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AI model reference · 2026

Claude Opus 4.5

Anthropic: Claude Opus 4.5 logoAnthropicModel details, evidence, and API facts

Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use.

Text generation
Image input
Reasoning
Provider endpoint accepts tool parameters
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Context window
200,000 tokens
Maximum output
64,000 tokens
Base provider API input
$5.00 / 1M tokens
Base provider API rate
Published evidence
3 benchmarks, 0 Arena results

Overview

About Claude Opus 4.5

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

Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use.

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 4.5
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.76.8%ResolvedVersion: SWE-Bench Verified 500 · Split: Verified, 500 tasks · Harness: mini-SWE-agent / version 2.0.0 · Attempts: One attempt · Reasoning effort: highProtocol note: Harness version: 2.0.0; Run date: 2026-02-17Methodology SWE-benchBenchmark owner
LiveBenchA contamination-resistant benchmark refreshed on a fixed release cadence. Scores from different LiveBench releases must never be compared as the same protocol.72.6%Mean of category averagesVersion: LiveBench 2026-06-25 · Split: 2026-06-25 release, 23 tasks across seven categories · Reasoning effort: highProtocol note: Overall is the mean of category averages. This protocol is not comparable with the 2026-01-08 release.Methodology LiveBenchBenchmark owner
Vending-Bench 2Tests AI models ability to manage a simulated vending machine business over a year4,967.06Money 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.

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
Nov 24, 2025
Context window
200,000 tokens
Maximum output
64,000 tokens
Knowledge cutoff
Not available in reviewed sources
License
Not available in reviewed sources
Capabilities and API
Input types
File, Image, Text
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 Nov 24, 2025.

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

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