I Gave Claude Code the Same Bug Report 3 Times. It Missed What a Human Would Catch in 5 Seconds.

A colleague messages you: "Your recent change is breaking the integration. The tool message storage logic fails when there are multiple tool calls in a row." They paste the exception: IntegrityError: duplicate key value violates unique constraint DETAIL: Key (request_id, message_index)=(4f62ae0f, 9) already exists. [parameters: { 'request_id': '4f62ae0f', 'message_index': 9, 'role': 'user', 'content': '...' }] A human engineer reads this and immediately thinks: "Wait — the colleague says tool messages are the problem, but the failing row has role='user'. That's not a tool message. The tool-handling logic wouldn't even run for this row." That contradiction is the entire investigation. Five seconds. Done. I ran this exact bug report through Claude Code 3 times — same codebase, same prompt, same exception. Each time with a different navigation approach (graph-guided, no map, docs-guided). Same model, clean context each time. All 3 runs missed role='user'. Then I ran the same prompt throug