feat: add Codex thread reference tools

.github/workflows/ci.yml

@@ -25,7 +25,27 @@ jobs:
         run: npm ci
       - name: Typecheck
         run: npm run typecheck
+      - name: Check generated app-server types
+        run: npm run check:generated-types
       - name: Run unit tests
         run: npm test
       - name: Bundle binaries
         run: npm run bundle:all
+
+  node-20:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
+        with:
+          node-version: "20"
+      - name: Install dependencies
+        run: npm ci
+      - name: Typecheck
+        run: npm run typecheck
+      - name: Run unit tests
+        run: npm test
+      - name: Build
+        run: npm run build

.github/workflows/codex-update.yml

@@ -76,7 +76,7 @@ jobs:
 
       - name: Install new version of package and commit
         run: |
-          npm install "$CODEX_PACKAGE@$VERSION"
+          npm install --save-exact "$CODEX_PACKAGE@$VERSION"
           npm run generate-types
           git add package.json package-lock.json src/app-server
           git commit -m "fix: update codex to $VERSION"

README.md

@@ -11,6 +11,7 @@ Use [OpenAI Codex](https://github.com/openai/codex) from [Agent Client Protocol]
 - ChatGPT, API key, and client-provided custom gateway authentication.
 - Model, reasoning effort, fast mode, approval, and sandbox mode configuration.
 - Text prompts, embedded context, images, resource links, and additional workspace directories.
+- [Cross-session references](docs/session-references.md) that use Codex thread deep links.
 - Shell command, file change, [permission request](docs/permission-extension.md), MCP tool call, terminal output, reasoning, plan, web search, image generation, image view, token usage, and review events.
 - [Native ACP subagent sessions](docs/subagent-sessions.md) (after capability negotiation) with separate child histories and root-routed permissions; a legacy tool-call fallback otherwise.
 - Session-scoped long-running goals through the provider-neutral [goal extension](docs/goal-extension.md).

docs/session-references.md

@@ -0,0 +1,19 @@
+# Cross-session references
+
+The adapter recognizes an ACP `resource_link` with this URI form:
+
+```text
+acp-session://reference?sessionId=<Codex thread ID>
+```
+
+The client can add query parameters for navigation. The adapter reads only `sessionId`.
+
+The adapter passes the thread ID and `codex://threads/<Codex thread ID>` to Codex.
+It tells Codex to call `read_thread` before it uses the referenced content.
+
+The adapter does not pass the link title. It does not copy the referenced session into the prompt.
+The private MCP server reads the session only when Codex calls a thread tool.
+
+The adapter preserves the order and number of links. It leaves other resource links unchanged.
+
+See [`src/thread-tools-mcp/README.md`](../src/thread-tools-mcp/README.md) for the MCP server design.