defineTool

function defineTool<S, R>(config): Tool<InferToolInput<S>, R>;

Type Parameters

Type Parameter	Default type
S extends | ZodType<unknown, unknown, $ZodTypeInternals<unknown, unknown>> | StandardSchemaV1<unknown, unknown> | undefined	undefined
R	unknown

Parameters

Parameter	Type	Description
config	{ description: string; estimatedDurationMs?: number; execute: (args, ctx?) => Promise<R> | AsyncIterable<R, any, any>; filler?: string; idempotencyKey?: (args) => string; input?: S; interim?: string; interimAfterMs?: number; interruptible?: boolean; name?: string; needsApproval?: boolean; onError?: (error, args) => R | Promise<R>; output?: StandardSchemaV1<R, R>; parallelSafe?: boolean | ((args) => boolean); replay?: boolean; timeoutMs?: number; }	‐
config.description	string	‐
config.estimatedDurationMs?	number	Deprecated Use interimAfterMs.
config.execute	(args, ctx?) => Promise<R> | AsyncIterable<R, any, any>	‐
config.filler?	string	Deprecated Use interim.
config.idempotencyKey?	(args) => string	‐
config.input?	S	‐
config.interim?	string	‐
config.interimAfterMs?	number	‐
config.interruptible?	boolean	‐
config.name?	string	‐
config.needsApproval?	boolean	‐
config.onError?	(error, args) => R | Promise<R>	Turns a thrown error into a result the model can act on, instead of a generic failure. Return a value to recover; rethrow (or omit this) to let the error propagate. Runs only for genuine failures — never for a timeout, an abort, an input/output schema violation, or a control-flow signal, all of which must stay distinguishable from a result the tool chose to return.
config.output?	StandardSchemaV1<R, R>	‐
config.parallelSafe?	boolean | ((args) => boolean)	Safe to run concurrently with sibling calls in the same model-emitted batch. A function form receives the RAW (unvalidated) model args — classification happens before schema validation — and must not throw; a throw or a non-boolean return is treated as NOT parallel-safe. Never model-controlled: the model cannot assert this, only the tool author.
config.replay?	boolean	‐
config.timeoutMs?	number	‐

Returns

Tool<InferToolInput<S>, R>