OpenAI Codex release notes: 0.155.1 fixes rejected requests

OpenAI Codex CLI 0.155.1 fixes a bug that could cause model providers to reject requests. New local sessions no longer request reasoning summaries by default. Codex CLI is OpenAI's terminal-based coding agent; reasoning summaries describe the model's reasoning.

OpenAI Codex release notes: corrected default in 0.155.1

In version 0.155, new local sessions in the terminal interface requested detailed reasoning summaries. Providers that do not support these summaries could reject the request.

Patch 0.155.1, published on September 18, restores the default to none. If you explicitly selected auto, concise, or detailed, Codex still respects that choice. Updating does not override a custom setting that requests summaries.

Source: OpenAI Codex CLI 0.155.1 release notes.

Source: OpenAI: Restore none as the TUI reasoning summary default.

Human step: update Codex CLI

For npm installations, OpenAI provides this command:

npm install -g @openai/[email protected]

Source: OpenAI Codex changelog.

The fix applies to the default for new local sessions. It needs no special agent prompt. If your provider does not support summaries, also check whether you explicitly enabled them: that choice survives the update.