Increase Codex CLI context window to match ~400k model capacity
Resolved 💬 2 comments Opened Jan 25, 2026 by dismonjames Closed Jan 25, 2026
💡 Likely answer: A maintainer (github-actions[bot], contributor)
responded on this thread — see the highlighted reply below.
What feature would you like to see?
Expose the full context window of the underlying gpt-5.2-codex model (~400k tokens) in the Codex CLI, or provide a config/flag to enable higher limits.
Additional information
Right now the Codex CLI seems capped at ~258k tokens, while the model itself supports ~400k. Not sure if this limitation comes from the CLI layer, the client-side streaming protocol, memory constraints, or a temporary safety limit. Would love clarification on why the CLI exposes only ~258k, and whether matching the full ~400k context is planned or technically feasible.
For real-world codebases (multi-repo, long-range refactoring, persistent editing), the extra context would make a big difference.
2 Comments
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
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@etraut-openai Codex Action already flagged #9429 here, and this seems like the same request (raise the effective context window / expose more of the ~400k model capacity).
Suggestion: close #9857 as a duplicate and consolidate discussion + votes on #9429.