[stanleyphu]

Stack. This is #762, split into four PRs for review. Merge them in order; after each merge I'll rebase the next one onto main.

1. chore(feature-flags): Parse and evaluate flag configurations locally #764 Configuration and evaluation
2. feat(feature-flags): Evaluate feature flags locally with a polling runtime client #765 Sync runtime client
3. feat(feature-flags): Add an async feature flags runtime client #766 Async runtime client ← this PR
4. chore(feature-flags): Keep the runtime clients safe across fork() #767 Fork safety

Description

AsyncFeatureFlagsRuntimeClient, created from AsyncWorkOSClient, polls in an asyncio task. It has the same evaluation, retries, listeners and status as the sync client in #765.

flags = async_workos.create_feature_flags_runtime_client()
await flags.start()
await flags.wait_until_ready(timeout=5)
flags.is_enabled("new-checkout", {"organization": "org_123"})  # still synchronous

• It polls through the AsyncWorkOSClient's own request() with max_retries: 0, so retries follow the runtime client's policy. asyncio.wait_for enforces request_timeout exactly.
• Listeners may be plain functions or coroutines. Coroutines are awaited in order, each in a task of its own, so a CancelledError inside one only ends that listener and polling continues.
• close() cancels the polling task, and any listener it's running, and waits for it to finish. Every caller waits, including concurrent ones. When close() is called from a listener running inside that task, it doesn't wait, because the task exits once the listener returns.

Where to look: _async.py mirrors _sync.py method for method, so reading them side by side is quickest. The real differences are _fetch and _refresh_locked (timeouts) and _drain, _deliver and _await_listener (running coroutine listeners).

How I checked it:

• The full feature flags runtime lab passes against this branch: 87 of 87 checks. That's 47 for Python, including the 7 asyncio checks, and 40 for Node. The Python bridge suite passes 5 of 5.
• nox -s ci passes locally: 3,715 tests.

Documentation

Does this require changes to the WorkOS Docs? E.g. the API Reference or code snippets need updates.

[x] Yes

The docs PR noted on #765 covers this client too.

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no new actionable issues were found.

Summary

Adds AsyncFeatureFlagsRuntimeClient with background polling, synchronous flag evaluation, and coroutine listeners.

• Async WorkOS apps can poll flags and check them locally.
• Async listeners receive ordered updates without stopping polling.

_{Reviews (6) · Last reviewed commit: "fix(feature-flags): Make every async clo..." · Reviewed by Greptile}

[stanleyphu]

@greptileai review

[stanleyphu]

@greptileai review

[stanleyphu]

@greptileai review

[stanleyphu]

@greptileai review