Anthropic API

Claude Opus 5.5 delivers a major performance jump over Opus 5 in agentic coding, computer use, and knowledge work while costing 40% less to run, with 20% cheaper input/output tokens and 60% cheaper cache reads, plus over 30% faster output generation; it also scores highest to date on Anthropic's automated behavioral audit and includes safeguards similar to those on Claude Fable 5.1 due to comparable biology and cybersecurity capability. No breaking changes accompany this release, though Pro, Max, Team, and seat-based Enterprise plans now get increased five-hour usage limits and a saveable rate limit reset.

Matters for: Engineering teams running large-scale automated code migrations or agentic coding workflows where per-token and cache-read costs at scale directly affect budget.

Anthropic released Claude Fable 5.1 (generally available) and Claude Mythos 5.1 (available via trusted access programs), offering higher performance on coding, agentic research, and knowledge-work benchmarks than Fable 5, along with reduced pricing on cache reads that cuts typical workload costs by about 25% and agentic work costs by up to 45%. The models also introduce Enterprise Frontier Safeguards for customer-controlled data storage (rolling out this fall), zero data retention in the interim for eligible customers, and safeguards that reduce cybersecurity false positives by 60% while allowing vulnerability discovery (but not exploit development).

Matters for: Relevant for quantitative trading and finance firms running long, multi-step agentic coding tasks, and for enterprise teams needing zero data retention or customer-controlled data storage for compliance reasons.

The Anthropic API now provides access to Claude Fable 5.1 and Mythos 5.1, described as the most advanced models for coding and knowledge work, plus Claude Opus 5, which offers frontier-level intelligence close to Claude Fable 5 at half the price. Additionally, HIPAA configuration for the Claude Platform (API) is now self-serve, letting an eligible admin review the BAA, download the implementation guide, and enable HIPAA configuration in a single flow without prior manual setup.

Matters for: Relevant for teams building agentic coding tools on the Anthropic API who need lower-cost high-capability models, and for organizations in regulated healthcare environments that require HIPAA-compliant API access.