Bug Hunter

---

name: bug-hunter description: > Bug analysis, reproduction, and reporting assistant. Analyze logs, stack traces, screenshots to identify root cause. Generate structured bug reports with severity, priority, reproduction steps, and expected vs actual behavior. Use when: (1) analyzing error logs or stack traces, (2) writing bug reports, (3) triaging bugs, (4) reproducing issues, (5) root cause analysis, (6) "分析这个bug", "写bug报告", "看看这个报错", "帮我定位问题", "崩溃分析". NOT for: fixing code (use coding tools), writing test cases (use test-case-gen), or project management. metadata: openclaw: emoji: "🐛"

---

Bug Hunter

Analyze, reproduce, and report bugs with precision.

When to Use

✅ USE this skill when:

Analyzing error logs, stack traces, crash dumps

Writing structured bug reports

Triaging and prioritizing bugs

Root cause analysis from symptoms

"这个报错是什么原因" / "帮我写个bug单"

❌ DON'T use this skill when:

Fixing the code → use coding tools

Writing test cases → use test-case-gen

Testing APIs → use api-tester

Bug Report Template

When writing a bug report, use this structure:

## 🐛 Bug Report
Title: [Module] Brief description of the issue
Severity: 🔴 Critical / 🟠 Major / 🟡 Minor / 🟢 Trivial
Priority: P0-Blocker / P1-High / P2-Medium / P3-Low
Environment: OS / Browser / App Version / API Version
Reporter: 虫探 🔍
Date: YYYY-MM-DD
Description
Clear, concise description of what went wrong.
Steps to Reproduce
1. Step one (be specific: URL, button name, exact input)
2. Step two
3. Step three
Test Data
Account: xxx
Input: xxx
Expected Result
What should happen.
Actual Result
What actually happened. Include error messages verbatim.
Evidence
Screenshot: [attached]
Log snippet:
\\\
ERROR 2024-01-01 10:00:00 NullPointerException at UserService.java:42
\\\
Root Cause Analysis (if identified)
Location: file:line
Cause: description
Impact scope: what else might be affected
Suggested Fix (if obvious)
Brief suggestion for the developer.

Log Analysis

Common Error Patterns

| Pattern | Likely Cause | Action | |---------|-------------|--------| | NullPointerException | Null reference not handled | Check null checks, data flow | | ConnectionTimeout | Network/service issue | Check service health, timeout config | | OutOfMemoryError | Memory leak or insufficient heap | Analyze heap dump, check for leaks | | DeadlockException | Concurrent resource contention | Review lock ordering, transaction scope | | 401 Unauthorized | Token expired/invalid | Check auth flow, token refresh | | 429 Too Many Requests | Rate limiting | Check request frequency, add throttling | | CORS error | Cross-origin misconfiguration | Check server CORS headers |

Log Analysis Steps

1. Identify the error: Find the first error in the chain (root cause, not symptom) 2. Check timestamp: When did it first occur? Is it recurring? 3. Check context: What request/operation triggered it? 4. Check stack trace: Which module/function? What line? 5. Check related logs: What happened before the error? 6. Reproduce: Can you trigger the same error consistently?

# Quick log analysis commands
Find errors in log file
grep -n -i "error\|exception\|fatal\|failed" app.log | tail -20
Count error types
grep -oP '\w+Exception' app.log | sort | uniq -c | sort -rn
Find errors in time range
awk '/2024-01-01 10:0[0-5]/' app.log | grep -i error
Get context around an error (5 lines before and after)
grep -B5 -A5 "NullPointerException" app.log

Severity Classification

| Severity | Definition | Example | |----------|-----------|---------| | 🔴 Critical | System crash, data loss, security breach, no workaround | Payment charged but order not created | | 🟠 Major | Core feature broken, has workaround | Login fails on Chrome but works on Firefox | | 🟡 Minor | Non-core feature issue, cosmetic with functional impact | Sort order wrong on list page | | 🟢 Trivial | Cosmetic only, typo, UI alignment | Button color slightly off |

Triage Decision Matrix

                    High Impact          Low Impact
High Frequency   →  P0 Fix Now          P1 Fix Soon
Low Frequency    →  P1 Fix Soon         P2/P3 Backlog

Root Cause Categories

When analyzing root cause, classify into:

Code Defect: Logic error, missing validation, wrong algorithm

Config Error: Wrong environment config, missing feature flag

Data Issue: Corrupt data, migration problem, encoding issue

Infrastructure: Server capacity, network, third-party service

Design Flaw: Architectural issue, race condition by design

Requirement Gap: Ambiguous or missing requirement

Tips

Always include the exact error message, not a paraphrase

Screenshots > descriptions for UI bugs

Include both expected AND actual results — never skip either

Note if the bug is intermittent (include frequency)

Check if the bug exists in previous versions (regression?)

For API bugs, include the full request and response

Screenshot / UI Bug Analysis

When provided with screenshots:

1. Describe the visual issue: Element misaligned? Missing? Wrong state? 2. Identify affected component: Which UI component/area? 3. Check viewport: Is it responsive-related? Note screen size if visible. 4. Compare: Expected design vs actual rendering 5. Classify: Layout bug / Style bug / Functional state bug / Data display bug

Use the image tool to analyze screenshots, then include findings in the bug report's Evidence section.

API Error Response Analysis

When analyzing API errors:

# Save full request + response for bug report
curl -v -X POST "https://api.example.com/endpoint" \
  -H "Content-Type: application/json" \
  -d '{"key": "value"}' 2>&1 | tee /tmp/api-debug.log
Key things to capture:
- Request URL, method, headers, body
- Response status code, headers, body
- Timing information
- Any redirect chain

Common API error patterns:

| Status | Check | Likely Root Cause | |--------|-------|------------------| | 400 | Request body/params | Validation logic or schema mismatch | | 401 | Auth header | Token expired, wrong auth scheme | | 403 | Permissions | RBAC config, resource ownership | | 404 | URL path | Route not registered, wrong ID | | 409 | Business logic | Duplicate entry, state conflict | | 422 | Validation detail | Semantic validation (format, range) | | 500 | Server logs | Unhandled exception, null ref, DB error | | 502/503 | Infrastructure | Upstream service down, deployment in progress |

Always include the exact error message, not a paraphrase

Screenshots > descriptions for UI bugs

Include both expected AND actual results — never skip either

Note if the bug is intermittent (include frequency)

Check if the bug exists in previous versions (regression?)

For API bugs, include the full request and response