Investigate puffin traces

Analyze a .puffin recording from an application instrumented with Puffin. Use the recording path supplied by the user. Or use the capture_profile_trace message if using the rerun MCP.

Setup

Requires the rerun CLI (Rerun 0.38 or later), Python 3.10 or later, and jq. The Python helpers use only the standard library. Set PUFFIN_SKILL_DIR to the absolute directory containing this SKILL.md. In Claude Code, you can use export PUFFIN_SKILL_DIR="${CLAUDE_SKILL_DIR}"; in other agents, resolve the directory from the installed skill location.

Dump the trace to a file and check scope registration:

rerun dump-puffin <path> > /tmp/puffin.json
jq '.scopes | length' /tmp/puffin.json