startTool

TypeScript SDK reference

startTool

▸ startTool(opts): Tool

Start a Tool span. Parent resolution (matches the design’s “flat by default, hierarchical if you nest”):

• If an LLM is active, the Tool nests under it.
• Otherwise, the Tool is a sibling under the current Turn.

Throws if neither a Turn nor an LLM is active.

Parameters

Name	Type
opts	ToolInit

Returns

Tool

Example

weave.startTool({
  name: 'get_weather',
  args: JSON.stringify({city: 'Tokyo'}),
  toolCallId: 'call_t1',
});

Example

weave.startTool({
  name: 'get_weather',
  args: JSON.stringify({city: 'Tokyo'}),
  toolCallId: 'call_t1',
  startTime: new Date('2026-05-29T10:00:00.800Z'),
});

Defined in

src/genai/api.ts:103

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