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AI model reference · 2026

Claude Opus 5

Claude Opus 5 logoAnthropicModel details, evidence, and API facts

Claude Opus 5 is Anthropic’s flagship model for demanding reasoning, coding, and long-horizon agentic work.

Text generation
Image input
Reasoning
Provider endpoint accepts tool parameters
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Context window
1,000,000 tokens
Maximum output
128,000 tokens
Base provider API input
$5.00 / 1M tokens
Base provider API rate
Published evidence
5 benchmarks, 0 Arena results

Overview

About Claude Opus 5

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

Claude Opus 5 is Anthropic’s flagship model for demanding reasoning, coding, and long-horizon agentic work.

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 Claude Opus 5
BenchmarkScoreEvaluation detailsSource
OSWorld-VerifiedA verified computer-use benchmark in which multimodal agents operate desktop applications and are graded from the resulting environment state.83.4%Mean task rewardVersion: OSWorld-Verified v1 · Split: Up to 361 tasks, excluding eight Google Drive tasks where required · Harness: Official OSWorld unified environment · Attempts: One run · Tools: GUI interactionProtocol note: Only 100-step general-model rows are included in this normalized snapshot. Individual evaluated-task counts can differ when a task could not run.; Run date: 2026-07-31; Evaluated tasks: 360Methodology OSWorldBenchmark owner
DeepSWE 1.1A long-horizon software-engineering benchmark with 113 original tasks graded by hand-written tests.74.0%±4Pass@1Version: DeepSWE 1.1 · Split: 113 tasks across 91 repositories · Harness: mini-swe-agent · Reasoning effort: maxProtocol note: All models use the same harness. Cost, output-token, and step counts are retained per result as protocol context.; Confidence interval: ±4Methodology DataCurveBenchmark owner
GPQA DiamondThe highest-quality subset of Graduate-Level Google-Proof Q&A, designed to test expert-level scientific reasoning in biology, physics, and chemistry.93.2%AccuracyVersion: GPQA Diamond 198 · Split: 198 Diamond questions · Harness: Artificial Analysis independent evaluation · Tools: Not disclosed on the score page · Reasoning effort: maxMethodology Artificial AnalysisIndependently reproduced
Humanity's Last ExamA 2,500-question expert-level benchmark spanning dozens of academic fields. Tool-assisted and no-tools results are separate protocols and must not be merged.54.9%AccuracyVersion: May 2025 text-only revision · Split: 2,158 text-only questions from the 2,500-question May 2025 revision · Attempts: pass@1 · Tools: No browser or retrieval tools · Evaluator: LLM equality checker with numerical tolerance · Reasoning effort: maxMethodology Artificial AnalysisIndependently reproduced
LiveBenchA contamination-resistant benchmark refreshed on a fixed release cadence. Scores from different LiveBench releases must never be compared as the same protocol.80.1%Mean of category averagesVersion: LiveBench 2026-06-25 · Split: 2026-06-25 release, 23 tasks across seven categories · Reasoning effort: maxProtocol note: Overall is the mean of category averages. This protocol is not comparable with the 2026-01-08 release.Methodology LiveBenchBenchmark 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.

No exact Arena match is available for this model. Similar names and provider variants are not merged automatically.

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
Anthropic
Release date
Not available in reviewed sources
Catalog added
Jul 24, 2026
Context window
1,000,000 tokens
Maximum output
128,000 tokens
Knowledge cutoff
Not available in reviewed sources
License
Not available in reviewed sources
Capabilities and API
Input types
Text, Image, File
Output types
Text
Reasoning
Supported
Provider endpoint tool parameters
Accepts tool parameters
Base provider API input
$5.00 / 1M tokens
Base provider cached input
$0.50 / 1M tokens
Base provider API output
$25 / 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 9, 2026.

Catalog record updated Jul 24, 2026.

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

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