Interface: ToolCallStartEvent

Emitted when a tool call starts.

Extends

optional index: number;

optional index: number;

Index for parallel tool calls

optional model: string;

optional model: string;

Model identifier for multi-model support

optional parentMessageId: string;

optional parentMessageId: string;

ID of the parent message that initiated this tool call

optional providerMetadata: Record<string, unknown>;

optional providerMetadata: Record<string, unknown>;

Provider-specific metadata to carry into the ToolCall

optional rawEvent: unknown;

optional rawEvent: unknown;

Original provider event for debugging/advanced use cases

timestamp: number;

timestamp: number;

toolCallId: string;

toolCallId: string;

Unique identifier for this tool call

toolName: string;

toolName: string;

Name of the tool being called

type: "TOOL_CALL_START";

type: "TOOL_CALL_START";