Systematic Analysis & Diagnosis

<mission_control> <objective>Perform systematic root cause investigation with evidence gathering before any fixes</objective> <success_criteria>Root cause identified with documented evidence, minimal fix applied and verified</success_criteria> </mission_control>

Overview

Systematic root cause investigation framework for debugging bugs, test failures, and unexpected behavior. Implements the 4-phase Iron Law with evidence gathering protocols and psychological pressure resistance.

Core principle: NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST

The Iron Law: Root Cause → Pattern Analysis → Hypothesis → Implementation (never skip phases)

<interaction_schema> symptom → evidence → hypothesis → test → implementation → verify </interaction_schema>

Investigation Format

<investigation_format> <investigation> <symptom> <description>[What is the observable problem?]</description> <error_messages>[Complete error text, stack traces]</error_messages> <reproduction_steps>[Exact steps to reproduce]</reproduction_steps> <frequency>[Always/Sometimes/Once]</frequency> </symptom>

<evidence> <logs>[Relevant log output]</logs> <recent_changes>[Git diff, recent commits, config changes]</recent_changes> <environment_data>[OS, versions, dependencies]</environment_data> <diagnostic_output>[Output from diagnostic commands]</diagnostic_output> </evidence> <hypothesis> <root_cause>[What is the likely root cause?]</root_cause> <reasoning>[Why does this cause the symptom?]</reasoning> <confidence>[High/Medium/Low - based on evidence]</confidence> </hypothesis> <test> <minimal_reproduction>[Smallest test to confirm hypothesis]</minimal_reproduction> <expected_result>[What should happen if hypothesis is correct]</expected_result> <actual_result>[What actually happened]</actual_result> <conclusion>[Confirmed/Rejected - hypothesis status]</conclusion> </test> </investigation> </investigation_format>

---

The Iron Law

<absolute_constraint> NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST

If you haven't completed Phase 1, you CANNOT propose fixes.

This is not a suggestion. This is a law of debugging. </absolute_constraint>

When to Use

Use when:

• Any bug or test failure occurs
• Unexpected behavior observed
• Regression testing fails
• Debugging session extends beyond 15 minutes
• Multiple failed fix attempts
• Architecture-level issues suspected

Don't use when:

• Issue is trivial and obvious (typo, missing import)
• Creative/experimental debugging
• Learning new systems (use exploratory approach)

The Four-Phase Investigation

Phase 1: Root Cause Investigation

MANDATORY FIRST STEP - Never skip to fixing

Evidence Gathering Protocol

# Multi-component diagnostic instrumentation
diagnostic_check() {
  echo "=== System State ==="
  uname -a
  node --version 2>&1 || echo "Node not found"
  npm --version 2>&1 || echo "npm not found"

  echo -e "\n=== Error Context ==="
  tail -50 error.log 2>/dev/null || echo "No error.log"

  echo -e "\n=== Recent Changes ==="
  git log --oneline -10

  echo -e "\n=== Test Output ==="
  npm test 2>&1 | tail -100

  echo -e "\n=== Build Status ==="
  npm run build 2>&1 || echo "Build failed"
}

Root Cause Discovery Techniques

1. Temporal Analysis

• When did this first occur?
• What changed between working and broken?
• Commit history analysis
• Time-based correlation

2. Backward Tracing

• Start from error symptom
• Trace call stack backward
• Identify failure point
• Find root cause upstream

3. Architecture Awareness

• 3+ failures = architectural problem, not code issue
• Systemic patterns vs isolated bugs
• Integration points as failure sources
• State management issues

4. 5 Whys Technique

For complex problems, use iterative "why" questioning to drill down:

**Problem**: [Observable symptom]

**Why 1**: [First-level cause]
→ Because [explanation]

**Why 2**: [Second-level cause]
→ Because [explanation]

**Why 3**: [Third-level cause]
→ Because [explanation]

**Why 4**: [Fourth-level cause]
→ Because [explanation]

**Why 5**: [Root cause]
→ Because [explanation]

**Root Cause**: [The fundamental issue]
**Action**: [What to fix to prevent recurrence]

Guidelines:

• Be specific - each answer should be factual and verifiable
• Avoid blame - focus on systems and processes
• Check logic - ensure each answer explains the previous level
• Stop at root cause - when you reach something actionable

Evidence Documentation

Document ALL findings:

## Root Cause Analysis

**Symptom:** [Exact error message or behavior]

**Evidence:**

1. [Source file:line] - What happened
2. [Source file:line] - Why it failed
3. [Source file:line] - Root cause

**Pattern:** [Isolated issue or systemic problem?]

Phase 2: Pattern Analysis

Question: Is this isolated or systemic?

