The new Opus 5.5 AI model enters stealth testing under the codename `claude-wafer-eap` with a target launch on Tuesday. Input costs are $4 per Mtok and output costs are $20 per Mtok, with cache reads at $0.2 and writes at $5 per Mtok. The update eliminates forced tool use and restricts the model to an adaptive thinking mode with no "off" option.

Reuters reports the launch follows the Sept 3 release of GPT-6 Astra, which pressured Anthropic's standing in the enterprise market. The company provided partners with a 24 hour access window to the checkpoint, though the official rollout could arrive as early as Monday of the upcoming week.