Investigation: Codex VS Code Extension

[Created by Codex: 019be564-39d9-7b12-a4cf-fb7a7f1af223 2026-01-22]

Purpose

Provide a fast, repeatable workflow to diagnose why the Codex VS Code extension cannot spawn or connect to the local codex app-server.

Use when a user reports that Codex in VS Code will not start, errors on spawn, or fails after an extension or CLI update.

Non-default CLI override is set: If "chatgpt.cliExecutable" is configured, the extension will run that binary instead of the bundled 45MB codex.
Assume “custom build” risk: An override often points at a locally built or modified Codex repo; the user must know exactly what it is and why it differs.
Always surface it explicitly: State the resolved codex path and codex --version in the RCA, and ask the user to confirm the repo/build they intended to run.

Symptom: “Cannot spawn a Codex agent in VS Code” after updating the extension to openai.chatgpt 0.4.62.
Root cause: The extension started codex app-server --analytics-default-enabled, but the user had "chatgpt.cliExecutable" pinned to a codex-cli 0.77.0 binary that did not recognize that flag, so the process exited with code 2.
Evidence: ~/Library/Application Support/Code/logs/.../window*/exthost/openai.chatgpt/Codex.log contained error: unexpected argument '--analytics-default-enabled' found.
Fix: Remove or update "chatgpt.cliExecutable" to a compatible codex binary (or let the extension use its bundled one), then reload VS Code.