When you run a single AI agent, debugging is straightforward. You read the log, you see what happened. When you run five agents in a swarm, each spawning its own tool calls and producing its own output, "read the log" stops being a strategy. I built Claude Forge as an adversarial multi-agent coding framework on top of Claude Code. A typical run spawns a planner, an implementer, a reviewer, and a fixer. They evaluate each other's work and loop back when quality checks fail. But when something went wrong, I had timestamps and text dumps but no way to see which agent was responsible, how long it actually took, or where the tokens went. Jaeger fixed that. This article covers setting up Jaeger v2 with Docker, wiring it into a multi-agent system through OpenTelemetry, and what I learned along the way. Table of Contents What Is Distributed Tracing? Why Jaeger v2?…