# Claude Opus 5.5

Anthropic, released 2026-09-22

**Verdict: conditional.** Claude Opus 5.5 is the model Anthropic now recommends starting with for most workloads, built for long-running agentic coding and knowledge work at rates 20% below Claude Opus 5. Conditional because every benchmark is Anthropic's own and migration is not drop-in: thinking cannot be turned off, forced tool use returns an error, and most cybersecurity tasks are rerouted to Opus 4.8. Right for Claude Opus 5 teams that can absorb those breaking changes. Last verified 2026-10-02.

## Pricing

- Input: $4 / 1M tokens
- Output: $20 / 1M tokens
- Context: 1M ctx; 128K out; cache $0.20; fast $8/$40

## Strengths

- Long-running agentic coding and knowledge work, the use Anthropic built it for, with a 1M-token context and 128K output (300K on the Batch API in beta)
- Cutting cost from Claude Opus 5: $4/$20 per 1M tokens against $5/$25, cache reads $0.20 against $0.50, batch $2/$10
- Cache-heavy agent loops: cache hits cost 5% of the input price, half the standard 10% ratio
- Latency-sensitive work on the Claude API: fast mode (research preview) runs $8/$40 per 1M tokens, below Opus 5's $10/$50 fast rate
- Drop-in upgrades from Opus 5: thinking cannot be disabled, forced tool use returns an error, thinking blocks are tied to the model and conversation, and computer_20251124 is refused on the Claude API and Google Cloud
- Apps that stream progress text between tool calls: that text now returns in thinking blocks that are empty at the default display setting
- Cybersecurity work: Anthropic says most cyber tasks are rerouted to Opus 4.8, and its Cyber Verification Program has not yet been expanded to include Opus 5.5
- Decisions that need independent benchmarks: every published score is Anthropic's own

## Benchmarks

- Terminal-Bench 4.0 (Anthropic-reported, max effort): 66.4% (https://www.anthropic.com/claude-opus-5-5)
- FrontierCode v1.1 Main (Anthropic-reported, max effort): 54.4% (https://www.anthropic.com/claude-opus-5-5)
- CursorBench 4.0 (Anthropic-reported, max effort): 57.8% (https://www.anthropic.com/claude-opus-5-5)
- GDPval-AA v2.1 (Anthropic-reported, max effort): 1846 Elo (https://www.anthropic.com/claude-opus-5-5)
- Humanity's Last Exam, with tools (Anthropic-reported, max effort): 67.7% (https://www.anthropic.com/claude-opus-5-5)

## Sources

- [Claude API docs: Pricing](https://platform.claude.com/docs/en/about-claude/pricing)
- [Claude API docs: Claude Opus 5.5 overview (also pricing, what's new, Anthropic announcement)](https://platform.claude.com/docs/en/models/opus-5-5/overview)
- [Anthropic - Introducing Claude Opus 5.5](https://www.anthropic.com/claude-opus-5-5)
- [Claude API docs: Models overview](https://platform.claude.com/docs/en/about-claude/models/overview)

Canonical: https://neomanex.com/models/claude-opus-5-5