Cancellation and Aborts

Prerequisites: - Familiarity with thread synchronization primitives

What you'll learn: - How signal cancellation works - Safe cancel patterns for CLI-driven work

TurnOptions Signal Contract

TurnOptions.signal accepts an object exposing: - is_set() -> bool

The SDK checks cancellation: - Before spawn - During stream consumption loop

Example With threading.Event

import threading
from codex_sdk import Codex

stop = threading.Event()
thread = Codex().start_thread()

# stop.set() can be called by another thread
try:
    result = thread.run("Perform deep analysis", {"signal": stop})
    print(result.final_response)
except RuntimeError as exc:
    print("Cancelled or failed:", exc)

Streaming Cancellation Pattern

streamed = thread.run_streamed("Long task", {"signal": stop})
for event in streamed.events:
    if should_cancel(event):
        stop.set()

Failure Modes

• Passing a signal-like object without is_set()
• Assuming cancellation returns partial turn summary like normal completion