Overview

Identity

Identity block not returned by the API for this entity.

Openness

Openness not classified yet — no sourced evidence to place this model in the ontology.

Key facts

Release date: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium
Status: Source:OpenAI Platform docsT1observed 13 h agohigh
Deprecation date: Source:OpenAI Platform docsT1observed 13 h agohigh
Retirement date: Source:OpenAI Platform docsT1observed 13 h agohigh
Official page: developers.openai.com/api/docs/models/gpt-5.1-codex-max
Source:OpenAI Platform docsT1observed 13 h agohigh
API model id: Source:OpenAI Platform docsT1observed 13 h agohigh
Openrouter id: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium

Architecture

Tokenizer: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium

Capabilities

Modalities

Modalities: imagetext
Input: imagetext
Output: text

Capabilities

Tool calling
Yes
OpenRouter public model & pricing listing · T2
Structured output
Yes
OpenRouter public model & pricing listing · T2
Reasoning
Yes
OpenRouter public model & pricing listing · T2
Vision
Yes
OpenRouter public model & pricing listing · T2
Audio
Unavailable
Fine-tuning available
Unavailable

Context window: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium
Max output: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium
Tokenizer: Source:OpenRouter public model & pricing listingT2observed 13 h agomedium

Providers & Pricing1

All offers in the price terminal →

Current prices per 1M tokens
Provider	Input / 1M	Output / 1M	Cached in	Batch in / out	Context	Observed	Source
OpenAI APIopenai/gpt-5.1-codex-max	$1.25	$10	$0.125	—	400K	13 h ago	openrouter.aiT2

USD per 1M tokens as published by each provider (USD). Rows are append-only: every change is kept in the history below.

Price history

Step lines per provider; amber markers are recorded changes. Click a marker or a row for the evidence behind that price.

Output price · USD / 1M tokens 1 provider

Price history starts with the first observation — no change recorded yet for this side (1 row).

OpenAI APIfirst observed $1011 Sept 2026

Input price · USD / 1M tokens 1 provider

Price history starts with the first observation — no change recorded yet for this side (1 row).

OpenAI APIfirst observed $1.2511 Sept 2026

Timeline2

Full timeline →

11 Sept 2026
Listed by providerModelGPT-5.1-Codex-MaxOpenAI
OpenAI API lists GPT-5.1-Codex-Max at $1.25 in / $10 out per 1M tokens
openrouter
openrouter.ai
11 Sept 2026
New modelModelGPT-5.1-Codex-MaxOpenAI
New model: GPT-5.1-Codex-Max (OpenAI)
openai
developers.openai.com

Change history21

Temporal, append-only claims: a new observation closes the previous claim instead of overwriting it. Rewind the record with the as-of picker.

Viewing AI Atlas as of 12 Mar 2026 — attributes exactly as the atlas knew them on that day; later corrections are not shown.

Back to today →

GPT-5.1-Codex-Max was not yet in AI Atlas on 12 Mar 2026

First seen 11 Sept 2026. Nothing is inferred backwards: no attribute is shown for dates before the first observation.

21 claims · 21 properties

Release daterelease_date1

Claim history for Release date
Value	Valid from → to	Status	Source	Confidence	Extractor
4 Dec 2025	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Statusstatus1

Claim history for Status
Value	Valid from → to	Status	Source	Confidence	Extractor
retired	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Opennessopenness1

Claim history for Openness
Value	Valid from → to	Status	Source	Confidence	Extractor
proprietary	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Context windowcontext_length1

Claim history for Context window
Value	Valid from → to	Status	Source	Confidence	Extractor
400K tokens	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Max outputmax_output_tokens1

Claim history for Max output
Value	Valid from → to	Status	Source	Confidence	Extractor
128K tokens	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Modalitiesmodalities1

Claim history for Modalities
Value	Valid from → to	Status	Source	Confidence	Extractor
image, text	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Input modalitiesmodalities_input1

Claim history for Input modalities
Value	Valid from → to	Status	Source	Confidence	Extractor
image, text	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Output modalitiesmodalities_output1

Claim history for Output modalities
Value	Valid from → to	Status	Source	Confidence	Extractor
text	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Tokenizertokenizer1

Claim history for Tokenizer
Value	Valid from → to	Status	Source	Confidence	Extractor
GPT	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

API model idapi_model_id1

Claim history for API model id
Value	Valid from → to	Status	Source	Confidence	Extractor
gpt-5.1-codex-max	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Deprecation datedeprecation_date1

Claim history for Deprecation date
Value	Valid from → to	Status	Source	Confidence	Extractor
22 Apr 2026	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Retirement dateretirement_date1

Claim history for Retirement date
Value	Valid from → to	Status	Source	Confidence	Extractor
23 Jul 2026	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Retirement tentativeretirement_tentative1

Claim history for Retirement tentative
Value	Valid from → to	Status	Source	Confidence	Extractor
No	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Official pageofficial_url1

Claim history for Official page
Value	Valid from → to	Status	Source	Confidence	Extractor
https://developers.openai.com/api/docs/models/gpt-5.1-codex-max	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Descriptiondescription1

Claim history for Description
Value	Valid from → to	Status	Source	Confidence	Extractor
A version of GPT-5.1-codex optimized for long running tasks.	11 Sept 2026 20:51 UTC → current	current	OpenAI Platform docsT1	high	deterministic

Openrouter idopenrouter_id1

Claim history for Openrouter id
Value	Valid from → to	Status	Source	Confidence	Extractor
openai/gpt-5.1-codex-max	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Reasoningreasoning1

Claim history for Reasoning
Value	Valid from → to	Status	Source	Confidence	Extractor
Yes	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Structured outputstructured_output1

Claim history for Structured output
Value	Valid from → to	Status	Source	Confidence	Extractor
Yes	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Supported parameterssupported_parameters1

Claim history for Supported parameters
Value	Valid from → to	Status	Source	Confidence	Extractor
include_reasoning, max_completion_tokens, reasoning, reasoning_effort, response_format, seed, structured_outputs, tool_choice, tools	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Tool callingtool_calling1

Claim history for Tool calling
Value	Valid from → to	Status	Source	Confidence	Extractor
Yes	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Visionvision1

Claim history for Vision
Value	Valid from → to	Status	Source	Confidence	Extractor
Yes	11 Sept 2026 21:10 UTC → current	current	OpenRouter public model & pricing listingT2	medium	deterministic

Claims are temporal and append-only: a new observation closes the previous claim (valid_to) instead of overwriting it. Conflicting claims from different sources are kept side by side and flagged — never averaged. Methodology →

Provenance

Attributed facts

21

Source tiers

T1T28 / 13

Freshest observation

13 h ago

Conflicts

None

Source documents 3

Source documents
Source	Document	Type	Tier	Last observed	Snapshots
OpenAI Platform docs	developers.openai.com/api/docs/deprecations.md	model_docs	T1· Official	13 h ago	1
OpenAI Platform docs	developers.openai.com/api/docs/models.md	model_docs	T1· Official	13 h ago	1
OpenRouter public model & pricing listing	openrouter.ai/api/v1/models	catalogue	T2· Quality secondary	13 h ago	1

Tier 1 = official/primary, 2 = quality secondary, 3 = community, 4 = unverified. Every snapshot is archived; see all sources and the methodology.

Data quality (69/100) measures how well AI Atlas knows this entity — completeness, primary-source ratio, freshness, conflicts — never how good the model is. Methodology →