Permission decisions can now name the hook that made them

What

Before Claude Code runs a tool (such as a shell command), it decides whether to allow it, ask you, or refuse. The record of that decision held decision, reason and rule. It now also has an optional hook field saying which hook made the decision. A hook is a piece of plugin or user code that runs at a set moment.

• Plugin hooks: a tool.check hook can now return a hook string with its decision. A non-string value is rejected with the message "a reason, rule or hook that is not a string".
• Filling the field: hook comes from the hook's own answer or is looked up from the decision's decisionReason.hookName, ignoring tool.check.
• Nested commands: the rule lookup now searches inside nested subcommandResults. Before, it checked only one level deep, so a compound command could miss the rule that decided it.

Why

Tools and SDK users reading these decisions can tell when a hook, and which one, allowed or blocked a tool. Compound commands now report their deciding rule more reliably.