Agent SDK reference - TypeScript changedagent-sdk/typescript
Nearest release: v2.1.304, published 2 hours after upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 19 Oct 2026 17:22 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 19 Oct 2026 17:37 UTC.
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526526| `outputFormat` | `{ type: 'json_schema', schema: JSONSchema }` | `undefined` | Define output format for agent results. See [Structured outputs](/docs/en/agent-sdk/structured-outputs) for details |
527527| `outputStyle` | `string` | `undefined` | Not an `Options` field. Set `outputStyle` in the inline [`settings`](/docs/en/settings) object or a settings file instead. See [Activate an output style](/docs/en/agent-sdk/modifying-system-prompts#activate-an-output-style) |
528528| `pathToClaudeCodeExecutable` | `string` | Auto-resolved from bundled native binary | Path to Claude Code executable. Only needed if optional dependencies were skipped during install or your platform isn't in the supported set |
529| `permissionMode` | [`PermissionMode`](#permissionmode) | `undefined` | Permission mode for the session. If you omit it, the session can start in auto mode. See [Permission modes](/docs/en/agent-sdk/permissions#permission-modes) for how Claude Code picks the starting permission mode |
529| `permissionMode` | [`PermissionMode`](#permissionmode) | `undefined` | Permission mode for the session. If you omit it and nothing else sets a permission mode, such as a [`permissions.defaultMode`](/docs/en/settings-reference#permissions-defaultmode) setting, the session starts in `default`. See [Permission modes](/docs/en/agent-sdk/permissions#permission-modes) |
530530| `permissionPromptToolName` | `string` | `undefined` | MCP tool name for permission prompts |
531531| `permissionPrompts` | `'host' \| 'none'` | `'host'` | Who answers permission prompts: `'host'` routes them to your [`canUseTool`](#canusetool) callback or the `permissionPromptToolName` tool, and `'none'` [denies the calls that would have prompted](/docs/en/agent-sdk/permissions#how-permissions-are-evaluated). Requires Claude Code v2.1.259 or later |
532532| `persistSession` | `boolean` | `true` | When `false`, disables session persistence to disk. Sessions cannot be resumed later |
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52675267When Claude Code [moves a long MCP tool call to the background](/docs/en/mcp#automatic-backgrounding-of-long-tool-calls), the `tool_result` block for that call holds only a placeholder and the call's real result arrives in this notification. Match the notification to the call with `tool_use_id`. On a `completed` notification, `resource_links` lists the files the tool returned by reference as [`SDKMcpResourceLink`](#sdkmcpresourcelink) entries, with the same 50-link and 64 KiB limits as [`tool_use_result.resourceLinks`](#sdkusermessage). Claude Code omits `resource_links` when the result had no links and on notifications for tasks that aren't MCP tool calls. `resource_links` requires Agent SDK v0.3.257 or later.
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5269Claude Code prepends a notice to every task notification it sends to the model, except deliveries stamped with the [`scheduled-trigger` subkind](#task-notification-subkinds), which carry an assigned-task framing instead. The notice states that no human input has occurred, so the model doesn't treat the notification as a user instruction or approval.
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5271To detect a task-notification turn, check `origin.kind === "task-notifica
5269Claude Code prepends a notice to every task notification it sends to the model, except deliveries stamped with the [`scheduled-trigger` subkind](#task-notification-subkinds), which carry an assigned-task framing instead. The notice states that no human input has occurred, so the model doesn't treat the notification as a user instruction or ap
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