GPT 5.1

OpenAI
openai/gpt-5.1

Improved reasoning, longer context

Context Window

272K

272,000 tokens

Max Output

128K

128,000 tokens

About this model

GPT-5.1 further optimizes reasoning capabilities and context processing efficiency over GPT-5. It maintains the 272K context window while being more reliable in instruction following, structured output, and tool calling.

For programming tasks, GPT-5.1 shows notable improvements in code generation quality and bug fixing compared to GPT-5, especially in understanding and modifying large codebases.

Highlights

272K context window
Stronger instruction following
Enhanced code ability
More reliable tool calling

Best For

Code review & refactoringComplex instruction executionStructured data processing
2026-01-15TransformerProprietary

Capabilities

ChatVisionReasoningCodepdftoolscache

Aliases

gpt-5.1
gpt
gpt-latest
chatgpt
gpt-5-latest

Pricing (per 1M tokens)

Pricing (per 1M tokens)/ 1M tokens
Input / 1M$1.31
Output / 1M$10.50
Cache Read$0.13

Final prices shown

Quick Start

main.py
from openai import OpenAI

client = OpenAI(
    base_url="https://api.chuizi.ai/v1",
    api_key="ck-your-key-here",
)

response = client.chat.completions.create(
    model="openai/gpt-5.1",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)

FAQ

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