How many parameters does GPT-5.1-Codex-Max have?

Parameter count for GPT-5.1-Codex-Max is not available. See the Hugging Face model page for full specifications.

Who created GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max was published by OpenAI on Hugging Face.

GPT-5.1-Codex-Max

Name: GPT-5.1-Codex-Max
Author: OpenAI

Multimodalby OpenAI·Model page ↗

OpenAI's advanced reasoning coding model with multimodal input and a 400K-token context.

Max output

Most tokens the model can return in a single response.

128Ktokens

Reasoning

Reasoning-first model

Works through a step-by-step chain of thought before answering.

Pricing

per 1M tokens

Input$1.25 /1M

Output$10 /1M

Cache read$0.125 /1M

Web search$0.01

Model Description

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...

Author

OpenAI

Organization · ✓

openai

Details

Downloads—

Likes—

AccessClosed Source

Context400K tokens

Input price$1.25 /1M

Output price$10 /1M

CreatedDec 4, 2025

Updated—

View on Hugging Face

Get the full context.