Anthropic

Claude Opus 5.5 is Anthropic's September 22, 2026 Opus-class model for long-running agentic coding and knowledge work, and the first model in the Claude 5.5 family. The Claude API ID is claude-opus-5-5, with a 1M-token context window, 128K synchronous max output, adaptive thinking that cannot be disabled, and default effort medium. Anthropic prices it at $4 input and $20 output per million tokens and says typical workloads cost about 40% less to run than Opus 5.

Context tokens

1,000,000

Knowledge Cutoff

2026-06

Max output tokens

128,000

Claude Fable 5.1 is Anthropic's September 1, 2026 generally available flagship for demanding reasoning and long-horizon agentic coding, research, and document work. The API ID is claude-fable-5-1, with a 1M-token context window, 128K max output, adaptive thinking, and default high effort. Anthropic keeps the $10/$50 input/output list price of Fable 5 while cutting cache reads to $0.25 per million tokens.

Claude Sonnet 5 is Anthropic's balanced current Sonnet model for agentic coding, tool use, and production knowledge work, offering a stronger cost-performance lane than prior Sonnet releases.

Claude Haiku 4.5 is Anthropic's fastest current Claude model with near-frontier intelligence for high-volume and latency-sensitive workloads.