Pattern Recognition

Isolated Patterns:

• Single component affected
• Reproducible with specific input
• No cascade effects
• Local fix sufficient

Systemic Patterns:

• Multiple components affected
• Architecture-level issue
• State management problem
• Integration failure

Decision Tree

graph TD
    A[Pattern Identified] --> B{Recurring Issue?}
    B -->|Yes| C[Systemic Problem]
    B -->|No| D[Isolated Issue]
    C --> E[Architecture Review Required]
    D --> F[Local Fix Sufficient]

Phase 3: Hypothesis Formation

MANDATORY: Single hypothesis, minimal testing

Hypothesis Criteria

Good Hypotheses:

• Based on evidence from Phase 1
• Falsifiable (can be proven wrong)
• Specific (predicts exact behavior)
• Actionable (suggests concrete fix)

Bad Hypotheses:

• Multiple competing hypotheses
• Based on assumptions, not evidence
• Too vague to test
• Confirmed without testing

Hypothesis Template

## Hypothesis

**Based on:** [Evidence from Phase 1]

**Predicts:** [Specific behavior if hypothesis is true]

**Test:** [Minimal test to verify/falsify]

**Expected Result:** [What we should see]

Phase 4: Implementation

Only after Phases 1-3 complete

Implementation Protocol

1. Implement fix based on verified hypothesis
2. Test fix with minimal test case
3. Verify no regressions with broader test suite
4. Document root cause for future reference

Fix Validation

# Minimal test to verify fix
test_fix() {
  echo "Running minimal fix verification..."
  node -e "[test code]"
  if [ $? -eq 0 ]; then
    echo "✅ Fix verified"
  else
    echo "❌ Fix failed - re-examine hypothesis"
  fi
}

Red Flags - STOP

Investigation Violations

• Skipping Phase 1 (root cause) and jumping to fixes
• Multiple competing hypotheses (choose ONE)
• Fixing without evidence-based hypothesis
• Assuming instead of testing
• Pattern denial (ignoring systemic issues)
• Starting to code before completing Phase 3

Rationalization Prevention

Excuse	Reality
"This should work"	TEST it first
"Looks correct"	Evidence needed
"Probably just a typo"	Verify root cause
"I've seen this before"	This case may differ
"Time pressure"	Fixes without root cause waste time
"Probably nothing"	Thorough investigation needed
"Just restart"	Restarts don't fix root causes

Stop Patterns

If you catch yourself:

• ✅ Fixing without root cause analysis
• ✅ Making multiple hypothesis at once
• ✅ Ignoring evidence that contradicts assumptions
• ✅ Rushing to implementation
• ✅ Denying systemic patterns

STOP and return to Phase 1.

Pressure Resistance

Common Pressure Scenarios

Time Pressure:

• "Need to deploy soon"
• "User waiting for fix"
• "Demo in 30 minutes"

Response: Root cause investigation prevents future issues. Fixes without root cause create technical debt.

Sunk Cost:

• "Already spent 2 hours debugging"
• "Almost there with current approach"
• "Can't abandon this fix attempt"

Response: Sunk cost fallacy. Return to root cause with fresh perspective.

Obvious Fix Temptation:

• "It's obviously just a missing semicolon"
• "Clearly the API is down"
• "Just need to restart"

Response: Verify with evidence. Obvious ≠ Correct.

Pressure Response Protocol

1. Acknowledge pressure
2. Return to systematic approach
3. Brief justification: "Root cause prevents recurrence"
4. Continue investigation

Evidence Gathering Templates

Bug Report Template

## Bug Analysis Report

### Symptom

[Exact error message or behavior]

### Reproducibility

- [ ] Always
- [ ] Sometimes
- [ ] Specific conditions: [list]

### Environment

- OS: [uname -a]
- Node: [node --version]
- Dependencies: [npm list]

### Timeline

- First observed: [date/time]
- Last working: [date/time]
- Changes since: [git log]

### Evidence

1. [Source:line] - [description]
2. [Source:line] - [description]

### Root Cause

[Single sentence: What actually failed?]

