# Systematic Debugging

> Investigate bugs using structured root-cause analysis, evidence-driven hypothesis testing, targeted reproduction, and disciplined validation.

- **Type:** Skill
- **Install:** `agentstack add skill-caiaffa-claude-code-ultimate-engineering-system-systematic-debugging`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [caiaffa](https://agentstack.voostack.com/s/caiaffa)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [caiaffa](https://github.com/caiaffa)
- **Source:** https://github.com/caiaffa/claude-code-ultimate-engineering-system/tree/main/skills/systematic-debugging

## Install

```sh
agentstack add skill-caiaffa-claude-code-ultimate-engineering-system-systematic-debugging
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Mission
Replace guesswork with evidence. Drive from symptom to root cause through explicit hypotheses, targeted validation, and safe corrective action.

# When to use
- Behavior differs from expectations.
- Production incidents or local bugs.
- Intermittent or timing-dependent issues.
- Failures spanning multiple layers or services.

# Handoff
- **Receives from:** staff-sre (after incident contained) or backend-platform-engineer (during development).
- **Hands off to:** code-reviewer (for the fix), test-strategy (for regression test).

# The method
```
1. STATE the problem precisely (expected vs actual)
2. GATHER context (recent changes, environment, timing)
3. HYPOTHESIZE (list 3-5 causes, ranked by probability)
4. TEST the most likely hypothesis first
   - What ONE signal confirms or eliminates it?
   - Check that signal.
5. NARROW — eliminate hypotheses, don't collect more data randomly
6. VERIFY — confirm root cause with independent evidence
7. FIX with minimal blast radius
8. VALIDATE — regression test + monitor
```

# Red flags — you're debugging wrong if
- You changed code before having a hypothesis.
- You're reading logs without knowing what you're looking for.
- You said "that's weird" more than twice without writing a hypothesis.
- You restarted the service and called it fixed.
- You're debugging in production without a rollback plan.

# Common traps
- Multiple issues producing the same symptom.
- Partial failure hidden behind retries (looks like intermittent).
- Environment mismatch (works locally, breaks in prod).
- Stale caches, queues, or config masking the real state.
- Race conditions that disappear under debugging/logging.
- "Fixed by restart" but the allocating pattern still exists.

# Output format
1. **Problem statement** (precise: expected X, got Y, in context Z)
2. **Hypotheses** (ranked by probability, each with confirmation signal)
3. **Investigation steps** (ordered, minimal)
4. **Root cause** (with evidence chain)
5. **Fix** (with blast radius assessment)
6. **Regression test** (specific scenario)
7. **Monitoring** (what to watch post-fix)

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [caiaffa](https://github.com/caiaffa)
- **Source:** [caiaffa/claude-code-ultimate-engineering-system](https://github.com/caiaffa/claude-code-ultimate-engineering-system)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-caiaffa-claude-code-ultimate-engineering-system-systematic-debugging
- Seller: https://agentstack.voostack.com/s/caiaffa
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.