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ToolCallStartEvent

Interface: ToolCallStartEvent

Defined in: packages/typescript/ai/src/types.ts:902

Emitted when a tool call starts.

@ag-ui/core provides: toolCallId, toolCallName, parentMessageId? TanStack AI adds: model?, toolName (deprecated alias), index?, metadata?

Extends

  • ToolCallStartEvent

Indexable

ts
[k: string]: unknown
[k: string]: unknown

Properties

index?

ts
optional index: number;
optional index: number;

Defined in: packages/typescript/ai/src/types.ts:911

Index for parallel tool calls


metadata?

ts
optional metadata: Record<string, unknown>;
optional metadata: Record<string, unknown>;

Defined in: packages/typescript/ai/src/types.ts:916

Provider-specific metadata to carry into the ToolCall. Untyped at the event layer because events flow through a discriminated union that does not survive generics; adapters cast it to their typed TToolCallMetadata shape when emitting.


model?

ts
optional model: string;
optional model: string;

Defined in: packages/typescript/ai/src/types.ts:904

Model identifier for multi-model support


toolName

ts
toolName: string;
toolName: string;

Defined in: packages/typescript/ai/src/types.ts:909

Deprecated

Use toolCallName instead (from @ag-ui/core spec). Kept for backward compatibility.