fix(cloud-agent): inject prContext into codex prompts

packages/agent/src/adapters/codex/codex-agent.test.ts

@@ -127,6 +127,46 @@ describe("CodexAcpAgent", () => {
     ).toBe("read-only");
   });
 
+  it("prepends _meta.prContext to the forwarded prompt but not to the broadcast", async () => {
+    const { agent, client } = createAgent();
+    mockCodexConnection.newSession.mockResolvedValue({
+      sessionId: "session-1",
+      modes: { currentModeId: "auto", availableModes: [] },
+      configOptions: [],
+    } satisfies Partial<NewSessionResponse>);
+    await agent.newSession({
+      cwd: process.cwd(),
+    } as never);
+
+    mockCodexConnection.prompt.mockResolvedValue({ stopReason: "end_turn" });
+
+    await agent.prompt({
+      sessionId: "session-1",
+      prompt: [{ type: "text", text: "ship the fix" }],
+      _meta: { prContext: "PR #123 is open; review before editing." },
+    } as never);
+
+    // codex-acp receives the PR context prepended as a text block.
+    expect(mockCodexConnection.prompt).toHaveBeenCalledWith(
+      expect.objectContaining({
+        prompt: [
+          { type: "text", text: "PR #123 is open; review before editing." },
+          { type: "text", text: "ship the fix" },
+        ],
+      }),
+    );
+    // The broadcast shows only the real user turn — the prContext prefix
+    // is internal routing and should not render as a user message.
+    expect(client.sessionUpdate).toHaveBeenCalledTimes(1);
+    expect(client.sessionUpdate).toHaveBeenCalledWith({
+      sessionId: "session-1",
+      update: {
+        sessionUpdate: "user_message_chunk",
+        content: { type: "text", text: "ship the fix" },
+      },
+    });
+  });
+
   it("broadcasts user prompt as user_message_chunk before delegating to codex-acp", async () => {
     const { agent, client } = createAgent();
     // Seed an active session so prompt() has the state it expects.

packages/agent/src/adapters/codex/codex-agent.ts

@@ -93,6 +93,24 @@ function toCodexPermissionMode(mode?: string): PermissionMode {
   return "auto";
 }
 
+/**
+ * Prepend `_meta.prContext` (set by the agent-server on Slack-originated
+ * follow-up runs) to the prompt as a text block, mirroring Claude's
+ * `promptToClaude` behavior. Without this, codex cloud runs lose the
+ * PR-review context that follow-up flows rely on.
+ */
+function prependPrContext(params: PromptRequest): PromptRequest {
+  const prContext = (params._meta as Record<string, unknown> | undefined)
+    ?.prContext;
+  if (typeof prContext !== "string" || prContext.length === 0) {
+    return params;
+  }
+  return {
+    ...params,
+    prompt: [{ type: "text", text: prContext }, ...params.prompt],
+  };
+}
+
 const CODEX_NATIVE_MODE: Record<CodeExecutionMode, CodexNativeMode> = {
   default: "auto",
   acceptEdits: "auto",
@@ -373,9 +391,13 @@ export class CodexAcpAgent extends BaseAcpAgent {
     // channel, so without this broadcast the tapped stream (persisted to S3
     // and rendered by the PostHog web UI) never sees a user turn and only
     // the assistant reply shows up. Mirrors ClaudeAcpAgent.broadcastUserMessage.
+    // The original params (no _meta.prContext prefix) is broadcast so the
+    // injected PR context is not rendered as a user message.
     await this.broadcastUserMessage(params);
 
-    const response = await this.codexConnection.prompt(params);
+    const response = await this.codexConnection.prompt(
+      prependPrContext(params),
+    );
 
     // Usage is already accumulated via sessionUpdate notifications in
     // codex-client.ts. Do NOT also add response.usage here or tokens