feat(opencode): add JSONC config support without external dependency (#205)

OpenCode supports opencode.jsonc as config format. Added .jsonc paths
to config detection and a 3-line stripJsonComments function instead of
the jsonc-parser dependency (208KB). Priority: .json before .jsonc at
each level. writeSettings writes back to the same file it read.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/adapters/opencode/index.ts

@@ -17,6 +17,14 @@
  */
 
 import { createHash } from "node:crypto";
+
+/** Strip JSONC comments (// and /* *​/) and trailing commas for JSON.parse. */
+function stripJsonComments(str: string): string {
+  return str
+    .replace(/\/\/.*$/gm, "")
+    .replace(/\/\*[\s\S]*?\*\//g, "")
+    .replace(/,(\s*[}\]])/g, "$1");
+}
 import {
   readFileSync,
   writeFileSync,
@@ -230,8 +238,11 @@ export class OpenCodeAdapter implements HookAdapter {
     }
     return [
       resolve("opencode.json"),
+      resolve("opencode.jsonc"),
       resolve(".opencode", "opencode.json"),
+      resolve(".opencode", "opencode.jsonc"),
       join(homedir(), ".config", "opencode", "opencode.json"),
+      join(homedir(), ".config", "opencode", "opencode.jsonc"),
     ];
   }
 
@@ -307,7 +318,8 @@ export class OpenCodeAdapter implements HookAdapter {
       try {
         const raw = readFileSync(configPath, "utf-8");
         this.settingsPath = configPath;
-        return JSON.parse(raw) as Record<string, unknown>;
+        const text = configPath.endsWith(".jsonc") ? stripJsonComments(raw) : raw;
+        return JSON.parse(text) as Record<string, unknown>;
       } catch {
         continue;
       }
@@ -334,7 +346,7 @@ export class OpenCodeAdapter implements HookAdapter {
       results.push({
         check: "Plugin configuration",
         status: "fail",
-        message: "Could not read opencode.json",
+        message: `Could not read ${this.platform}.json or ${this.platform}.jsonc`,
         fix: "context-mode upgrade",
       });
       return results;
@@ -380,7 +392,7 @@ export class OpenCodeAdapter implements HookAdapter {
       return {
         check: "Plugin registration",
         status: "warn",
-        message: "Could not read opencode.json",
+        message: `Could not read ${this.platform}.json or ${this.platform}.jsonc`,
       };
     }
 

tests/adapters/opencode.test.ts

@@ -257,6 +257,113 @@ describe("OpenCodeAdapter", () => {
       rmSync(root, { recursive: true, force: true });
     });
 
