# GPT-5.1 Codex Max

> GPT-5.1 Codex Max is a maximum-effort variant of GPT-5.1 Codex optimized for long-horizon agentic coding inside the Codex environment, with extended context and reasoning support. Served through OpenAI's Codex surfaces.


**ID**: `openai/gpt-5.1-codex-max`  
**Creator**: OpenAI  
**Category**: text  
**Context**: 400K tokens  
**Input**: $2.50/M  
**Output**: $20.00/M  
**Released**: 2025-12-04  
**Web page**: https://anyrouter.dev/model/openai/gpt-5.1-codex-max

**Input modalities**: text, image  
**Output modalities**: text  

**Tokenizer**: GPT

**Capabilities**: chat, coding, reasoning, streaming, function-calling, vision

## Providers

| Provider | Input | Output |
| --- | --- | --- |
| opencode-zen-byok | $2.50/M | $20.00/M |

## Benchmarks

- **GPQA Diamond**: 0.9