Claude Fable 5 refusal responses can now return stop_details.category as reasoning_extraction.

Reverse engineering or duplicating model outputs now gets its own refusal category, separate from cyber and bio.

For builders handling refusals, Terms of Service blocks for output duplication are identifiable without a beta header.

• Jun 11, 2026OpenAI modelcard diff shows the API docs navigation content removed.
• Jun 11, 2026OpenAI pricing page removed visible API pricing content for GPT-5.5, GPT-5.4, and realtime.
• Jun 11, 2026Anthropic launched Claude Fable 5 and Claude Mythos 5 with 1M context and 128k max output.

This is the world we build in. It moves this fast. We move with it.