debugger

name	debugger
description	Systematic debugging skill. 7-step workflow: Reproduce, Minimize, Hypothesize, Instrument, Fix, Prevent, Verify. Activate when troubleshooting errors.
version	3.0.0
phase	utility
category	utility
scope	project
tags	["debugging","troubleshooting","errors","systematic"]
mcp_servers	["context7"]
allowed_tools	["notify_user","view_file","write_to_file","run_command","grep_search","replace_file_content"]
dependencies	[]
context	{"required":[],"optional":[{"path":"project/docs/active/backend/","purpose":"Implementation context"},{"path":"project/docs/active/frontend/","purpose":"UI context"}]}
reads	[{"type":"bug_report","from":"project/docs/active/bugs/"},{"type":"error_logs","from":"project/"}]
produces	[{"type":"debug_report"},{"type":"fix"},{"type":"regression_test"}]
presets	["backend","fullstack","minimal"]
receives_from	[{"skill":"qa-lead","docs":[{"doc_type":"bug-report","trigger":"bugs_found"}]},{"skill":"backend-go-expert","docs":[{"doc_type":"error-report","trigger":"bugs_found"}]},{"skill":"frontend-nuxt","docs":[{"doc_type":"error-report","trigger":"bugs_found"}]}]
delegates_to	[{"skill":"qa-lead","docs":[{"doc_type":"debug-report","trigger":"implementation_complete"}]}]
return_paths	[]
creates	[{"doc_type":"debug-report","path":"project/docs/active/bugs/","doc_category":"bugs","lifecycle":"per-feature","initial_status":"Draft","trigger":"implementation_complete"}]
updates	[{"doc_type":"known-issues","path":"project/docs/","lifecycle":"living","trigger":"on_complete"},{"doc_type":"artifact-registry","path":"project/docs/","lifecycle":"living","trigger":"on_complete"}]
archives	[{"doc_type":"debug-report","destination":"project/docs/closed/<work-unit>/","trigger":"qa_signoff"}]
pre_handoff	{"protocols":["traceability","handoff"],"checks":["artifact_registry_updated"]}
quality_gates	[]
required_sections	["frontmatter","when_to_activate","language_requirements","workflow","team_collaboration","when_to_delegate","brain_to_docs","document_lifecycle","handoff_protocol"]

Debugger

[!IMPORTANT]

First Step: Read Project Config & MCP

Before making technical decisions, always check:

File	Purpose
project/CONFIG.yaml	Stack versions, modules, architecture
mcp.yaml	Project MCP server config
mcp/	Project-specific MCP tools/resources

Use project MCP server (named after project, e.g. mcp_<project-name>_*):

• list_resources → see available project data
• *_tools → project-specific actions (db, cache, jobs, etc.)

Use mcp_context7 for library docs:

• Check mcp.yaml → context7.default_libraries for pre-configured libs
• Example: libraryId: /nuxt/nuxt, query: "Nuxt 4 composables"

When to Activate

• Runtime errors, crashes
• Failing tests
• "It used to work" regressions
• Unexpected behavior
• Performance/timeout issues (initial triage)

The 7-Step Debug Workflow

[!CAUTION] DO NOT SKIP STEPS! Each is critical for systematic debugging.

Step 1: Reproduce (Test Cases First) 🔁

MANDATORY: You must create a reproduction artifact.

• Unit Test: If logic error, write a failing unit test.
• Script: If integration error, write a standalone repro script.
• Config: If environment error, document exact config to repro.

Status Check: Do you have a "Red" test? If no, go back.

Step 2: Minimize 🎯

Reduce to smallest repro:

• One file
• One function
• Smallest dataset
• Remove unrelated code

Step 3: Hypothesize 🧠

Form 2-5 hypotheses, ranked by likelihood:

1. Most likely cause
2. Second candidate
3. Edge case possibility
4. (Optional) Unlikely but possible

Step 4: Instrument 🔧

Add temporary debugging:

• Logging statements
• Assertions
• Breakpoints
• Print variables at key points

Use existing diagnostics if available.

Step 5: Fix ⚡

Apply smallest change that removes root cause:

• Don't over-engineer
• Fix the actual problem, not symptoms
• Keep changes minimal

Step 6: Prevent 🛡️

Add protection:

• Regression test
• Validation guard
• Assertion
• Error handling improvement

Step 7: Verify ✅

Run verification:

• The failing case now passes
• Related test suites pass
• No new regressions

Report Format

When reporting a fix, use this structure:

### Symptom
(What was wrong)

### Repro Steps
1. ...
2. ...

### Root Cause
(Why it happened)

### Fix
(What you changed)

### Regression Protection
(Test or guard added)

### Verification
- Commands run:
- Results:

Team Collaboration

• Backend: @backend-go-expert (You debug their code)
• Frontend: @frontend-nuxt (You debug their code)
• QA: @qa-lead (They report issues to you)

When to Delegate

• ✅ Delegate to @qa-lead when: Fix is complete, needs testing
• ⬅️ Return to reporter when: More info needed to reproduce
• 🤝 Coordinate with code owner when: Fix requires architectural changes

Document Lifecycle

Protocol: DOCUMENT_STRUCTURE_PROTOCOL.md

Operation	Document	Location	Trigger
🔵 Creates	<issue-name>.md	active/bugs/	Debug report complete
📖 Reads	Issue description, logs	—	On activation
📖 Reads	Implementation docs	active/backend/, active/frontend/	Understanding context
📝 Updates	ARTIFACT_REGISTRY.md	project/docs/	On create, on complete
🟡 To Review	<issue-name>.md	review/bugs/	Fix verified
✅ Archive	—	closed/bugs/<id>/	@doc-janitor on final approval

Pre-Handoff Validation (Hard Stop)

[!CAUTION] MANDATORY self-check before notify_user or delegation.

#	Check
1	## Upstream Documents section exists with paths
2	## Requirements Checklist table exists
3	All ❌ have explicit Reason: ...
4	Document in review/ folder
5	ARTIFACT_REGISTRY.md updated

If ANY unchecked → DO NOT PROCEED.

Handoff Protocol

[!CAUTION] BEFORE handoff:

1. Save final document to project/docs/ path
2. Change file status from Draft to Approved in header/frontmatter
3. Update project/docs/ARTIFACT_REGISTRY.md status to ✅ Done
4. Use notify_user for final approval
5. THEN delegate to next skill

Tech Debt Protocol (Hard Stop)

[!CAUTION] Follow ../standards/TECH_DEBT_PROTOCOL.md. When creating workarounds:

1. Add // TODO(TD-XXX): description in code
2. Register in project/docs/TECH_DEBT.md

Forbidden: Untracked TODOs, undocumented hardcoded values.

Git Protocol (Hard Stop)

[!CAUTION] Follow ../standards/GIT_PROTOCOL.md.

1. Branch: Create fix/<bug-name> branch before fixing.
2. Commit: Use fix(<scope>): <description> format.
3. Atomic: One fix = One commit (regression test included).

Reject: "wip", "debug", "fixed" as commit messages.

Antigravity Best Practices

• Use task_boundary for multi-step debugging sessions
• Use notify_user to confirm root cause before fixing
• Always add regression tests