Models · OpenAI · Out sinceReleased 4 Dec 2025

GPT-5.1-Codex-Max

Available on OpenRouterOn OpenRouterAvailable nowGenerally availableClosed (can't be downloaded)Proprietary

GPT-5.1-Codex-Max is made by OpenAI. We don't have enough test results yet to rank it. It's mid-priced to use.

Auto-created from OpenRouter catalog; verify details.

Writing & creativity: —
Research & analysis: —
Coding: —
Price: Mid-priced$1.25 / $10
Price per 1M (blended)Blended / 1M: $3.44
MemoryContext: 400K
Longest answerMax output: —
Test resultsResults: 1 (1 independent1 indep.)
Out sinceReleased: 4 Dec 2025
Made byVendor: OpenAI
UnderstandsInputs: —

Scores are out of 100 for each area, compared with every model we track; “#” is its rank. Context is how much text it can read at once (1M is roughly 700,000 words). Blended price mixes the cost of what you send and what it writes back.

Thinking levels

Reasoning settings

You can't choose how long this one thinks.

No adjustable reasoning setting listed.

Links

Using it through OpenRouter

On OpenRouter

OpenRouter is a service that gives access to many AI models in one place. This model is listed there as openai/gpt-5.1-codex-max.

Route it as openai/gpt-5.1-codex-max at $1.25 in / $10 out per 1M tokens, 400K context. Listed since 4 Dec 2025.

include_reasoningmax_completion_tokensreasoningreasoning_effortresponse_formatseedstructured_outputstool_choicetools

Every test result

Every result

All the numbers,with where they came from.

Every result we've found for this model, with who measured it and a link to where we read it.

All raw rows (vendor and independent kept separate), with setting label, source, date, harness and notes.

All results for this model
						NotesNotes
METR 50% time horizon	3.7 h	Default	Independent testIndependentMETR ↗	8 May 2026	METR react agent (Inspect)	50% time horizon, METR-Horizon-v1.1; 95% CI 134-396 min; 80% horizon 50.6 min; release 2025-11-19; raw data https://metr.org/assets/benchmark_results_1_1.yaml