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AI Atlas
ModelRetiredProprietary

GPT-5.1-Codex

OpenAIdevelopers.openai.com/api/docs/models/gpt-5.1-co

A version of GPT-5.1 optimized for agentic coding in Codex.

quality72

Updated 10 min ago · first seen 11 Sept 2026

model_01M293VC59AGHGMC4F9791V5E1

Context
400K tokens
T2 · 10 min ago
Released
13 Nov 2025
T2 · 10 min ago

Specification

Release date
13 Nov 2025

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Status
retired

Source:OpenAI Platform docsT1observed 28 min agohigh

Openness
proprietary

Source:OpenAI Platform docsT1observed 28 min agohigh

Context window
400K tokens

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Max output
128K tokens

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Modalities
image, text

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Input modalities
image, text

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Output modalities
text

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Tokenizer
GPT

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

API model id
gpt-5.1-codex

Source:OpenAI Platform docsT1observed 28 min agohigh

Deprecation date
22 Apr 2026

Source:OpenAI Platform docsT1observed 28 min agohigh

Retirement date
23 Jul 2026

Source:OpenAI Platform docsT1observed 28 min agohigh

Retirement tentative
No

Source:OpenAI Platform docsT1observed 28 min agohigh

Official page

Source:OpenAI Platform docsT1observed 28 min agohigh

Openrouter id
openai/gpt-5.1-codex

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Supported parameters
include_reasoning, max_completion_tokens, reasoning, reasoning_effort, response_format, seed, structured_outputs, tool_choice, tools

Source:OpenRouter public model & pricing listingT2observed 10 min agomedium

Each value shows its source, tier and observation time. Conflicting claims are kept side by side and flagged — never averaged. How AI Atlas records facts →

Provenance

Attributed facts

21

Source tiers

T1T28 / 13

Freshest observation

10 min ago

Conflicts

None