Anthropic launches Claude Opus 5.5

What changed

Anthropic launched Claude Opus 5.5 with a 1M token context window and a 128k maximum output token limit. The model costs $4 input and $20 output per MTok, while Claude Opus 5 costs $5 input and $25 output. On Claude Opus 5.5 you cannot disable thinking, and the tool_choice types any and tool return a 400 error. The API also adds beta support for defining tools inside mid-conversation system messages.

What it means for Zabio customers

Both claude-opus-5-5 and claude-opus-5 are in the Zabio powerful tier and the auto routing uses both models. Developers pay the new $4 and $20 prices when calling Claude Opus 5.5 through Zabio.

What Zabio does

Catalog updated. claude-opus-5-5, Claude Opus 5 are in the Zabio catalog.

Source

We’ve launched Claude Opus 5.5 (claude-opus-5-5), a model for long-running agentic coding and knowledge work. It has a 1M token context window by default, 128k max output tokens, and always-on adaptive thinking, at $4 / $20 USD per MTok (Claude Opus 5 is $5 / $25).

Original announcement: Claude Platform release notes

Published automatically from the official announcement. Reviewed by a person within the day.