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ModelRetiredClosed / proprietaryIdentity probable

GPT-5.1-Codex-Max

OpenAIfamily · GPT 5.1developers.openai.com/api/docs/models/gpt-5.1-co

A version of GPT-5.1-codex optimized for long running tasks.

Open in Graph
data quality72

Updated 5 h ago · first seen 11 Sept 2026

model_01M293VC5D6R1T4YX4QXP13HX6

Overview

Identity

Canonical model
Yesidentity confidence: mediumOne row per real model release. Artifacts (checkpoints, quantisations, conversions) and folded evaluation variants point here.
Official checkpoints
None recorded — closed weightsofficial_checkpoints = hf_repo identifiers carried by the model itself; artifacts are separate entities pointing here through canonical_id.
Artifacts
None recordedSeparate entities (checkpoint · quantization · conversion · packaging) pointing to this model through canonical_id.
Provider deployments
2
API aliases
gpt-5.1-codex-maxopenai/gpt-5.1-codex-maxIdentifiers under which providers and evaluators refer to this model.
Folded evaluation variants
0Effort / thinking variants (…-high, …-non-reasoning) are result configurations of this model, not separate models. Their old URLs redirect here.

Openness

Closed / proprietary— weights not available; 7 dimensions unknown.

Weights are not available; the model is reachable only through an API or a product.

  • Weights

    No

  • Inference code

    —

  • Training code

    —

  • Training data

    —

  • Dataset

    —

  • Commercial use

    —

  • Redistribution

    —

  • Derivatives

    —

dimensions marked null are unknown, not false

Key facts

Release date

Source:OpenRouter public model & pricing listingT2observed 15 h agomedium

Status

Source:OpenAI Platform docsT1observed 15 h agohigh

Deprecation date

Source:OpenAI Platform docsT1observed 15 h agohigh

Retirement date

Source:OpenAI Platform docsT1observed 15 h agohigh

Official page
developers.openai.com/api/docs/models/gpt-5.1-codex-max

Source:OpenAI Platform docsT1observed 15 h agohigh

API model id

Source:OpenAI Platform docsT1observed 15 h agohigh

Openrouter id

Source:OpenRouter public model & pricing listingT2observed 15 h agomedium

Architecture

Tokenizer

Source:OpenRouter public model & pricing listingT2observed 15 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 15 h agomedium

Max output

Source:OpenRouter public model & pricing listingT2observed 15 h agomedium

Tokenizer

Source:OpenRouter public model & pricing listingT2observed 15 h agomedium

Providers & Pricing2

All offers in the price terminal →
Provider deployments, cheapest output first
ProviderContextInput / 1MCached inOutput / 1MStatusObservedSource
OpenAI APIcheapest outputopenai/gpt-5.1-codex-max400Kout 128K$0.125active6 h agosince 11 Sept 2026openrouter.aiT2
OpenRouteropenai/gpt-5.1-codex-max400Kout 128K$0.125active3 h agosince 12 Sept 2026openrouter.aiT2

USD per 1M tokens as published by each provider; native units (per-request fees, flex/priority tiers) are kept verbatim. Rows are append-only — every price change is kept in the history below. Cost of a workload →

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 2 providers

Output price history of GPT-5.1-Codex-Max$0$2$4$6$8$10$12Sept 26Sept 26Sept 26Sept 26OpenAI API: first observed → $10 · 11 Sept 2026OpenRouter: first observed → $10 · 12 Sept 2026
  • OpenAI API
  • OpenRouter
  • OpenRouterfirst observed $1012 Sept 2026
  • OpenAI APIfirst observed $1011 Sept 2026

Input price · USD / 1M tokens 2 providers

Input price history of GPT-5.1-Codex-Max$0$0.50$1$1.5Sept 26Sept 26Sept 26Sept 26OpenAI API: first observed → $1.25 · 11 Sept 2026OpenRouter: first observed → $1.25 · 12 Sept 2026
  • OpenAI API
  • OpenRouter
  • OpenRouterfirst observed $1.2512 Sept 2026
  • OpenAI APIfirst observed $1.2511 Sept 2026

Versions & Artifacts0

Version history

Context windowfirst observation only

11 Sept 2026current

Max outputfirst observation only

11 Sept 2026current

Opennessfirst observation only

11 Sept 2026current

Statusfirst observation only

11 Sept 2026current

Each hop is a claim: click a value for its source, tier and observation time. Nothing is overwritten — a new observation closes the previous claim.

Artifacts 0

No artifact (checkpoint, quantisation, conversion or packaging) points to this model yet.

