Added:
- Launched Claude Opus 4.8, the most capable generally available model, with default 1M token context window and 128k max output tokens, supporting the same tools and platform features as Opus 4.7.
- Launched mid-conversation system messages on Opus 4.8, allowing system messages after user turns in the messages array without a beta header, preserving prompt cache hits when instructions change.
- Documented the stop_details field on refusal responses, which returns a category (cyber, bio, or null) and a human-readable explanation for routing refusals.
- Added the standalone heading "Long context pricing" (likely a new section or note).
- Added the computer_20250124 tool entry (relocated from a previous section).

Changed:
- Updated the 1M token context window beta note for Opus 4.6: removed the phrase "Long context pricing applies to requests exceeding 200k input tokens" and replaced with simply "applies to requests exceeding 200k input tokens" (dropping the "Long context pricing" qualifier).
- Relocated the computer_20250124 tool entry from an earlier list of tool versions to a later section.

Removed:
- Removed the original 1M token context window beta line for Opus 4.6 (which included "Long context pricing applies to requests exceeding 200k input tokens").
- Removed the computer_20250124 tool entry from its original location (it was re-added elsewhere, representing a relocation).