ToolCallId

ToolCallId = Brand<string, "ToolCallId">

Defined in: packages/protocol/src/lib/tool-call-id.ts:11

Opaque identifier assigned by a realtime provider (OpenAI, Google, …) to a single tool call, correlating that call with the tool result sent back for it. Format is intentionally unspecified — Maelstrom treats it as an opaque string minted by the provider, never by the client.