What
A new hook event type that fires once after every tool call in a batch has resolved, before the next model request.
Details
- Unlike
PostToolUsewhich fires per-tool and may run concurrently for parallel tool calls,PostToolBatchfires exactly once with the full batch - Hook input includes
tool_callsarray with{tool_name, tool_input, tool_use_id, tool_response}for each call - Supports
additionalContextreturn to inject content into the next model request - Can return
"stopAgent": trueto halt execution, showing"Execution stopped by PostToolBatch hook" - Available in hooks configuration under the event name
"PostToolBatch"
Evidence
Schema definition (search for "PostToolBatch") at line ~263664. Hook input schema describes "Fired once after every tool call in a batch has resolved, before the next model request".
Strings lifted out of the shipped bundle, so the claim above can be checked against them.