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OpenAI · model passport

OpenAI: GPT-5.1-Codex-Max

gpt-5-1-codex
  • Cloud only
  • Proprietary licence
  • 400,000 context
  • Released 2026-10-13(first seen on LMArena)
6/27axes covered
Best percentile
95.4LiveCodeBench (Artificial Analysis)
Cohort standing
67.7median 60.6

What the data says

Benchmarked on 6 of 27 tracked axes. Every figure below is the model's own published result on that board.

Strongest axes

  • 95.4 pct — LiveCodeBench (Artificial Analysis) (84.9%)
  • 94.5 pct — LiveBench (75.6%)
  • 94.4 pct — MMLU-Pro (Artificial Analysis) (86.0%)

Uneven: 74.5 percentile points between its best and worst axis — 95.4 pct on LiveCodeBench (Artificial Analysis) versus 20.9 pct on WebDev Arena.

  • LiveCodeBench (Artificial Analysis)95.4 pct84.9%Verify →
  • LiveBench94.5 pct75.6%Verify →
  • MMLU-Pro (Artificial Analysis)94.4 pct86.0%Verify →
  • IFBench (Artificial Analysis)81.8 pct70.0%Verify →
  • Terminal-Bench72.7 pct60.4%Verify →
  • WebDev Arena20.9 pct1,337Verify →
  • OverallNot benchmarked
  • Vision ArenaNot benchmarked
  • Factuality ArenaNot benchmarked
  • Search ArenaNot benchmarked
  • Document ArenaNot benchmarked
  • Agent ArenaNot benchmarked
  • GPQA DiamondNot benchmarked
  • AIME (math)Not benchmarked
  • FrontierMathNot benchmarked
  • SimpleQA VerifiedNot benchmarked
  • ARC-AGI-2Not benchmarked
  • Humanity's Last ExamNot benchmarked
  • SimpleBenchNot benchmarked
  • BFCL v4 (function calling)Not benchmarked
  • SWE-bench Verified (live board)Not benchmarked
  • Terminal-Bench 4.0Not benchmarked
  • HHEM Hallucination (Vectara)Not benchmarked
  • SWE-bench VerifiedNot benchmarked
  • CodingNot benchmarked
  • Instruction followingNot benchmarked
  • Hard promptsNot benchmarked

Percentiles are the model's standing within each board's own population. Axes marked "not benchmarked" have no published result for this model — that is an absence of data, not a low score.

How to run it

Use it hosted

API model IDopenai/gpt-5.1-codex-max
Context length400,000 tokens
Max output128,000 tokens
Acceptstext, image
Input price$1.25 per 1M tokens
Cached input price$0.13 per 1M tokens
Output price$10 per 1M tokens

API parameters this endpoint supports

Include reasoningMax completion tokensReasoningReasoning effortResponse formatSeedStructured outputsTool choiceTool callingVerbosity

Example request

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-5.1-codex-max","messages":[{"role":"user","content":"Hello"}]}'

View on OpenRouter →

Identifiers, limits and prices are synced from the upstream source shown above. Any field we haven't synced is left out entirely rather than guessed.

  • GPT-5.1-Codex stands at 67.7 (raw mean 76.6) — measured on 6 of 27 axes.

    standingtemplateVerify →

  • GPT-5.1-Codex stands at 67.7 versus a cohort median of 60.6 across 168 models released within 180 days — above the peer median.

    cohorttemplateVerify →

Every claim is a computed fact from the current board data, phrased by a low-temperature model call and rejected by a validation gate if any number is not in the source row. How the leaderboards work →