Tutorials

Inspect a failed run

Tutorial: deliberately break a flow, then use the Runs view, the step inspector, arrows, attempts and replay to find the cause, fix it, and recover interrupted runs with Resume.

#Goal

Learn to find out exactly why a flow failed, using a failure you create on purpose.

#Prerequisites

The HN search flow from Call an API in a flow, or any flow with an Agent step that replies in JSON.

#1. Break it on purpose

In the HN search flow, open the HTTP step and change the path of the kept value nbHits from nbHits to totalHits, a field the API does not return. Save and Run with rust.

Expected: the search step fails. Its card shows a failure label with the first line of the error, and the run ends Failed.

#2. Read the step

Open Runs (or Open run details in the editor's last-run strip).
Click the failed step.
Overview says why: The response has no value for nbHits. Check the path in "Values to keep". The step is labelled Outcome unknown and is not retried automatically.
Input shows the request exactly as sent.
Output shows the response, so you can see the real field name.

#3. Follow the data

Steps after the failure show Skipped with Not run: an earlier step failed.
Click an arrow: No data moved: the earlier step did not complete on this path.
Press Replay and step through the events to see the order things happened.

#4. Fix and rerun

Back in the editor, the failed card and the step panel's In the last run section show the same error.
Optionally use Ask an agent why it failed at the bottom of the step panel. Review its suggestion, Apply it or fix it yourself.
Set the path back to nbHits, Save, and Run again.

Expected: the run completes. The old run still shows its version and failure.

#5. Agent failures and retries

For an Agent step with a JSON reply, a reply missing a declared field fails with The reply did not match the fields this step asks for: …. With Attempts above 1, the step retries; the inspector shows Attempt 1, Attempt 2 and Compare, and the card says Succeeded after 1 failed attempt.

#6. Interrupted runs

Close LoCrew while a run is going, then reopen it. The run is Interrupted: LoCrew stopped while this run was in progress. Resume it to re-run the interrupted steps. Press Resume. Only the cut-off steps run again; completed steps keep their results.

#What the failure labels mean

Label	Retry helps?
Failed	Yes
Ran out of time	Maybe; raise the time limit
Cannot succeed as it is	No; fix the cause
Outcome unknown	Check first; it may have taken effect
Stopped	It was cancelled