Config[]} */
 export default [
+  { ignores: [".source/**"] },
   ...nextJsConfig,
   {
     rules: {

apps/web/lib/docs-navigation.ts

@@ -32,6 +32,7 @@ export const docsNavigation: NavSection[] = [
       { title: "Visibility", href: "/docs/visibility" },
       { title: "Watchers", href: "/docs/watchers" },
       { title: "Validation", href: "/docs/validation" },
+      { title: "Directives", href: "/docs/directives" },
     ],
   },
   {
@@ -52,12 +53,14 @@ export const docsNavigation: NavSection[] = [
     items: [
       { title: "Custom Schema", href: "/docs/custom-schema" },
       { title: "Code Export", href: "/docs/code-export" },
+      { title: "Devtools", href: "/docs/devtools" },
     ],
   },
   {
     title: "Integrations",
     items: [
       { title: "AI SDK", href: "/docs/ai-sdk" },
+      { title: "Jev (Experimental)", href: "/docs/jev" },
       { title: "A2UI", href: "/docs/a2ui" },
       { title: "Adaptive Cards", href: "/docs/adaptive-cards" },
       { title: "AG-UI", href: "/docs/ag-ui" },
@@ -70,6 +73,10 @@ export const docsNavigation: NavSection[] = [
       { title: "@json-render/core", href: "/docs/api/core" },
       { title: "@json-render/react", href: "/docs/api/react" },
       { title: "@json-render/next", href: "/docs/api/next" },
+      {
+        title: "@json-render/tanstack-start",
+        href: "/docs/api/tanstack-start",
+      },
       { title: "@json-render/react-pdf", href: "/docs/api/react-pdf" },
       { title: "@json-render/react-email", href: "/docs/api/react-email" },
       { title: "@json-render/shadcn", href: "/docs/api/shadcn" },
@@ -85,7 +92,22 @@ export const docsNavigation: NavSection[] = [
         title: "@json-render/react-three-fiber",
         href: "/docs/api/react-three-fiber",
       },
+      { title: "@json-render/directives", href: "/docs/api/directives" },
       { title: "@json-render/codegen", href: "/docs/api/codegen" },
+      { title: "@json-render/devtools", href: "/docs/api/devtools" },
+      {
+        title: "@json-render/devtools-react",
+        href: "/docs/api/devtools-react",
+      },
+      { title: "@json-render/devtools-vue", href: "/docs/api/devtools-vue" },
+      {
+        title: "@json-render/devtools-svelte",
+        href: "/docs/api/devtools-svelte",
+      },
+      {
+        title: "@json-render/devtools-solid",
+        href: "/docs/api/devtools-solid",
+      },
       { title: "@json-render/mcp", href: "/docs/api/mcp" },
       { title: "@json-render/redux", href: "/docs/api/redux" },
       { title: "@json-render/zustand", href: "/docs/api/zustand" },

apps/web/lib/docs-response-headers.ts

@@ -0,0 +1,26 @@
+const negotiationHeaders = [
+  "Accept",
+  "User-Agent",
+  "Signature-Agent",
+  "Sec-Fetch-Mode",
+  "Sec-Fetch-Dest",
+  "RSC",
+  "Next-Router-Prefetch",
+  "Next-Router-Segment-Prefetch",
+  "Purpose",
+  "Sec-Purpose",
+];
+
+export function applyDocsResponseHeaders(headers: Headers) {
+  const tokens = new Map<string, string>();
+  for (const token of [
+    ...(headers.get("Vary") ?? "").split(/\s*,\s*/),
+    ...negotiationHeaders,
+  ]) {
+    if (token) tokens.set(token.toLowerCase(), token);
+  }
+  headers.set("Vary", [...tokens.values()].join(", "));
+  headers.set("Cache-Control", "private, no-store");
+  headers.set("CDN-Cache-Control", "no-store");
+  headers.set("Vercel-CDN-Cache-Control", "no-store");
+}

