Function: createSubagentTypeGate()

function createSubagentTypeGate(allowedTypes): HookCallback;

Defined in: core/hooks/subagentTypeGate.ts:17

PreToolUse hook restricting the Agent tool to the subagent types this session actually registered (session.ts's agents: {...}, from AgentSpec.buildSubagents()) — confirmed empirically that the Agent SDK also exposes a built-in "general-purpose" subagent_type regardless of what agents lists, and that spawning one that way inherits the whole session's own tools (including Bash, whenever any opt-in subagent turned it on) rather than the narrow AgentDefinition.tools each declared subagent actually declares. Without this hook, that built-in type is a way to route around subagentBashGate.ts entirely: once inside it, agent_id is set exactly like an intended subagent, so the Bash-from-main-thread check alone can't tell them apart — this is exactly what happened in practice in a real consuming agent (the model delegated a plain file deletion to a spontaneous "general-purpose" agent to get at Bash, instead of using its own tools and leaving the stray file alone).

Parameters

Parameter	Type
allowedTypes	readonly string[]

Returns

HookCallback