On September 22, 2026, Anthropic released Claude Opus 5.5, the first entry in its new 5.5 model family. The update is less a feature launch than a quiet efficiency revolution: the same frontier-level intelligence as Opus 5, at 40% lower typical workload cost and with 30%+ faster output.
What's cheaper, and by how much
The new pricing lands at $4 per million input tokens and $20 per million output tokens — down from $5 and $25 with Opus 5. Cache reads drop 60% to $0.20 per million, and cache writes fall from $6.25 to $5. For teams running long-context or heavily cached pipelines, the savings are significant. A Fast Mode variant doubles the speed again (roughly 2.5× versus the standard tier) at $8 input/$40 output per million tokens.
Benchmarks that matter
The improvement over Opus 5 is sharpest on agentic tasks. On Terminal-Bench 4.0, Opus 5.5 scores 66.4% versus Opus 5's 52.3% — a 14-point jump on a benchmark designed to stress-test long-horizon coding agents. Computer use on OSWorld 2.0 climbs from 74.0% to 81.8%. On the GDPval-AA v2.1 knowledge-work benchmark, it reaches Elo 1846 (up from 1708).
A demonstration shared by Anthropic shows Opus 5.5 completing a 680,000-line codebase migration in under one day — a task that would previously have required significant human coordination across multiple sessions.
Safety and responsible deployment
The release includes cybersecurity guardrails that automatically reroute certain classes of sensitive tasks to Opus 4.8 rather than refusing them outright, along with biology safeguards matching Fable 5.1. Anthropic reports an 85% reduction in boundary circumvention attempts compared to prior models. EU AI Act watermarking is included by default. Organizations working in life sciences or security research can apply for access through the Life Sciences and Cyber Verification Programs.
Availability
Claude Opus 5.5 is available now via the Claude Platform (model ID: claude-opus-5-5), Amazon Web Services, Google Cloud, and Microsoft Azure. Zero-data-retention mode is supported for enterprise customers. Anthropic has indicated that Sonnet 5.5 and Haiku 5.5 will follow within weeks.
For most production use cases — especially agentic coding, document workflows, and computer use — the upgrade path from Opus 5 to Opus 5.5 is straightforward: same API surface, lower cost, faster responses, better results.