> **🏗️ build-from-issue-agent**
Closes#79
## Summary
Replaces the gateway-proxied inference model (`ProxyInference` RPC) with sandbox-local execution. The sandbox now resolves routes from either a standalone YAML route file or a cluster bundle fetched via the new `GetSandboxInferenceBundle` RPC, then forwards requests directly to inference backends using `navigator-router`.
### Benefits of removing the gRPC hop
Moving inference execution from the gateway to the sandbox eliminates the gRPC round-trip for every inference request:
- **No payload size limits**: Direct HTTP forwarding replaces protobuf-over-gRPC serialization.
- **Streaming-ready**: Preserves connection semantics for future SSE support (e.g., `stream: true`).
- **Lower latency**: Direct sandbox → backend path instead of sandbox → gateway → backend round-trip.
- **Reduced gateway load**: Gateway only serves the control-plane bundle delivery RPC.
- **Simpler error model**: HTTP status codes flow through directly without gRPC wrapping.
## Changes Made
- **Proto**: Removed `ProxyInference` RPC. Added `GetSandboxInferenceBundle` RPC for route bundle delivery.
- **Gateway**: Replaced `proxy_inference` with `get_sandbox_inference_bundle`. Removed `Router` and `navigator-router` dependency — gateway is now control-plane only for inference.
- **Router**: Switched config file format from TOML to YAML. Added `Debug` impl that redacts API keys.
- **Sandbox**: New `InferenceContext` with local `Router` + route cache. Routes loaded from `--inference-routes` file (standalone) or cluster bundle via gRPC, with 30s background refresh. New `--inference-routes` / `NAVIGATOR_INFERENCE_ROUTES` CLI arg.
- **Dev sandbox**: Added `inference-routes.yaml` at repo root with default NVIDIA NIM route. `mise run sandbox` now mounts it automatically and supports `-e` flag to forward env vars (e.g., `mise run sandbox`).
- **Example**: Added standalone example (`examples/inference/routes.yaml`) and rewrote README to cover both standalone and cluster workflows.
- **E2E tests**: Updated existing test names/docs. Added tests for Anthropic messages protocol and multi-route policy filtering.
## Tests Added
- **Unit (21 new):** `router_error_to_http` (6 variants), `load_from_file` YAML round-trip (5), `resolve_sandbox_inference_bundle` gRPC handler (6), `build_inference_context` route loading (4)
- **E2E (2 new):** Anthropic messages protocol routing, route filtering by `allowed_routes`
- **Total:** 188 unit tests passing across 3 crates
## Documentation Updated
- `architecture/gateway.md`: Removed router, updated Inference Service
- `architecture/sandbox.md`: Updated orchestration flow, InferenceContext, route loading
- `architecture/inference-routing.md`: Complete rewrite for sandbox-local architecture
## Verification
- [x] All unit tests passing (188 across 3 crates)
- [x] Pre-commit Rust checks passing (fmt, clippy, tests)
- [x] Architecture documentation updated
- [x] E2E tests updated with new test cases
- [x] Standalone example and documentation added
- [x] Default inference-routes.yaml with env passthrough for mise run sandbox
Closes#67
## Summary
Implements transparent inference interception and routing for sandboxed AI agents. The sandbox proxy intercepts outbound AI SDK calls (OpenAI, Anthropic) and reroutes them through the gateway to policy-controlled backends — enabling organizations to redirect inference traffic to local or self-hosted models without modifying agent code.
**Decision model** — a tri-state OPA evaluation for every CONNECT request:
1. Binary + endpoint explicitly allowed in `network_policies` → **allow** (pass through)
2. Not explicitly allowed + `inference.allowed_routes` configured → **inspect for inference** (TLS intercept, detect API patterns, route through gateway)
3. Otherwise → **deny**
No endpoint declarations or binary lists needed for inference routing. Just configure `inference.allowed_routes`.
## Key Changes
### Sandbox (interception)
- **OPA policy**: New `network_action` Rego rule with three outcomes (`allow`, `inspect_for_inference`, `deny`). New `NetworkAction` enum replaces `PolicyDecision.allowed` bool for the proxy's main decision path.
- **Proxy**: New `InspectForInference` path — TLS-terminates client, parses HTTP, detects inference API patterns (`POST /v1/chat/completions`, `/v1/completions`, `/v1/messages`), strips auth headers, forwards via gRPC.
- **New module**: `l7/inference.rs` — `InferenceApiPattern`, `detect_inference_pattern()`, HTTP request/response parsing.
- **gRPC client**: New `proxy_inference()` for sandbox→gateway forwarding.
- **Sandbox init**: Creates OPA engine when inference is configured, even without `network_policies`.
### Gateway (dispatch)
- **InferenceService**: `ProxyInference` RPC loads sandbox policy, resolves allowed routes, dispatches to router. Full CRUD for inference routes.
- **Proto**: `InferenceRoute`, `InferenceRouteSpec`, `ProxyInferenceRequest/Response`, Inference gRPC service.
### Router (backend proxying)
- **New crate**: `navigator-router` with `Router`, `proxy_with_candidates()`, protocol-based route selection, backend HTTP proxying with auth header rewriting.
- **Mock support** for testing (`mock://` scheme).
### CLI
- `nav inference create/update/delete/list` commands for route management.
### Python SDK
- Updated protobuf bindings. Removed old `inference.py` client (replaced by transparent interception).
### Documentation
- New `architecture/inference-routing.md` — end-to-end system documentation.
- Updated `architecture/sandbox.md` — proxy, OPA, and source index sections.
- Updated `architecture/README.md` — new subsystem overview and diagram.
## Addendum: Chunked Transfer Compatibility
This branch now also fixes intercepted SDK requests that send chunked request bodies:
- `inspect_for_inference` now accepts `Transfer-Encoding: chunked` and decodes chunked request bodies before forwarding to the gateway
- Removed the prior `411 Length Required` response for chunked intercepted requests
- Added request/response header sanitization for framing and hop-by-hop headers (`content-length`, `transfer-encoding`, `connection`, etc.) to keep forwarded requests and returned responses valid
- Added unit tests for chunked parsing and header sanitization
Note: this improves compatibility for streaming-style SDK request patterns; true token-by-token passthrough response streaming is still a separate follow-up.
## Minimal Policy for Inference Routing
```yaml
inference:
allowed_routes:
- local
```
Any outgoing connection from a binary not explicitly allowed in `network_policies` will be intercepted and checked for inference API patterns.
## Test Plan
- [x] `cargo test --workspace` — all tests pass
- [x] `mise run pre-commit` — all checks pass
- [x] E2E: OpenAI chat completions routed through gateway
- [x] E2E: Anthropic messages routed through gateway
- [x] E2E: Python OpenAI SDK from sandbox (`examples/inference/inference.py`)
- [x] E2E test: `e2e/python/test_inference_routing.py`
Closes#13
## Summary
- add Python sandbox execution APIs for command and callable workflows
- consolidate sandbox policy fixtures and expand e2e test coverage for policy and Python exec paths
- update CI/build config and images for sandbox e2e execution dependencies
## Test Plan
- mise run pre-commit
Drew Newberry