Anthropic launched cache diagnostics in public beta for Messages requests.

Builders now get a cache_miss_reason showing where a prompt cache prefix diverged from the previous turn.

It sits inside Messages requests: pass diagnostics.previous_message_id and include the beta header to diagnose prompt cache misses.

• Aug 25, 2026OpenAI models page removed visible model selection documentation text.
• Aug 25, 2026Anthropic model card removed Claude Fable 5 and Claude Mythos 5 selection guidance
• Aug 25, 2026OpenAI removed business pricing copy listing GPT-5.6 and GPT-Image-2 rates.

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