apps/web/lib/docs-source.ts

@@ -0,0 +1,69 @@
+import { readFile } from "node:fs/promises";
+import { join } from "node:path";
+import { parse } from "yaml";
+import { allDocsPages } from "./docs-navigation";
+import { mdxToCleanMarkdown } from "./mdx-to-markdown";
+import { siteUrl } from "./site";
+
+export const docsPages = allDocsPages.filter(
+  (page) => page.href === "/docs" || page.href.startsWith("/docs/"),
+);
+const inventory = new Map(docsPages.map((page) => [page.href, page]));
+const pending = new Map<string, Promise<DocsSource>>();
+
+export type DocsSource = {
+  href: string;
+  title: string;
+  markdown: string;
+  markdownUrl: string;
+  canonicalUrl: string;
+};
+
+export function isSafePathSegments(segments: readonly string[]) {
+  return segments.every(
+    (part) =>
+      part.length > 0 &&
+      part !== "." &&
+      part !== ".." &&
+      !part.includes("/") &&
+      !part.includes("\\"),
+  );
+}
+
+export function loadDocsSource(pathname: string): Promise<DocsSource> | null {
+  const href = pathname.endsWith("/") ? pathname.slice(0, -1) : pathname;
+  if (!inventory.has(href)) return null;
+  let result = pending.get(href);
+  if (!result) {
+    const slug = href === "/docs" ? "index" : href.slice("/docs/".length);
+    result = readFile(
+      join(process.cwd(), "content", "docs", `${slug}.mdx`),
+      "utf8",
+    ).then((raw) => {
+      const frontmatter = raw.match(/^---\r?\n([\s\S]*?)\r?\n---\r?\n/);
+      if (!frontmatter) throw new Error(`Missing frontmatter for ${href}`);
+      const metadata = parse(frontmatter[1] ?? "") as {
+        title?: unknown;
+      } | null;
+      if (typeof metadata?.title !== "string")
+        throw new Error(`Missing title for ${href}`);
+      const title = metadata.title;
+      return {
+        href,
+        title,
+        markdown: mdxToCleanMarkdown(
+          `# ${title}\n${raw.slice(frontmatter[0].length)}`,
+        ),
+        markdownUrl: `${href}.md`,
+        canonicalUrl: `${siteUrl}${href}`,
+      };
+    });
+    pending.set(href, result);
+    result.catch(() => pending.delete(href));
+  }
+  return result;
+}
+
+export async function loadAllDocsSources() {
+  return Promise.all(docsPages.map((page) => loadDocsSource(page.href)!));
+}

apps/web/lib/examples.ts

@@ -108,6 +108,22 @@ export const examples: Example[] = [
     githubPath: "examples/react-three-fiber",
     demoUrl: "https://react-three-fiber-demo.json-render.dev",
   },
+  {
+    slug: "gsplat",
+    title: "Gaussian Splatting (experimental)",
+    description:
+      "Experimental standalone gaussian splat viewer using gsplat.js — no Three.js dependency.",
+    tags: ["React", "3D", "Next.js"],
+    githubPath: "examples/gsplat",
+  },
+  {
+    slug: "react-three-fiber-gsplat",
+    title: "R3F + Gaussian Splatting",
+    description:
+      "Gaussian splats composed with 3D primitives and lights in React Three Fiber scenes.",
+    tags: ["React", "3D", "Next.js"],
+    githubPath: "examples/react-three-fiber-gsplat",
+  },
   {
     slug: "react-native",
     title: "React Native",

apps/web/lib/geistdocs/config.tsx

@@ -0,0 +1,30 @@
+import { defineConfig } from "@vercel/geistdocs/config";
+import { siteUrl } from "@/lib/site";
+
+export const config = defineConfig({
+  title: "json-render",
+  siteUrl,
+  defaultLanguage: "en",
+  logo: <span className="font-medium">json-render</span>,
+  navbarActiveProduct: "json-render",
+  navbarBrand: "labs",
+  github: {
+    owner: "vercel-labs",
+    repo: "json-render",
+    branch: "main",
+    editPath: "apps/web/content/docs",
+  },
+  content: [
+    { id: "docs", label: "Documentation", dir: "content/docs", route: "/docs" },
+  ],
+  nav: [
+    { label: "Docs", href: "/docs" },
+    { label: "Playground", href: "/playground" },
+    { label: "Examples", href: "/examples" },
+  ],
+  ai: { enabled: false },
+  feedback: { enabled: false },
+  language: { enabled: false },
+  pageActions: { askAI: false, openInChat: false },
+  webmcp: { enabled: true },
+});