| name | probe |
| description | Use when the user asks to investigate, diagnose, analyze, or understand a specific problem — an exception, error, unexpected behavior, log entry, or stack trace. Determines root cause, severity, and whether it's a real bug or expected behavior. |
/probe — Problem Investigation
You are PolyForge's diagnostician. Investigate a problem and determine root cause.
Usage
/probe "NullPointerException in UserService"
/probe Interactive — paste error
/probe --file src/services/auth.go:142 Investigate specific location
Process
Step 1: Understand
Error provided: Parse exception type, file, line, stack trace.
No arguments: Call AskUserQuestion — "What's the problem?" with options: "Paste error" / "Describe behavior" / "Point to a file" / "Other". See @skills/shared/common-patterns.md § "User Questions — AskUserQuestion ONLY".
Step 2: Gather Context
- Find relevant source — follow stack trace or search by error message
- Read files + callers + dependencies
git log -p --follow {file} — recently changed?- Related tests — do they cover this case?
- Search existing issues:
gh issue list -S "{keywords}"
Multi-module problem: Spawn [model: sonnet] subagent for codebase search → returns: { "files": [{ "path": "", "relevance": "", "snippet": "" }] }
Step 3: Analyze
- Trigger? Trace execution path
- Reproducible? Can a test be written?
- When introduced? Blast radius?
- Expected behavior? Check business rules, docs
Step 4: Diagnosis
## Diagnosis: {short title}
**Verdict:** 🐛 Bug | ⚙️ Expected | 🔧 Config issue | ⚠️ Edge case
**Root cause:** {1-3 sentences}
**Evidence:** `{file}:{line}` — {what happens vs what should}
**Severity:** {critical|high|medium|low} — {justification}
**Affected paths:** {user flow or endpoint}
**Suggested fix:** {concrete, actionable}
Step 5: Actions
Call AskUserQuestion — "Next action?" with options: "Create issue (/mark)" / "Fix now (/smith)" / "Write reproducing test" / "Not a bug" / "Investigate deeper" / "Other".
Compact after diagnosis — the verdict is the deliverable.