### Pattern

- [ ] Isolated issue
- [ ] Systemic problem

### Hypothesis

[Based on evidence, what causes this?]

### Test

[How to verify hypothesis?]

### Fix

[What changes resolve the issue?]

Test Failure Analysis

## Test Failure Analysis

### Failure Message

[Exact test output]

### Stack Trace

[Full stack trace]

### Test Code
```javascript
[Relevant test code]

Implementation

[Relevant implementation]

Root Cause

[What actually failed?]

Fix Strategy

[How to resolve?]

## Systematic vs Heuristic Debugging

### When to Use Systematic

- **Complex failures** - Multiple components
- **Recurring issues** - Happened before
- **Production bugs** - High stakes
- **Architectural problems** - 3+ failures
- **Time pressure** - Prevent future issues

### When Heuristic is OK

- **Learning new code** - Exploratory
- **Prototyping** - Experimentation
- **Trivial issues** - Obvious typos
- **Time extreme** - Emergency hotfix

**Rule:** If systematic takes >30 minutes on obvious issue, switch to heuristic. But document root cause afterward.

## Key Principles

1. **Evidence-based investigation** - Gather proof, don't assume
2. **Single hypothesis focus** - Test one thing at a time
3. **Pattern recognition** - Distinguish isolated vs systemic
4. **Architecture awareness** - 3+ failures = systemic
5. **Pressure resistance** - Systematic beats intuition under stress

**Remember:** Fixing without root cause investigation is like putting tape on a water pipe without finding the crack.

---

## References

For related diagnostic capabilities:
- **Use the skill `quality-standards`** - Unified quality validation and three-way audit

---

## Genetic Code

This component carries essential Seed System principles for context: fork isolation:

<critical_constraint>
MANDATORY: All components MUST be self-contained (zero .claude/rules dependency)
MANDATORY: Achieve 80-95% autonomy (0-5 AskUserQuestion rounds per session)
MANDATORY: Description MUST use What-When-Not format in third person
MANDATORY: No component references another component by name in description
MANDATORY: Progressive disclosure - references/ for detailed content
MANDATORY: Use XML for control (mission_control, critical_constraint), Markdown for data
No exceptions. Portability invariant must be maintained.
</critical_constraint>

**Delta Standard**: Good Component = Expert Knowledge − What Claude Already Knows

**Recognition Questions**:
- "Would Claude know this without being told?" → Delete (zero delta)
- "Can this work standalone?" → Fix if no (non-self-sufficient)
- "Did I read the actual file, or just see it in grep?" → Verify before claiming

---

## Absolute Constraints (Non-Negotiable)

<critical_constraint>
**THE IRON LAW: NO FIXES WITHOUT ROOT CAUSE INVESTIGATION**

- Complete Phase 1 (Root Cause Investigation) BEFORE proposing ANY fix
- Document symptoms, evidence, hypothesis BEFORE implementing
- Test hypothesis with minimal reproduction BEFORE full fix
- NEVER skip to Phase 4 without completing Phases 1-3

**MANDATORY: Use `<investigation>` format**

- Symptom: What is the observable problem?
- Evidence: Error messages, logs, recent changes, environment
- Hypothesis: What is the likely root cause and why?
- Test: Minimal reproduction to confirm hypothesis

**MANDATORY: One hypothesis at a time**

- Form single hypothesis based on evidence
- Test with minimal reproduction
- Confirm or reject before next hypothesis
- NEVER try multiple fixes simultaneously

**MANDATORY: Verification before claiming completion**

- Test confirms fix resolves issue
- No regressions introduced
- Edge cases considered
- Root cause documented

**MANDATORY: Question architecture after 3+ failed hypotheses**

- If 3+ hypotheses fail: STOP fixing
- Question the pattern/architecture
- Discuss with human partner
- Wrong pattern cannot be fixed by more patches

**No exceptions. Symptom patches are failure. Evidence-based investigation is mandatory.**
</critical_constraint>