Verify assumptions
Ask the agent to check the facts its plan relies on, like what a file contains, how a feature works, or what the data looks like, instead of guessing.
Require the agent to confirm its premises with evidence, by reading the actual code, checking real data, running commands, or consulting docs for the installed version, before acting on them. Unverified assumptions are a common source of confident but wrong changes.
Checking that the oven is actually on before you blame the recipe for raw cookies. The recipe might be fine.
Agents fill gaps with plausible guesses: that a function exists, that a field is never empty, that a setting is on. Asking them to verify turns guesses into facts and catches made-up details early.
I assumed every user has a time zone set. I checked the database: 12% don't. I'll handle the missing case instead of relying on that assumption.
Before you change anything, list the assumptions your plan depends on and verify each one against the actual code or data. Tell me which ones turned out false.
Thinking a confident explanation must be a checked one. Agents sound equally sure whether they verified or guessed. Ask what they actually looked at.