Anthropic Releases Claude Opus 5.5: Fable 5.1-Level Performance at 40% Lower Running Cost Than Opus 5
Anthropic has unveiled Claude Opus 5.5, the first model in its new Claude 5.5 family. According to the company, it delivers performance on par with Claude Fable 5.1 across most tasks while cutting running costs by 40% compared to Opus 5 on typical workloads at default settings. On Anthropic's internal benchmarks, Opus 5.5 leads in agentic coding, computer use, and knowledge work.
Deployment Options
Opus 5.5 is available as a managed API model. Anthropic has not released the model weights, so self-hosting is not possible. Developers can access it via the claude-opus-5-5 endpoint on the Claude Platform, Amazon Web Services, Google Cloud, and Microsoft Azure. Zero data retention is available, consistent with previous Opus models.
Benchmarks: Strong Lead, Not a Clean Sweep
Opus 5.5 scores reflect adaptive thinking at maximum effort with production safeguards enabled. The table below compares its performance against Fable 5.1, Opus 5, and GPT-6 Astra.
| Benchmark | Opus 5.5 | Fable 5.1 | Opus 5 | GPT-6 Astra |
|---|---|---|---|---|
| Terminal-Bench 4.0 | 66.4% | 55.8% | 52.3% | 57.9% |
| FrontierCode v1.1 | 54.4% | 50.3% | 48.0% | 53.3% |
| CursorBench 4.0 | 57.8% | 51.8% | 46.6% | n/r |
| GDPval-AA v2.1 (Elo) | 1846 | 1735 | 1708 | 1542 |
| OSWorld 2.0 | 81.8% | 80.7% | 74.0% | n/r |
| Terminal-Bench-Science 0.1 | 58.7% | 52.6% | 29.0% | 64.6% |
| AutomationBench | 40.0% | 31.4% | 26.9% | 41.4% |
Terminal-Bench 4.0 results for Opus 5.5 are reported at xhigh effort. GPT-6 Astra still leads on Terminal-Bench-Science and AutomationBench. Zapier ran AutomationBench without fallback models, meaning safeguard interventions were counted as failures. Anthropic also cautions that benchmark measurements can vary based on implementation details and environment.
via MarkTechPost