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Claude Sonnet 4.5 Thinking

claude-sonnet-4-5-20250929-thinking
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Claude Sonnet 4.5 Thinking

claude-sonnet-4-5-20250929-thinking

Adds extended, step‑by‑step reasoning for tougher coding, planning, and multi‑tool tasks. Ideal for long‑horizon agent workflows, complex problem solving, and scenarios that benefit from explicit thinking traces.

Added Sep 29, 2025

Context Window

1.0M

Max Output

64.0K

Avg output tokens (7d)

1.7K tokens

66%

Input Price (Auto)

$3.00/1M

Output Price (Auto)

$15.00/1M

Cache Read (Auto)

$0.30/1M

Capabilities

Benchmarks

Performance metrics and benchmarks

Sourced from Artificial Analysis.

Intelligence Index

37.4

Better than 80% of models compared

Coding Index

52.1

Better than 67% of models compared

Agentic Index

26.4

Better than 59% of models compared

Reasoning

GPQA Diamond

Graduate-level scientific reasoning

83.4%

Better than 76% of models compared

HLE

Humanity's Last Exam

17.8%

Better than 72% of models compared

IFBench

Instruction-following benchmark

57.3%

Better than 68% of models compared

T²-Bench Telecom

Conversational AI agents in dual-control scenarios

78.1%

Better than 68% of models compared

AA-LCR

Long context reasoning evaluation

68.3%

Better than 76% of models compared

Coding

SciCode

Python programming for scientific computing

44.7%

Better than 83% of models compared

Terminal-Bench Hard

Agentic coding and terminal use

35.6%

Better than 82% of models compared

LiveCodeBench

Contamination-free coding benchmark

71.4%

Better than 82% of models compared

Math

AIME 2025

American Invitational Mathematics Examination 2025

88.0%

Better than 86% of models compared

Knowledge

MMLU-Pro

Professional and academic subject knowledge

87.5%

Better than 98% of models compared

Last updated Aug 16, 2026

Artificial Analysis

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