Software1 hOctober 16, 2026, 13:02

Claude Code 2.1.299–2.1.301 Changed Hook Behavior: 7 Things to Recheck

Releases 2.1.299, 2.1.300 and 2.1.301 of Claude Code, shipped October 14–15, 2026, include seven "Changed" entries that alter how existing hooks behave without any user edits. UserPromptSubmit now runs before a skill expands, and updatedInput is validated with unknown keys dropped.

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Claude Code 2.1.299–2.1.301 Changed Hook Behavior: 7 Things to Recheck

UserPromptSubmit now runs before a skill or custom slash command expands
A skill's front-matter UserPromptSubmit hook first runs on the next prompt
updatedInput is validated: unknown keys dropped, rejected input denies the call
setMode from a PermissionRequest hook is ignored in Cowork cloud sessions

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