GPT-5.1-Codex-Max — OpenAI | Modeldex

GPT-5.1-Codex-Max

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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...

VisionLong context

API release

Dec 4, 2025(4 months ago)

Not enough benchmark coverage yet for an Intelligence Index — needs at least 3 results across 2 categories.

Overview

History

GPT-5.1-Codex-Max became available via the OpenAI API on 2025-12-04.

Training & availability

OpenAI has not released the underlying model weights — access is via their hosted API only.

Capabilities

Context window: 400K tokens.
Input modalities: text, image.

Recommended for: vision, long-context.

Pricing

Input: $1.2500 per 1M tokens
Output: $10.0000 per 1M tokens

Use the cost calculator above to estimate monthly spend for your workload.

Quick start

Minimal example using the openai API. Copy, paste, replace the key.

from openai import OpenAI

client = OpenAI(api_key="sk-...")
resp = client.chat.completions.create(
    model="gpt-5-1-codex-max",
    messages=[{"role": "user", "content": "Explain quantum computing in one sentence."}],
)
print(resp.choices[0].message.content)

Cost calculator

Estimate your monthly bill. Presets are typical workload sizes.

Input tokens / month5.0M

@ $1.25/1M

Output tokens / month2.0M

@ $10/1M

Input cost

$6.25

5.0M × $1.25/1M

Output cost

$20

2.0M × $10/1M

Total / month

$26.25

$315 / year

Integrations & tooling support

Tool calling: Not supported
Structured outputs: Not supported

Price vs quality

Not enough data

This model has no benchmark scores recorded yet.

Community ratings

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