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AI model reference · 2026

gpt-oss-120b

OpenAI: gpt-oss-120b logoOpenAIModel details, evidence, and API facts

gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases.

Text generation
Reasoning
Provider endpoint accepts tool parameters
Context window
131,072 tokens
Maximum output
131,072 tokens
Base provider API input
$0.037 / 1M tokens
Base provider API rate
Published evidence
1 benchmark, 1 Arena result

Overview

About gpt-oss-120b

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

gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases.

text
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-oss-120b
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.26.0%ResolvedVersion: SWE-Bench Verified 500 · Split: Verified, 500 tasks · Harness: mini-SWE-agent / version 1.7.0 · Attempts: One attemptProtocol note: Harness version: 1.7.0; Run date: 2025-08-07Methodology SWE-benchBenchmark owner

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-oss-120b
CategoryScoreRankVotesStatus
Arena TextBlind human preference score for text responses.1,352±4#19630,761Published

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
Aug 5, 2025
Context window
131,072 tokens
Maximum output
131,072 tokens
Knowledge cutoff
2024-06-30
License
Not available in reviewed sources
Capabilities and API
Input types
Text
Output types
Text
Reasoning
Supported
Provider endpoint tool parameters
Accepts tool parameters
Base provider API input
$0.037 / 1M tokens
Base provider cached input
Not available
Base provider API output
$0.17 / 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 25, 2026.

Catalog record updated Aug 5, 2025.

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

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