# GPT-5.1

> OpenAI's reasoning model for coding and agentic tasks, with configurable reasoning effort, listed by OpenAI as deprecated.

## Key facts

- Model author: OpenAI
- Input: $1.25 per 1M tokens
- Output: $10.00 per 1M tokens
- Cached input: $0.125 per 1M tokens
- Context window: 400,000 tokens
- Maximum output: 128,000 tokens
- Input modalities: image, text
- Output modalities: text
- Capabilities: reasoning, structured_output, tools, vision
- Released: 2025-11-13
- Knowledge cutoff: Sep 30, 2024
- Model IDs: `openai/gpt-5.1`
- Model page: https://www.realrelay.ai/model/openai/gpt-5.1

## Overview

GPT-5.1 is a reasoning model from OpenAI for coding and agentic tasks, with configurable reasoning effort. It accepts text and image input, returns text, and supports tool calling and structured output. OpenAI lists it as deprecated, so plan a migration path for any long-lived workload.

It has a 400K-token context window and can generate up to 128,000 output tokens. It accepts text and image input and returns text. Its knowledge cutoff is September 30, 2024, and it was released on November 13, 2025.

## Capabilities

GPT-5.1 supports reasoning, tool calling, structured output and image input, and returns text output.

OpenAI documents GPT-5.1 for coding and agentic tasks with configurable reasoning effort.

## Pricing

GPT-5.1 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. Cached input reads cost $0.125 per 1M tokens. GPT-5.1 is available through RealRelay's OpenAI-compatible API.

## Use cases

Use GPT-5.1 to keep existing coding agents running: it reads code, calls tools and returns structured output within a 400K-token context window.

It also handles agentic tasks that pair tool calls with image input, such as inspecting a screenshot of an error before proposing a fix. Its configurable reasoning effort lets teams adjust how much reasoning a task receives.

## Call it

OpenAI-compatible chat completions:

```bash
curl https://www.realrelay.ai/v1/chat/completions \
  -H "Authorization: Bearer $REALRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "openai/gpt-5.1", "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

### What is GPT-5.1?

GPT-5.1 is a reasoning model from OpenAI for coding and agentic tasks, with configurable reasoning effort.

### How much does GPT-5.1 cost?

GPT-5.1 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. Cached input reads cost $0.125 per 1M tokens.

### What is the context window of GPT-5.1?

GPT-5.1 has a 400K-token context window and can generate up to 128,000 output tokens.

### What inputs and outputs does GPT-5.1 support?

GPT-5.1 accepts text and image input and returns text.

### Does GPT-5.1 support tool calling?

Yes. GPT-5.1 supports tool calling, along with reasoning, structured output and image input.

### When was GPT-5.1 released?

GPT-5.1 was released on November 13, 2025. Its knowledge cutoff is September 30, 2024.

### How do I call GPT-5.1 via the API?

Call GPT-5.1 through RealRelay's OpenAI-compatible API by setting the model name to openai/gpt-5.1.