RuntimeError in AgentTask.__await_impl finally block when SpeechHandle is already interrupted

[simllll]

Description

After upgrading to a version that includes #4730, we're seeing a RuntimeError when a SpeechHandle gets interrupted during an AgentTask execution. The __await_impl finally block tries to restore speech_handle.allow_interruptions without checking if the handle is already interrupted.

Error

RuntimeError: Cannot set allow_interruptions to False, the SpeechHandle is already interrupted

Traceback (most recent call last):
  File ".venv/lib/python3.14/site-packages/livekit/agents/voice/generation.py", line 609, in _traceable_fnc_tool
    val = await function_callable()
  ...
  File ".venv/lib/python3.14/site-packages/livekit/agents/voice/agent.py", line 832, in __await_impl
    speech_handle.allow_interruptions = old_allow_interruptions
  File ".venv/lib/python3.14/site-packages/livekit/agents/voice/speech_handle.py", line 128, in allow_interruptions
    raise RuntimeError(
        "Cannot set allow_interruptions to False, the SpeechHandle is already interrupted"
    )

Context

We await prebuilt AgentTask subclasses (e.g. GetEmailTask, GetListTask) inside a function tool. The SDK correctly sets up inline_task=True on the tool's asyncio task via _set_activity_task_info in generation.py.

The issue is in __await_impl's finally block which unconditionally restores allow_interruptions:

# agent.py, __await_impl finally block
if speech_handle:
    speech_handle.allow_interruptions = old_allow_interruptions

If the user interrupts during the task (or the handle is force-interrupted via cancel() or the new _schedule_speech interrupt paths added in #4730), the handle is already in an interrupted state and the setter raises RuntimeError.

Likely cause

PR #4730 added several new paths that force-interrupt speech handles:

1. AgentTask.cancel() calls self._activity.interrupt(force=True)
2. _schedule_speech now calls speech.interrupt(force=True) before raising when scheduling is paused/draining
3. _aclose_impl loops through active AgentTasks and calls cancel()

These new interruption paths can leave a speech handle in an interrupted state when __await_impl's finally block runs, but the finally block doesn't guard against this.

Suggested fix

Guard the restoration in the finally block:

if speech_handle and not speech_handle.interrupted:
    speech_handle.allow_interruptions = old_allow_interruptions

Versions

• livekit-agents: 1.4.3
• Python: 3.14