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Code

GPT-5.1-Codex

By OpenAI, in the Codex family.

Released: 13 Nov 2025
Status: Retired
Retired: 23 Jul 2026
Context: 400K
Max output: 128K
Input per 1M tokens: $1.25
Output per 1M tokens: $10.00
Open weights: No
License: proprietary
Parameters: —
Knowledge cutoff: 30 Sep 2024
Reasoning: Yes
Modalities: text, image → text

Category scores

Out of 100, from independent and third-party results only, by method category-2026-09-29.1.

Category scores
Category	Score	Rank	Coverage
Human preference	41.0	Not ranked	1 of 5

Benchmark results

Every result we hold for this model, with who ran it and where it was published.

Coding & software engineering

Coding & software engineering results
Benchmark	Metric	Value	Provenance	Setting	Evaluated	Source
Terminal-Bench 2.0	Accuracy (mean over trials)	57.8%	Third party	—	—	Terminal-Bench v2 Leaderboard via Epoch AI
Terminal-Bench 2.0	Accuracy (mean over trials)	57.8%	Third party	—	—	https://www.tbench.ai/leaderboard/terminal-bench/2.0 via Epoch AI
Terminal-Bench 2.0	Accuracy (mean over trials)	53.5%	Third party	—	—	https://www.tbench.ai/leaderboard/terminal-bench/2.0 via Epoch AI
Terminal-Bench 2.0	Accuracy (mean over trials)	36.9%	Third party	—	—	Terminal-Bench v2 Leaderboard via Epoch AI
Terminal-Bench 2.0	Accuracy (mean over trials)	36.9%	Third party	—	—	https://www.tbench.ai/leaderboard/terminal-bench/2.0 via Epoch AI

Human preference

Human preference results
Benchmark	Metric	Value	Provenance	Setting	Evaluated	Source
Code Arena: WebDev (arena.ai)	Arena score (Elo scale)	1337	Independent	—	25 Sep 2026	Arena
Code Arena: WebDev (arena.ai)	Votes	5012	Independent	—	25 Sep 2026	Arena

Other Codex versions

Sources