Type Alias: ToolHandler

type ToolHandler = (
  args: unknown,
  ctx: DispatchContext,
  meta: Registry,
) =>
  | string
  | Uint8Array
  | SpooledArtifact
  | Media
  | Media[]
  | Promise<string | Uint8Array | SpooledArtifact | Media | Media[]>;

Defined in: src/lib/classes/tool.ts:57

The execution function for a Tool.

Parameters

Parameter	Type
args	unknown
ctx	DispatchContext
meta	Registry

Returns

| string | Uint8Array | SpooledArtifact | Media | Media[] | Promise< | string | Uint8Array | SpooledArtifact | Media | Media[]>

Remarks

Receives the raw arguments passed to the executor, the active @nhtio/adk!DispatchContext, and the tool's metadata registry.

Return shapes:

• string / Uint8Array — opaque serialised output. The ADK does not persist the bytes itself; the consumer's executor middleware is responsible for storing them and wrapping them via tool.artifactConstructor?.() ?? SpooledArtifact when assembling the ToolCall record.
• @nhtio/adk!SpooledArtifact — a pre-built, reader-backed result. Return this when the handler has streamed bytes into storage and wrapped the reader; the consumer passes it through without materialising or re-spooling it. Its concrete class determines the forged artifact_* query tools.
• @nhtio/adk!Media / Media[] — explicit-modality silo. Bypasses Tool.artifactConstructor — the handler returns the final result shape directly. The LLM battery renders each Media as a provider-specific content block.