What is OpenAI: GPT-5.1 Codex Max's context window?

OpenAI: GPT-5.1 Codex Max supports a context window of 256,000 tokens, allowing you to process large documents and maintain long conversations.

How to use OpenAI: GPT-5.1 Codex Max API via Ofox?

Simply set your base URL to https://api.ofox.io/v1 and use your Ofox API key. The API is OpenAI-compatible — just change the base URL and API key in your existing code.

OpenAI: GPT-5.1 Codex Max

Name: OpenAI: GPT-5.1 Codex Max
Brand: openai
Price: 1.25 USD
Availability: InStock

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openai/gpt-5.1-codex-max

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GPT-5.1 Codex Max is OpenAI's agentic coding model, released on 2025-12-04 and 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 workflows spanning software engineering, mathematics, and research. Capabilities include reasoning, tool use, prompt caching, web search, and multimodal input covering images, audio, and video. Context window: 256K tokens, output: 128K. Prompt caching keeps long agent sessions that reuse the same repository context affordable. Accessible via the OpenAI-compatible protocol through Ofox.

Context Window

256K

Max Output Tokens

128K

Released

2025-12-04

Capabilities

VisionFunction CallingReasoningPrompt CachingWeb SearchAudio InputVideo Input

Available Providers

Azure

Supported Protocols

openai

Providers

Azure

Input Tokens

$1.25/M

Output Tokens

$10/M

Cache Read

$0.13/M

Web Search

$0.035/R

Protocols

openai/v1/chat/completions/v1/responses

Code Examples

from openai import OpenAI

client = OpenAI(
    base_url="https://api.ofox.io/v1",
    api_key="YOUR_OFOX_API_KEY",
)

response = client.chat.completions.create(
    model="openai/gpt-5.1-codex-max",
    messages=[
        {"role": "user", "content": "Hello!"}
    ],
)

print(response.choices[0].message.content)