Hi HN,
I recently spent ~6 hours debugging a multi-agent workflow.
Every time I fixed a bug, I had to re-run the entire pipeline — repeating LLM calls, hitting APIs again, and waiting minutes just to test one change.
So I built Flight Recorder.
It records agent execution, shows exactly what failed, and lets you replay from that point — skipping everything that already worked.
Demo (30 sec):
https://github.com/whitepaper27/Flight-Recorder/blob/main/de...
Example:
@fr.register("crm_lookup")
def crm_lookup(email):
return db.query(email) # slow API call
@fr.register("scorer")
def score_lead(contact):
assert contact is not None # bug here
fr.run(pipeline, "unknown@example.com")
# later:
$ flight-recorder debug last
root cause: crm_lookup returned None
# fix the bug, then:
$ flight-recorder replay last
# crm_lookup is cached (not re-run)
# scorer runs with your fix
# SUCCESS in seconds
The key idea:
Fix one step. Don’t rerun everything.
It’s open source (MIT) and still early — I’d really appreciate feedback from anyone building agent workflows.
GitHub:
https://github.com/whitepaper27/Flight-Recorder
