[claude-agent-sdk-python] elicitation / request_user_dialog control requests answered with error

## Observed symptom elicitation and request_user_dialog control requests are answered with an error; supportedDialogKinds and perTaskStopAffordance are never sent ## Summary The inbound control-request handler accepts `can_use_tool`, `hook_callback`, and `mcp_message`; any other subtype is answered with an error response, `Unsupported control request subtype: <name>` (`_internal/query.py:593-594`). The TypeScript SDK handles `elicitation` and `request_user_dialog` through `onElicitation` and `onUserDialog` (`sdk.d.ts:1683, 1697`), and declares what it supports in the initialize request via `supportedDialogKinds` and `perTaskStopAffordance` (`sdk.d.ts:1719, 1739, 4338, 4342`). The Python initialize request carries `hooks`, `agents`, `excludeDynamicSections`, `systemPromptSnapshot`, `skills`, and `forwardSubagentText` only (`_internal/query.py:285-300`). Per the TypeScript contract, a host that does not declare `perTaskStopAffordance` gets background ## Literal error text ``` elicitation answered with error ``` ## Environment GitHub issue anthropics/claude-agent-sdk-python #1296; state=open ## Trigger / context ## Summary The inbound control-request handler accepts `can_use_tool`, `hook_callback`, and `mcp_message`; any other subtype is answered with an error response, `Unsupported control request subtype: <name>` (`_internal/query.py:593-594`). The TypeScript SDK handles `elicitation` and `request_user_dialog` through `onElicitation` and `onUserDialog` (`sdk.d.ts:1683, 1697`), and declares what it supports in the initialize request via `supportedDialogKinds` and `perTaskStopAffordance` (`sdk.d.ts:1719, 1739, 4338, 4342`). The Python initialize request carries `hooks`, `agents`, `excludeDynamicSections`, `systemPromptSnapshot`, `skills`, and `forwardSubagentText` only (`_internal/query.py:285-300`). Per the TypeScript contract, a host that does not declare `perTaskStopAffordance` gets background tasks killed on interrupt, and dialog kinds not declared are never offered. Checked at v0.2.159 (bundled CLI 2.1.281); paths are under `src/claude_agent_sdk/`. TypeScript references are to `@anthropic-ai/claude-agent-sdk` 0.3.280, `sdk.d.ts`. ## Repro With a custom `Transport`, yield `{"type": "control_request", "request_id": "x", "request": {"subtype": "elicitation", "elicitation": {"message": "pick one"}}}` after the initialize response, then read what the SDK writes. Observed: `{"subtype": "error", "request_id": "x", "error": "Unsupported control request subtype: elicitation"}`; same for `request_user_dialog`. ## Expected Callbacks for elicitation and user dialogs, and the two init ## Source evidence - https://github.com/anthropics/claude-agent-sdk-python/issues/1296 (2026-09-30T14:51:31Z) — GitHub issue #1296 (open) ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T09:39:37.643698Z - scout_id: C6b25309206 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome.