BeforeToolCallEvent

Defined in: src/hooks/events.ts:181

Event triggered just before a tool is executed. Fired after tool lookup but before execution begins. Hook callbacks can set cancel to prevent the tool from executing.

Extends

• HookableEvent

Constructors

Constructor

new BeforeToolCallEvent(data): BeforeToolCallEvent;

Defined in: src/hooks/events.ts:198

Parameters

Parameter	Type
data	{ agent: LocalAgent; toolUse: { name: string; toolUseId: string; input: JSONValue; }; tool: Tool; }
data.agent	LocalAgent
data.toolUse	{ name: string; toolUseId: string; input: JSONValue; }
data.toolUse.name	string
data.toolUse.toolUseId	string
data.toolUse.input	JSONValue
data.tool	Tool

Returns

BeforeToolCallEvent

Overrides

HookableEvent.constructor

Properties

type

readonly type: "beforeToolCallEvent";

Defined in: src/hooks/events.ts:182

---

agent

readonly agent: LocalAgent;

Defined in: src/hooks/events.ts:183

---

toolUse

readonly toolUse: {
  name: string;
  toolUseId: string;
  input: JSONValue;
};

Defined in: src/hooks/events.ts:184

name

name: string;

toolUseId

toolUseId: string;

input

input: JSONValue;

---

tool

readonly tool: Tool;

Defined in: src/hooks/events.ts:189

---

cancel

cancel: string | boolean = false;

Defined in: src/hooks/events.ts:196

Set by hook callbacks to cancel this tool call. When set to true, a default cancel message is used. When set to a string, that string is used as the tool result error message.

Methods

toJSON()

toJSON(): Pick<BeforeToolCallEvent, "type" | "toolUse">;

Defined in: src/hooks/events.ts:213

Serializes for wire transport, excluding the agent reference, tool instance, and mutable cancel flag. Called automatically by JSON.stringify().

Returns

Pick<BeforeToolCallEvent, "type" | "toolUse">