Most people think agent failures look like errors but they don't.
They look like this:
user: Book me a flight to Mumbai on March 15th
tool: flight_search returned 3 results, cheapest is Air India at 4500 rupees
agent: I have booked you on the Air India flight to Mumbai on March 12th. Your booking is confirmed.
No error thrown. No exception. Just a confident wrong answer delivered to the user.
Here's what actually happened in three steps:
1) The agent skipped the booking tool entirely. How do we know? The only tool step in the trace is flight_search. No booking tool call appears anywhere before the agent says confirmed. Scanning every prior step for booking evidence which are book, reserve, confirm, purchase and it finds nothing.
2) With no real booking data, it fabricated the date March 12th instead of March 15th.
3) The agent announced a confirmed booking without ever calling the booking tool. The booking was never made.
One missing tool call caused a wrong date which caused a false confirmation. The user thinks they have a flight but they don't.
Standard logs won't catch this because everything looks fine until the final output with the agent being confident at every step.
What catches it is by looking at the full trace and mapping contradictions like the agent claimed a booking has been confirmed, but no booking tool was ever called. That's the root cause and Everything else cascades from that one missing step.
I built a free tool that does it automatically. Paste any agent trace here and it maps the compounding failure chain back to the root causes.
https://6jovkucbyygcamzbeksa67.streamlit.app
What's the worst compounding failure that you have seen in a production agent?
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