{"version":"2.1.275","anchor":"toolcall-hook-event-schema-gains-a-measure-combinator","canonical_anchor":"toolcall-hook-event-schema-gains-a-measure-combinator","heading":"tool.call hook-event schema gains a measure combinator","tier":"internal","area":"Hooks","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.275\/e\/toolcall-hook-event-schema-gains-a-measure-combinator","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.275","markdown":"### tool.call hook-event schema gains a `measure` combinator\n\nThe tool.call hook event gained a 'measure' step that combines context across related events\n\n**Unclear.** What practical difference the new 'measure' combinator makes to hook authors versus the previous 'carry' function is not stated.\n\n**What**\n\nThe internal descriptor for the `tool.call` hook event, used alongside `PreToolUse` (a hook point that runs before a tool call executes and can block it), now includes a `measure` function. This function combines the context of one event with the contexts of a list of related events, replacing what was previously a simpler `carry` function.\n\n**Why**\n\nThis is internal plumbing for how hook event context is assembled; the finding doesn't indicate a directly user-visible change.\n\n- Area: Hooks\n- Names: `tool.call`\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 1\/5"}