+    it("readSettings reads opencode.jsonc with comments stripped", () => {
+      const root = mkdtempSync(join(tmpdir(), "opencode-adapter-"));
+      const dir = join(root, "project");
+      const src = resolve(process.cwd(), "src", "adapters", "opencode", "index.ts");
+      const tsx = resolve(process.cwd(), "node_modules", "tsx", "dist", "cli.mjs");
+      mkdirSync(dir, { recursive: true });
+      writeFileSync(
+        join(dir, "opencode.jsonc"),
+        `{
+  // This is a line comment
+  "plugin": ["context-mode"],
+  /* Block comment */
+  "version": "1.0"
+}
+`,
+      );
+      const run = spawnSync(
+        process.execPath,
+        [
+          tsx,
+          "-e",
+          `import { OpenCodeAdapter } from ${JSON.stringify(src)};const a=new OpenCodeAdapter();console.log(JSON.stringify(a.readSettings()))`,
+        ],
+        { cwd: dir, env: env(join(root, "home")), encoding: "utf-8" },
+      );
+      expect(run.status).toBe(0);
+      expect(JSON.parse(run.stdout)).toEqual({ plugin: ["context-mode"], version: "1.0" });
+      rmSync(root, { recursive: true, force: true });
+    });
+
+    it("prefers opencode.json over opencode.jsonc when both exist", () => {
+      const root = mkdtempSync(join(tmpdir(), "opencode-adapter-"));
+      const dir = join(root, "project");
+      const src = resolve(process.cwd(), "src", "adapters", "opencode", "index.ts");
+      const tsx = resolve(process.cwd(), "node_modules", "tsx", "dist", "cli.mjs");
+      mkdirSync(dir, { recursive: true });
+      writeFileSync(join(dir, "opencode.json"), JSON.stringify({ from: "json" }));
+      writeFileSync(join(dir, "opencode.jsonc"), `{ /* comment */ "from": "jsonc" }`);
+      const run = spawnSync(
+        process.execPath,
+        [
+          tsx,
+          "-e",
+          `import { OpenCodeAdapter } from ${JSON.stringify(src)};const a=new OpenCodeAdapter();console.log(JSON.stringify(a.readSettings()))`,
+        ],
+        { cwd: dir, env: env(join(root, "home")), encoding: "utf-8" },
+      );
+      expect(run.status).toBe(0);
+      expect(JSON.parse(run.stdout)).toEqual({ from: "json" });
+      rmSync(root, { recursive: true, force: true });
+    });
+
+    it("configureAllHooks works with opencode.jsonc", () => {
+      const root = mkdtempSync(join(tmpdir(), "opencode-adapter-"));
+      const dir = join(root, "project");
+      const src = resolve(process.cwd(), "src", "adapters", "opencode", "index.ts");
+      const tsx = resolve(process.cwd(), "node_modules", "tsx", "dist", "cli.mjs");
+      mkdirSync(dir, { recursive: true });
+      writeFileSync(
+        join(dir, "opencode.jsonc"),
+        `{
+  // My config
+  "plugin": []
+}
+`,
+      );
+      const run = spawnSync(
+        process.execPath,
+        [
+          tsx,
+          "-e",
+          `import { OpenCodeAdapter } from ${JSON.stringify(src)};const a=new OpenCodeAdapter();console.log(JSON.stringify(a.configureAllHooks('/tmp/plugin')))`,
+        ],
+        { cwd: dir, env: env(join(root, "home")), encoding: "utf-8" },
+      );
+      expect(run.status).toBe(0);
+      expect(JSON.parse(run.stdout)).toEqual(["Added context-mode to plugin array"]);
+      // Should write back to .jsonc (same file it read)
+      expect(JSON.parse(readFileSync(join(dir, "opencode.jsonc"), "utf-8"))).toEqual({
+        plugin: ["context-mode"],
+      });
+      rmSync(root, { recursive: true, force: true });
+    });
+
+    it("validates hooks with jsonc config shows correct error message", () => {
+      const root = mkdtempSync(join(tmpdir(), "opencode-adapter-"));
+      const dir = join(root, "project");
+      const src = resolve(process.cwd(), "src", "adapters", "opencode", "index.ts");
+      const tsx = resolve(process.cwd(), "node_modules", "tsx", "dist", "cli.mjs");
+      mkdirSync(dir, { recursive: true });
+      // No config file at all
+      const run = spawnSync(
+        process.execPath,
+        [
+          tsx,
+          "-e",
+          `import { OpenCodeAdapter } from ${JSON.stringify(src)};const a=new OpenCodeAdapter();console.log(JSON.stringify(a.validateHooks('/tmp')))`,
+        ],
+        { cwd: dir, env: env(join(root, "home")), encoding: "utf-8" },
+      );
+      expect(run.status).toBe(0);
+      const results = JSON.parse(run.stdout);
+      const pluginCheck = results.find((r: { check: string }) => r.check === "Plugin configuration");
+      expect(pluginCheck.message).toContain("jsonc");
+      rmSync(root, { recursive: true, force: true });
+    });
+
     it("configureAllHooks writes back to .opencode/opencode.json when that is the selected config", () => {
       const root = mkdtempSync(join(tmpdir(), "opencode-adapter-"));
       const dir = join(root, "project");