Claude Opus 4.5

Summary

Claude Opus 4.5 is Anthropic's most capable model at the time of its November 2025 release — the first AI model to break the 80% threshold on SWE-bench Verified, scoring 80.9% on one of the field's most demanding real-world coding benchmarks.

Overview

Claude Opus 4.5 is Anthropic's most capable model at the time of its November 2025 release — the first AI model to break the 80% threshold on SWE-bench Verified, scoring 80.9% on one of the field's most demanding real-world coding benchmarks. It represents Anthropic's best at complex reasoning, deep analysis, nuanced writing, and the most demanding agentic tasks. Notably, Anthropic cut its price by roughly 67% compared to the previous Opus generation, bringing frontier-class capability closer to production accessibility.

Opus 4.5 is the right choice when maximum capability matters more than cost or speed: hard research problems, complex multi-step reasoning chains, code that requires careful architectural judgment, and tasks where errors are expensive. It is the model Anthropic positions at the top of the intelligence hierarchy — though as of February 2026, it has been joined by Opus 4.6 which adds 1M context support and further coding improvements.

Specifications

  • Developer: Anthropic
  • Model String: claude-opus-4-5-20251101
  • Release Date: November 2025
  • Type: Large Language Model (LLM), Multimodal (text + vision)
  • Context Window: 200,000 tokens (1M tokens available via context-1m-2025-08-07 beta header)
  • Max Output: 8,192 tokens
  • Access: Anthropic API, Amazon Bedrock, Google Cloud Vertex AI, Claude.ai Pro/Team/Enterprise
  • Pricing: $5 per million input tokens / $25 per million output tokens (~67% price reduction vs. Claude 3 Opus)

Capabilities

Coding: Industry-leading 80.9% on SWE-bench Verified at launch — the first model to break the 80% barrier. Handles architectural decisions, large-scale refactoring, and complex debugging that challenge smaller models.

Reasoning: Best-in-class for multi-step logical reasoning, graduate-level problem solving, and tasks requiring sustained analytical depth across long contexts.

Writing & Analysis: Excels at nuanced long-form writing, research synthesis, complex document analysis, and tasks requiring careful judgment about tone, structure, and accuracy.

Agentic Capability: Strong performance in long-horizon autonomous tasks. Can handle the most complex orchestration scenarios where Sonnet would struggle.

Vision: Full multimodal capability including chart analysis, document processing, and visual reasoning.

Limitations

At $5/$25 per million tokens, Opus 4.5 is approximately 5x more expensive than Haiku 4.5, making it unsuitable for high-volume or latency-sensitive applications. For most production use cases, Sonnet 4.5 or 4.6 delivers excellent results at lower cost. Opus is the specialist for genuinely hard problems — using it for routine tasks is overkill.

Recent Developments

  • November 2025 Launch: First model to exceed 80% on SWE-bench Verified (80.9%), setting a new industry benchmark for AI coding capability.
  • Significant Price Drop: Priced at $5/$25 per million tokens — roughly 67% cheaper than Claude 3 Opus — making frontier-tier intelligence more commercially viable.
  • Joined by Opus 4.6: In February 2026, Anthropic released Opus 4.6 with 1M context support and further improvements to coding and workplace tasks. Opus 4.5 remains available for developers on existing integrations.

Last Updated

February 26, 2026

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