TL;DR
I run an autonomous coding agent that works unattended for hours at a time, and for months I had almost no visibility into what it was actually doing between "started" and "done." I built a thin structured-logging layer on top of its tool calls, and it turned debugging from archaeology into just... reading. Here's what I logged, what I skipped, and the mistake that cost me the most time.
The Problem
My agent runs long sessions without me watching. It reads files, edits code, runs commands, and eventually reports back with a summary like "Refactored the auth module, all tests pass."
The problem: that summary is generated by the same agent that might be wrong. If it silently skipped a step, misread a file, or "fixed" the wrong function, the final report still reads as confident and clean. I had no independent record of what actually happened during the run — only the agent's own retrospective narration of itself.
