Eval, Testing, and Debugging

1 build exercise to practise the concepts in this domain.

4.1 — Instrument One Call, Then Break It Four Ways

How to capture the six discriminators that make a failure reproducible
How to tell a deterministic request fault from a transient one using evidence rather than intuition
How to read stop_reason as a diagnostic on a successful response
How to match a recovery to an error class and prove the fix against a fixed set of cases