Diagnose Skill

Purpose

Investigation skill for bugs where the root cause is unknown. When you don't know why something is broken — just that it is — use /diagnose before reaching for /fix.

Key mechanism: spawns a fresh-context debugger subagent (Task tool) alongside a /review solve companion analysis. The main agent orchestrates, stays clean, and synthesizes results. Debug sessions persist in .claude/debug/<slug>.md so they survive context compaction and can be resumed.

Not for: applying a fix you already understand (use /fix), or quick one-line patches (use /quick).

When to Use