--- url: >- https://adk.nht.io/api/@nhtio/adk/turn_runner/interfaces/TurnToolCallContent.md description: >- A tool call invocation emitted during a turn, including its result once available. --- # Interface: TurnToolCallContent Defined in: [lib/types/turn\_runner.ts:56](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L56) A tool call invocation emitted during a turn, including its result once available. ## Remarks Emitted at least once when the model requests a tool call. The same `id` is re-emitted with `results` populated and `isComplete` set to `true` after the tool has been executed. If execution fails, `isError` is `true` and `results` contains the error detail. ## Properties | Property | Type | Description | Defined in | | ------------------------------------------------ | ----------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- | ----------------- | ----- | ------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------- | | `args` | `unknown` | Arguments the model supplied for the tool call. | [lib/types/turn\_runner.ts:66](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L66) | | `checksum` | `string` | `sha256({ tool, args })` over the raw arguments. Doubles as the **cross-bus join key**: equal to [ToolExecutionStartEvent.callId](ToolExecutionStartEvent.md#property-callid) / [ToolExecutionEndEvent.callId](ToolExecutionEndEvent.md#property-callid) and to [@nhtio/adk!ToolCall.checksum](../../forge/classes/ToolCall.md#property-checksum). Collides by design for identical `(tool, args)` within a turn — that is what [@nhtio/adk!DispatchContext.toolCallCount](../../types/interfaces/DispatchContext.md#toolcallcount) counts — so order or disambiguate repeated calls by `createdAt` / `updatedAt`, not by `checksum` alone. | [lib/types/turn\_runner.ts:74](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L74) | | `completedAt?` | `DateTime`<`boolean`> | Timestamp when the tool call completed (successfully or not). | [lib/types/turn\_runner.ts:102](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L102) | | `createdAt` | `DateTime` | Timestamp when this tool call was first emitted. | [lib/types/turn\_runner.ts:76](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L76) | | `id` | `string` | Stable stream id for this tool call; ties the initial request to its result on **this** bus (the announce emission and the completion emission share it). This is the model/stream id, not a cross-bus key — to correlate with the observability `toolExecution*` events, use `checksum`. | [lib/types/turn\_runner.ts:62](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L62) | | `isComplete` | `boolean` | `true` once the tool call has finished (successfully or not). | [lib/types/turn\_runner.ts:98](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L98) | | `isError` | `boolean` | `true` when the tool execution produced an error; inspect `results` for detail. | [lib/types/turn\_runner.ts:100](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L100) | | `results?` | `unknown` | Result returned by the tool, or error detail when `isError` is `true`. Absent until execution completes. **Remarks** Shape depends on the underlying tool kind. For a normal [@nhtio/adk!Tool](../../forge/classes/Tool.md) call, this carries one or more [@nhtio/adk!SpooledArtifact](../../spooled_artifact/classes/SpooledArtifact.md) instances (single artifact or `SpooledArtifact[]`) wrapping the bytes returned by the handler, or one or more [@nhtio/adk!Media](../../common/classes/Media.md) instances (single `Media` or `Media[]`) when the handler took the explicit-modality return path. For an [@nhtio/adk!ArtifactTool](../../forge/classes/ArtifactTool.md) call, this is the raw string the handler emitted (`Tokenizable.toString()`-equivalent) — already the model-visible answer. Type stays `unknown` to keep this event payload narrow; the underlying `ToolCall.results` is `Tokenizable | SpooledArtifact | SpooledArtifact[] | Media | Media[]`. **See** [@nhtio/adk!ToolCall.results](../../forge/classes/ToolCall.md#property-results) | [lib/types/turn\_runner.ts:96](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L96) | | `tool` | `string` | Name of the tool the model has requested. | [lib/types/turn\_runner.ts:64](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L64) | | `updatedAt` | `DateTime` | Timestamp of the most recent update to this tool call (e.g. when results arrived). | [lib/types/turn\_runner.ts:78](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/types/turn_runner.ts#L78) |