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

Pre-Handoff Validation (Hard Stop)

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

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