Fix Codex annotate-last message selection (#740)

Author: mu-hashmi

apps/hook/server/codex-session.test.ts

@@ -310,6 +310,43 @@ describe("getLastCodexMessage", () => {
     expect(result).not.toBeNull();
     expect(result!.text).toBe("Valid message");
   });
+
+  test("can ignore assistant messages from the active Codex turn", () => {
+    const previousTurnId = "turn-previous";
+    const activeTurnId = "turn-active";
+    const path = writeTempRollout(
+      buildRollout(
+        sessionMeta(),
+        turnStarted(previousTurnId),
+        userMessage("Explain the thing"),
+        assistantMessage("Substantive final answer"),
+        turnCompleted(previousTurnId),
+        turnStarted(activeTurnId),
+        userMessage("[$plannotator-last]"),
+        assistantMessage("I’ll open Plannotator on my last response.")
+      )
+    );
+
+    const result = getLastCodexMessage(path, { beforeActiveTurn: true });
+    expect(result).not.toBeNull();
+    expect(result!.text).toBe("Substantive final answer");
+  });
+
+  test("keeps default latest-message behavior inside an active turn", () => {
+    const turnId = "turn-active";
+    const path = writeTempRollout(
+      buildRollout(
+        sessionMeta(),
+        assistantMessage("Previous answer"),
+        turnStarted(turnId),
+        assistantMessage("Current status update")
+      )
+    );
+
+    const result = getLastCodexMessage(path);
+    expect(result).not.toBeNull();
+    expect(result!.text).toBe("Current status update");
+  });
 });
 
 describe("getLatestCodexPlan", () => {

apps/hook/server/codex-session.ts

@@ -48,12 +48,17 @@ export interface CodexPlanResult {
   source: CodexPlanSource;
 }
 
+export interface GetLastCodexMessageOptions {
+  beforeActiveTurn?: boolean;
+}
+
 export interface GetLatestCodexPlanOptions {
   turnId?: string;
   stopHookActive?: boolean;
 }
 
 const TURN_START_TYPES = new Set(["task_started", "turn_started"]);
+const TURN_COMPLETE_TYPES = new Set(["task_complete", "turn_completed"]);
 const PROPOSED_PLAN_RE = /<proposed_plan>([\s\S]*?)<\/proposed_plan>/gi;
 
 // --- Rollout File Discovery ---
@@ -200,6 +205,24 @@ function findTurnStartIndex(entries: RolloutEntry[], turnId?: string): number {
   return lastTurnContext === -1 ? 0 : lastTurnContext;
 }
 
+function findActiveTurnStartIndex(entries: RolloutEntry[]): number {
+  const latestTurnStart = findLastIndex(
+    entries,
+    (entry) =>
+      entry.type === "event_msg" &&
+      TURN_START_TYPES.has(entry.payload?.type || "")
+  );
+  if (latestTurnStart === -1) return -1;
+
+  const latestTurnComplete = findLastIndex(
+    entries,
+    (entry) =>
+      entry.type === "event_msg" &&
+      TURN_COMPLETE_TYPES.has(entry.payload?.type || "")
+  );
+  return latestTurnStart > latestTurnComplete ? latestTurnStart : -1;
+}
+
 function isHookPromptMessage(entry: RolloutEntry): boolean {
   if (entry.type !== "response_item") return false;
   if (entry.payload?.type !== "message") return false;
@@ -295,12 +318,17 @@ function pickLatestPreferredPlan(
  * Extracts output_text blocks from payload.content.
  */
 export function getLastCodexMessage(
-  rolloutPath: string
+  rolloutPath: string,
+  options: GetLastCodexMessageOptions = {}
 ): { text: string } | null {
   const entries = parseRolloutEntries(rolloutPath);
+  const activeTurnStart = options.beforeActiveTurn
+    ? findActiveTurnStartIndex(entries)
+    : -1;
+  const endIndex = activeTurnStart === -1 ? entries.length - 1 : activeTurnStart - 1;
 
   // Walk backward
-  for (let i = entries.length - 1; i >= 0; i--) {
+  for (let i = endIndex; i >= 0; i--) {
     const entry = entries[i];
     if (entry.type !== "response_item") continue;
     if (entry.payload?.type !== "message") continue;

apps/hook/server/index.ts

@@ -771,7 +771,7 @@ if (args[0] === "sessions") {
       if (process.env.PLANNOTATOR_DEBUG) {
         console.error(`[DEBUG] Rollout: ${rolloutPath}`);
       }
-      const msg = getLastCodexMessage(rolloutPath);
+      const msg = getLastCodexMessage(rolloutPath, { beforeActiveTurn: true });
       if (msg) {
         lastMessage = { messageId: codexThreadId, text: msg.text, lineNumbers: [] };
       }

apps/skills/plannotator-last/SKILL.md

@@ -7,6 +7,10 @@ description: Open Plannotator on the latest rendered assistant message and use t
 
 Use this skill when the user wants to annotate the latest assistant response in Plannotator.
 
+Do not send a commentary/status message before running the command. The command
+targets the latest rendered assistant response, so a preamble can mistakenly become the
+thing being annotated.
+
 Run:
 
 ```bash