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AI model reference · 2026

GPT-5.1

OpenAI: GPT-5.1 logoOpenAIModel details, evidence, and API facts

GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5.

Text generation
Image input
Reasoning
Provider endpoint accepts tool parameters
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Context window
400,000 tokens
Maximum output
128,000 tokens
Base provider API input
$1.25 / 1M tokens
Base provider API rate
Published evidence
2 benchmarks, 2 Arena results

Overview

About GPT-5.1

A concise catalog overview. Technical limits and published evaluation evidence are listed separately below.

GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5.

text
multimodal
reasoning

Published evaluations

Benchmark results

Only results mapped to this exact model and backed by a named source appear here. Different evaluation protocols are not treated as interchangeable.

Source-backed benchmark results for GPT-5.1
BenchmarkScoreEvaluation detailsSource
SWE-Bench VerifiedA human-validated subset of real GitHub issues used to measure whether a coding agent can produce repository patches that resolve the associated tests.66.0%ResolvedVersion: SWE-Bench Verified 500 · Split: Verified, 500 tasks · Harness: mini-SWE-agent / version 1.15.0 · Attempts: One attempt · Reasoning effort: mediumProtocol note: Harness version: 1.15.0; Run date: 2025-11-20Methodology SWE-benchBenchmark owner
Vending-Bench 2Tests AI models ability to manage a simulated vending machine business over a year1,473.43Money Balance ($)The published protocol is not fully disclosed.Methodology andonlabs.comLegacy leaderboard

Human preference

Arena results

Arena scores come from blind human preference votes. They are reported separately from task benchmarks and are not used as substitutes for missing benchmark results.

Arena results for GPT-5.1
CategoryScoreRankVotesStatus
Arena TextBlind human preference score for text responses.1,439±4#7743,666Published
Arena WebDevBlind human preference score for code and web development.1,341±9#8410,350Published

Technical reference

Specifications and API facts

Technical limits and reference provider prices come from the current catalog unless a reviewed external source is listed. Missing values stay marked as unavailable.

Model
Provider
OpenAI
Release date
Not available in reviewed sources
Catalog added
Nov 13, 2025
Context window
400,000 tokens
Maximum output
128,000 tokens
Knowledge cutoff
Not available in reviewed sources
License
Not available in reviewed sources
Capabilities and API
Input types
Image, Text, File
Output types
Text
Reasoning
Supported
Provider endpoint tool parameters
Accepts tool parameters
Base provider API input
$1.25 / 1M tokens
Base provider cached input
$0.125 / 1M tokens
Base provider API output
$10 / 1M tokens

These are reference provider API rates, not Writingmate checkout charges. Access in Writingmate follows the allowances of your Writingmate plan.

Provenance

Sources and update status

Source links are attached to the facts and evaluations they support. Catalog-only values are not presented as independently verified claims.

Evidence last updated Aug 12, 2026.

Catalog record updated Nov 13, 2025.

Catalog-added dates describe when a model entered the catalog, not necessarily its public release date.

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