Function: createSubagentForegroundGate()

function createSubagentForegroundGate(allowedTypes): HookCallback;

Defined in: core/hooks/subagentForegroundGate.ts:19

PreToolUse hook forcing run_in_background: false on every Agent-tool call that spawns one of this session's own subagents. The Agent tool's own input schema defaults to background execution ("Agents run in the background by default", its own description says) unless the model explicitly opts out per call — confirmed empirically (in a real consuming agent) that with a less directive prompt, the model left it on that default, the main turn's "result" fired before the subagent had done anything at all, and the whole invocation was silently lost: no file written, no error, nothing — because the caller's message loop had no code watching for background-task completion (SDKTaskStartedMessage/SDKTaskUpdatedMessage/etc. are never handled). Setting background: false on the AgentDefinition itself (session.ts's agents: {...}) does NOT fix this — confirmed empirically it has no effect on which way the model's own per-call run_in_background input resolves. Rewriting the tool input here, before it ever executes, is the only lever that actually forces synchronous execution regardless of what the model asked for.

Parameters

Parameter	Type
allowedTypes	readonly string[]

Returns

HookCallback