Start a background Claude Code run and return sessionId immediately. No final result is returned here. Main loop: call claude_code_check(action='poll'), store nextCursor, and keep polling until status becomes idle, error, or cancelled. If actions[] contains permission requests, answer them with claude_code_check(action='respond_permission'). respond_user_input is not supported. Adjust polling cadence to progress: poll faster while new events/actions are arriving, and slower when the session is quietly thinking. Long-running work is normal: Claude Code can keep working for 10+ minutes, especially with high/max effort, so wait for polling to settle before assuming it is stuck. If you want to continue after a run pauses or finishes, use claude_code_reply with the same sessionId instead of starting a new claude_code session. For runtime-authoritative tool names, call claude_code_check with pollOptions.includeTools=true.

Internal tools (runtime list when includeTools=true):

[agent]

• Task: Spawn subagent (must be in allowedTools)

• TaskOutput: Get subagent output

• TaskStop: Cancel subagent

• TeamDelete: Delete team (may need shutdown_approved first)

• TodoWrite: Task/todo checklist

[execute]

• Bash: Run shell commands

[file_read]

• Glob: Find files by glob pattern

• Grep: Search file contents (regex)

• Read: Read file contents (large files: use offset/limit or Grep)

[file_write]

• Edit: Targeted edits (replace_all is substring-based)

• NotebookEdit: Edit Jupyter notebook cells (Windows paths normalized)

• Write: Create or overwrite files

[interaction]

• AskUserQuestion: Ask user a question

[mcp]

• SubscribeMcpResource: Subscribe to an MCP resource stream

• SubscribePolling: Subscribe to periodic polling

• UnsubscribeMcpResource: Unsubscribe from an MCP resource stream

• UnsubscribePolling: Unsubscribe from periodic polling

[network]

• WebFetch: Fetch web page or API content

• WebSearch: Web search

Permission control: allowedTools pre-approves tools but is not a strict allowlist unless strictAllowedTools=true; disallowedTools always denies; other tools may require approval.

Send a follow-up to an existing session. Reuse the same sessionId instead of starting a new claude_code session when you want to continue. Returns immediately; poll with claude_code_check. Use diskResumeConfig only when the in-memory session is missing and disk resume is enabled.

List, inspect, cancel, or interrupt sessions.

Poll session state or answer a pending permission request.

POLLING FREQUENCY: Do NOT poll every turn. Claude Code tasks take minutes, not seconds.

• "running": sleep at least 2 minutes between polls; increase for complex tasks. Do NOT high-frequency poll — it wastes tokens.

• "waiting_permission": poll ~1s and respond quickly.

• "idle"/"error"/"cancelled": stop polling.

• Adapt interval based on task complexity and whether the previous poll returned new events.

Main loop: call action='poll', persist nextCursor, and use action='respond_permission' for approvals.