Response cancellation broken due to tuple assignment bug in Realtime API

[gn00295120]

Summary

Response cancellation is completely broken in the Realtime API due to trailing commas creating tuples instead of booleans.

Bug Location

src/agents/realtime/openai_realtime.py lines 434 and 619

Description

The trailing commas in the automatic_response_cancellation_enabled assignment create single-element tuples instead of booleans:

# Current (buggy) code:
automatic_response_cancellation_enabled = (
    session
    and session.audio is not None
    and session.audio.input is not None
    and session.audio.input.turn_detection is not None
    and session.audio.input.turn_detection.interrupt_response is True,  # ← Trailing comma
)

Impact

The condition if not automatic_response_cancellation_enabled: always evaluates to False because:

• With trailing comma: type = tuple, value = (False,), not (False,) = False
• Non-empty tuples are always truthy in Python

Result: _cancel_response() is never called, breaking response cancellation when interrupt_response=False.

Reproduction

# Demonstrates the bug:
enabled = (False,)  # tuple
print(not enabled)  # False - _cancel_response() NOT called!

# Expected behavior:
enabled = False  # bool  
print(not enabled)  # True - _cancel_response() IS called

Environment

• Introduced in: PR feat: #1614 gpt-realtime migration (Realtime API GA) #1646 (commit 9168348, 2025-09-12)
• Affects: All Realtime API users with interrupt_response=False

Fix

Remove the trailing commas on lines 434 and 619.

I'll submit a PR with the fix.

[gn00295120]

Potentially Related Issues

This bug may be the root cause of the following reported issues:

Highly likely related:

• Realtime guardrails: "Conversation already has an active response in progress" error #1907 - Guardrail interruption fails with "Conversation already has an active response in progress" error
  • User specifically notes: "response.cancel is triggered if turn_detection.interrupt_response is not set"
  • This aligns perfectly with our bug: when interrupt_response=False, the tuple bug prevents _cancel_response() from being called
  • Timeline: Issue reported 2025-10-16 (34 days after bug introduced in PR feat: #1614 gpt-realtime migration (Realtime API GA) #1646)

Possibly related:

• Python Realtime Voice Agent doesn’t handle output guardrails like Node.js SDK #1912 - Output guardrails don't work correctly (Python vs Node.js behavior difference)
  • Manual session.interrupt() doesn't work as expected
  • May be partially caused by broken response cancellation logic

Both issues appeared after PR #1646 (2025-09-12) which introduced this bug.

[seratch]

Yeah #1912 could be related too, but I am not 100% sure about it. Once a new version including this fix is released, I will ask the reporter to try the latest version out.