From 058e65d9202ea808cfb51be6ce9842feb6f5b67a Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <219906144+aibrahim-oai@users.noreply.github.com>
Date: Tue, 17 Mar 2026 17:16:18 +0000
Subject: [PATCH] Fix code mode yield startup race

Start the initial yield timer only after the worker reports that code execution has started, so worker startup jitter on loaded CI runners does not consume the yield budget before user code runs.

Co-authored-by: Codex <noreply@openai.com>
---
 codex-rs/core/src/tools/code_mode/runner.cjs | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/codex-rs/core/src/tools/code_mode/runner.cjs b/codex-rs/core/src/tools/code_mode/runner.cjs
index 9ebb9c98820..48b9d5a9af1 100644
--- a/codex-rs/core/src/tools/code_mode/runner.cjs
+++ b/codex-rs/core/src/tools/code_mode/runner.cjs
@@ -465,6 +465,7 @@ function codeModeWorkerMain() {
       writable: false,
     });
 
+    parentPort.postMessage({ type: 'started' });
     try {
       await runModule(context, start, callTool, helpers);
       parentPort.postMessage({
@@ -639,6 +640,10 @@ function startSession(protocol, sessions, start) {
     content_items: [],
     default_yield_time_ms: normalizeYieldTime(start.default_yield_time_ms),
     id: start.cell_id,
+    initial_yield_time_ms:
+      start.yield_time_ms == null
+        ? normalizeYieldTime(start.default_yield_time_ms)
+        : normalizeYieldTime(start.yield_time_ms),
     initial_yield_timer: null,
     initial_yield_triggered: false,
     max_output_tokens_per_exec_call: maxOutputTokensPerExecCall,
@@ -651,11 +656,6 @@ function startSession(protocol, sessions, start) {
     }),
   };
   sessions.set(session.id, session);
-  const initialYieldTime =
-    start.yield_time_ms == null
-      ? session.default_yield_time_ms
-      : normalizeYieldTime(start.yield_time_ms);
-  scheduleInitialYield(protocol, session, initialYieldTime);
 
   session.worker.on('message', (message) => {
     void handleWorkerMessage(protocol, sessions, session, message).catch((error) => {
@@ -694,6 +694,11 @@ async function handleWorkerMessage(protocol, sessions, session, message) {
     return;
   }
 
+  if (message.type === 'started') {
+    scheduleInitialYield(protocol, session, session.initial_yield_time_ms);
+    return;
+  }
+
   if (message.type === 'yield') {
     void sendYielded(protocol, session);
     return;