# NousResearch/hermes-agent · gpt-5.3-codex model unsupported or removed from Codex catalog

## Open now

- Nothing open on GitHub.

One bug report describes a 400 error saying 'gpt-5.3-codex' is not supported when using Codex. Two pull requests propose removing that model from the Codex catalog and the curated fallback list, apparently because it is retired; their outcome is not established here.

## TL;DR

- 3 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #115879. Verify it addresses your case.
- **Recommended:** read PR #115879 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-115879`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.67`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #52492: \[Bug\]:400 - 'gpt-5.3-codex' model is not supported when using Codex

## Prior & competing PRs

- **#115879: fix(codex): retired gpt-5.3-codex no longer offered in the Codex model catalog (#52492, salvage #52509)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `hermes_cli/cli_model_switch_mixin.py`, `hermes_cli/codex_models.py`, `run_agent.py`, `tests/agent/test_codex_silent_hang_hint.py`, `tests/agent/test_codex_ttfb_watchdog.py`, `tests/hermes_cli/test_codex_models.py`, `website/docs/user-guide/configuration.md`, `website/docs/user-guide/features/fallback-providers.md`, `website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/configuration.md`, `website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/fallback-providers.md`
- **#52509: fix(codex): remove dead gpt-5.3-codex from curated fallback list (#52492)**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `3934fe551cf0`, `#115879`, `#52492`, `#52509`

## Fix status

- Merged to main in PR #115879 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-19`.
- Subsystem: `agent`