I've been running an AI agent that makes tool calls to various APIs, and I added a logging layer to capture exactly what was being sent vs. what the tools expected. Over 84 tool calls in 72 hours, 31 of them (37%) had parameter mismatches — and not a single one raised an error. The tools accepted the wrong parameters and returned plausible-looking but incorrect output. Here are the 4 failure categories I found: 1. Timestamp vs Duration — The agent passed a Unix timestamp where the API expected a duration string like "24h". The API silently interpreted it as a duration, returning results for a completely different time window than intended. 2. Inclusive vs Exclusive Range — The agent sent end=100 meaning "up to and including 100," but the API interpreted it as exclusive, missing the boundar...
