OpenAI Codex breaking changes, updated weekly

Every verified OpenAI Codex trap in Footgun: changes and behaviors that break code or give wrong results, newest first. Each one has the error you see, the fix, and the date it was last checked. The list updates when the weekly check adds or retires a trap. For the full cause and sources, open the trap, or see all OpenAI Codex traps.

1. fg-0497· added 2026-10-15· last checked 2026-10-15

   codex exec exits 1 with 'Not inside a trusted directory and --skip-git-repo-check was not specified'

   Symptom

   Not inside a trusted directory and --skip-git-repo-check was not specified.

   Fix

   Run inside a Git repository (git init works for scratch workspaces), or add --skip-git-repo-check in an environment you control.

2. fg-0498· added 2026-10-15· last checked 2026-10-15

   codex exec in CI finishes but changes no files

   Symptom

   The final message describes edits, but git diff is empty

   Fix

   Pass --sandbox workspace-write for runs that edit, or danger-full-access only on an isolated runner.

3. fg-0500· added 2026-10-15· last checked 2026-10-15

   Codex fails to start because config.toml still sets approval_policy = "untrusted"

   Symptom

   Error loading configuration: approval_policy = "untrusted" is no longer supported; remove this setting

   Fix

   Remove the setting everywhere it appears. For read-only interactive use set read-only with on-request, or keep the stricter behavior by marking the project untrusted in user config and leaving approval_policy unset.

4. fg-0503· added 2026-10-15· last checked 2026-10-15

   Codex shell commands cannot reach the network in workspace-write, so npm install and curl fail

   Symptom

   npm install, pip install, or curl fails with DNS or connection errors inside Codex

   Fix

   Set network_access true under sandbox_workspace_write, and add network_proxy rules if you want an allowlist. Some Codex App versions have been reported to ignore the key, so test from the CLI first.

5. fg-0505· added 2026-10-15· last checked 2026-10-15

   git commit fails inside Codex's workspace-write sandbox because .git is read-only

   Symptom

   git commit, git checkout, or git stash fail with a permission error inside Codex

   Fix

   Let Codex edit files and run git yourself, approve an escalation for the git command, or use danger-full-access only in an isolated environment.

6. fg-0495· added 2026-10-15· last checked 2026-10-15

   Codex does not read the repo's CLAUDE.md or other existing instruction files

   Symptom

   Codex ignores rules that Claude Code follows from CLAUDE.md

   Fix

   List the extra filenames in config.toml, or add an AGENTS.md that points to the shared file.

7. fg-0496· added 2026-10-15· last checked 2026-10-15

   Codex drops later AGENTS.md instructions once project guidance passes 32 KiB

   Symptom

   Rules from the AGENTS.md closest to the working directory are missing

   Fix

   Raise project_doc_max_bytes in config.toml, or trim the root file and move detail into nested files.

8. fg-0499· added 2026-10-15· last checked 2026-10-15

   Codex fails to load its config when a model provider still sets wire_api = "chat"

   Symptom

   failed to load Codex config, and codex doctor reports config could not be loaded

   Fix

   Point the provider at a Responses-compatible endpoint with wire_api responses, put a Responses-compatible gateway in front of the old one, or delete the stale provider entry.

9. fg-0501· added 2026-10-15· last checked 2026-10-15

   Codex ignores AGENTS.md files in folders below the directory it was started from

   Symptom

   Rules in packages/api/AGENTS.md are not followed when Codex starts at the repo root

   Fix

   Start Codex in the folder whose rules apply with --cd, keep shared rules in the root AGENTS.md, and restart after changing instructions.

10. fg-0502· added 2026-10-15· last checked 2026-10-15

    codex login on a remote or headless machine never completes the browser sign-in

    Symptom

    Browser sign-in started over SSH never returns to Codex

    Fix

    Enable device code login and run codex login --device-auth, or sign in on a machine with a browser and copy ~/.codex/auth.json when file credential storage is used. For automation, pipe an API key to codex login --with-api-key.

11. fg-0504· added 2026-10-15· last checked 2026-10-15

    Codex starts the first turn without tools from a slow MCP server

    Symptom

    Tools from an MCP server are missing on the first prompt but appear later

    Fix

    Raise startup_timeout_sec for slow servers, mark servers the task depends on as required, or set the grace to 0 to wait for each server's own timeout.

12. fg-0506· added 2026-10-15· last checked 2026-10-15

    Settings in a repo's .codex/config.toml are ignored by Codex

    Symptom

    sandbox_mode or model set in the project .codex/config.toml has no effect

    Fix

    Trust the project when Codex asks, or mark it trusted in user config.

13. fg-0507· added 2026-10-15· last checked 2026-10-15

    'The model is not supported when using Codex with a ChatGPT account' after a model retirement

    Symptom

    The 'gpt-5.6-sol' model is not supported when using Codex with a ChatGPT account.

    Fix

    Replace retired model ids in config.toml, profiles, custom agents, scheduled tasks, and scripts with a model available to your plan, and check that the subscription is active.