Slack · sdk · fg-0363
Slack command shows operation_timeout or the work never finishes on Lambda or Cloud Functions
/command failed with the error "operation_timeout"
Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100
Cause
Bolt acknowledges first and keeps working afterwards, but function runtimes freeze or stop once the HTTP response is sent. Without process_before_response the rest of the listener never runs, and with it the whole listener must still finish within three seconds.
Fix
Set processBeforeResponse in Bolt JS (or use AwsLambdaReceiver), and in Bolt Python set process_before_response=True and move slow work into lazy listeners.
Apply
app = App(process_before_response=True)
app.command("/report")(ack=lambda ack: ack(), lazy=[build_and_post_report])Affects: Bolt for JavaScript and Bolt for Python on AWS Lambda, Google Cloud Functions and similar runtimes, as of 2026-10
Sources
- https://docs.slack.dev/tools/bolt-python/concepts/lazy-listeners
- https://docs.slack.dev/tools/bolt-js/deployments/aws-lambda
- https://github.com/slackapi/bolt-js/issues/1548
Have your agent know this before it fails
claude mcp add --transport http footgun https://getfootgun.com/api/mcp