I Thought Building Agent Observability Was a Detector Problem. I Was Wrong.

When I started building agent-exec-trace, I thought I knew where the difficulty would be. OSS agent-exec-trace is an observability layer for AI agents. It instruments agent runs using OpenTelemetry-style traces, then analyzes those traces for loops, retry storms, cost spikes, hallucination patterns, and other bad runtime behavior. The goal is simple: when an agent run feels wrong, I want something better than logs and intuition to explain why.

I thought the hard part would be the detector logic.

Define the anomalies. Pick the thresholds. Wire the traces. Run the analytics. Ship the repo.

That was the clean version of the story.

The real version was uglier.