Timeline1

Full timeline →

Change history23

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 1 Jul 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 1 Jul 2026

First seen 11 Sept 2026. Nothing is inferred backwards: no attribute is shown for dates before the first observation.
23 claims · 23 properties

Release daterelease_date1

Claim history for Release date
ValueValid from → toStatusSourceConfidenceExtractor
4 Dec 2025 → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Statusstatus1

Claim history for Status
ValueValid from → toStatusSourceConfidenceExtractor
retired → currentcurrentOpenAI Platform docsT1highdeterministic

Opennessopenness1

Claim history for Openness
ValueValid from → toStatusSourceConfidenceExtractor
proprietary → currentcurrentOpenAI Platform docsT1highdeterministic

Context windowcontext_length1

Claim history for Context window
ValueValid from → toStatusSourceConfidenceExtractor
400K tokens → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Max outputmax_output_tokens1

Claim history for Max output
ValueValid from → toStatusSourceConfidenceExtractor
128K tokens → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Modalitiesmodalities1

Claim history for Modalities
ValueValid from → toStatusSourceConfidenceExtractor
image, text → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Input modalitiesmodalities_input1

Claim history for Input modalities
ValueValid from → toStatusSourceConfidenceExtractor
image, text → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Output modalitiesmodalities_output1

Claim history for Output modalities
ValueValid from → toStatusSourceConfidenceExtractor
text → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Tokenizertokenizer1

Claim history for Tokenizer
ValueValid from → toStatusSourceConfidenceExtractor
GPT → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

API model idapi_model_id1

Claim history for API model id
ValueValid from → toStatusSourceConfidenceExtractor
gpt-5.1-codex-max → currentcurrentOpenAI Platform docsT1highdeterministic

Deprecation datedeprecation_date1

Claim history for Deprecation date
ValueValid from → toStatusSourceConfidenceExtractor
22 Apr 2026 → currentcurrentOpenAI Platform docsT1highdeterministic

Retirement dateretirement_date1

Claim history for Retirement date
ValueValid from → toStatusSourceConfidenceExtractor
23 Jul 2026 → currentcurrentOpenAI Platform docsT1highdeterministic

Retirement tentativeretirement_tentative1

Claim history for Retirement tentative
ValueValid from → toStatusSourceConfidenceExtractor
No → currentcurrentOpenAI Platform docsT1highdeterministic

Official pageofficial_url1

Claim history for Official page
ValueValid from → toStatusSourceConfidenceExtractor
https://developers.openai.com/api/docs/models/gpt-5.1-codex-max → currentcurrentOpenAI Platform docsT1highdeterministic

Descriptiondescription1

Claim history for Description
ValueValid from → toStatusSourceConfidenceExtractor
A version of GPT-5.1-codex optimized for long running tasks. → currentcurrentOpenAI Platform docsT1highdeterministic

Openrouter idopenrouter_id1

Claim history for Openrouter id
ValueValid from → toStatusSourceConfidenceExtractor
openai/gpt-5.1-codex-max → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Openrouter listed atopenrouter_listed_at1

Claim history for Openrouter listed at
ValueValid from → toStatusSourceConfidenceExtractor
4 Dec 2025 → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Reasoningreasoning1

Claim history for Reasoning
ValueValid from → toStatusSourceConfidenceExtractor
Yes → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Structured outputstructured_output1

Claim history for Structured output
ValueValid from → toStatusSourceConfidenceExtractor
Yes → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Supported parameterssupported_parameters1

Claim history for Supported parameters
ValueValid from → toStatusSourceConfidenceExtractor
include_reasoning, max_completion_tokens, reasoning, reasoning_effort, response_format, seed, structured_outputs, tool_choice, tools → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Tool callingtool_calling1

Claim history for Tool calling
ValueValid from → toStatusSourceConfidenceExtractor
Yes → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Visionvision1

Claim history for Vision
ValueValid from → toStatusSourceConfidenceExtractor
Yes → currentcurrentOpenRouter public model & pricing listingT2mediumdeterministic

Weights availableweights_available1

Claim history for Weights available
ValueValid from → toStatusSourceConfidenceExtractor
No → currentcurrentAI Atlas curated registry (YAML, versioned in git, every entry carries its source URL)T2highderived

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

24

Source tiers

T1T28 / 16

Freshest observation

5 h ago

Conflicts

None

Source documents 3

Source documents
SourceDocumentTypeTierLast observedSnapshots
OpenAI Platform docsdevelopers.openai.com/api/docs/deprecations.md model_docsT1· Official3 h ago2
OpenAI Platform docsdevelopers.openai.com/api/docs/models.md model_docsT1· Official3 h ago1
OpenRouter public model & pricing listingopenrouter.ai/api/v1/models catalogueT2· Quality secondary3 h ago10

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

Data quality (72/100) measures how well AI Atlas knows this entity — completeness, primary-source ratio, freshness, conflicts — never how good the model is. Methodology →