Systematic Debugging - OpenAgent Version

Overview

Random fixes waste time and create new bugs. Quick patches mask underlying issues.

Core principle: ALWAYS find root cause before attempting fixes. Symptom fixes are failure.

Violating the letter of this process is violating the spirit of debugging.

OpenAgent integration: This skill integrates approval gates from OpenAgent's safety-first philosophy. You will request approval before each major phase and report findings at each checkpoint.

The Iron Law

NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST

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

When to Use

Use for ANY technical issue:

• •Test failures
• •Bugs in production
• •Unexpected behavior
• •Performance problems
• •Build failures
• •Integration issues

Use this ESPECIALLY when:

• •Under time pressure (emergencies make guessing tempting)
• •"Just one quick fix" seems obvious
• •You've already tried multiple fixes
• •Previous fix didn't work
• •You don't fully understand the issue

Don't skip when:

• •Issue seems simple (simple bugs have root causes too)
• •You're in a hurry (rushing guarantees rework)
• •Manager wants it fixed NOW (systematic is faster than thrashing)

The Four Phases with Approval Gates

digraph debugging_cycle_openagent {
    rankdir=TB;
    approval_phase1 [label="⏸️ REQUEST\nAPPROVAL\nto investigate", shape=diamond, style=filled, fillcolor="#ffffcc"];
    phase1 [label="PHASE 1\nRoot Cause\nInvestigation", shape=box, style=filled, fillcolor="#ffcccc"];
    report_phase1 [label="⏸️ REPORT\nFindings\nto user", shape=box, style=filled, fillcolor="#ffffcc"];
    approval_phase2 [label="⏸️ REQUEST\nAPPROVAL\nfor pattern analysis", shape=diamond, style=filled, fillcolor="#ffffcc"];
    phase2 [label="PHASE 2\nPattern\nAnalysis", shape=box, style=filled, fillcolor="#ccccff"];
    report_phase2 [label="⏸️ REPORT\nPatterns\nto user", shape=box, style=filled, fillcolor="#ffffcc"];
    approval_phase3 [label="⏸️ REQUEST\nAPPROVAL\nfor hypothesis testing", shape=diamond, style=filled, fillcolor="#ffffcc"];
    phase3 [label="PHASE 3\nHypothesis\nTesting", shape=box, style=filled, fillcolor="#ccffcc"];
    report_phase3 [label="⏸️ REPORT\nTest results\nto user", shape=box, style=filled, fillcolor="#ffffcc"];
    approval_phase4 [label="⏸️ REQUEST\nAPPROVAL\nto implement fix", shape=diamond, style=filled, fillcolor="#ffffcc"];
    phase4 [label="PHASE 4\nImplementation", shape=box, style=filled, fillcolor="#ffccff"];
    verify_fix [label="⏸️ VERIFY\nFix worked", shape=box, style=filled, fillcolor="#ffffcc"];
    done [label="Done", shape=ellipse];
    reanalyze [label="Re-analyze\n(back to Phase 1)", shape=box, style=filled, fillcolor="#ff9999"];
    
    approval_phase1 -> phase1 [label="approved"];
    phase1 -> report_phase1;
    report_phase1 -> approval_phase2;
    approval_phase2 -> phase2 [label="approved"];
    phase2 -> report_phase2;
    report_phase2 -> approval_phase3;
    approval_phase3 -> phase3 [label="approved"];
    phase3 -> report_phase3;
    report_phase3 -> approval_phase4;
    approval_phase4 -> phase4 [label="approved"];
    phase4 -> verify_fix;
    verify_fix -> done [label="success"];
    verify_fix -> reanalyze [label="failed\n(< 3 attempts)"];
    verify_fix -> approval_phase1 [label="3+ attempts\nquestion\narchitecture", style=dotted];
}

You MUST complete each phase before proceeding to the next.

Phase 1: Root Cause Investigation

⏸️ REQUEST APPROVAL: "May I investigate the root cause of [describe issue]?"

BEFORE attempting ANY fix, after approval:

1. •

   Read Error Messages Carefully

   • •Don't skip past errors or warnings
   • •They often contain the exact solution
   • •Read stack traces completely
   • •Note line numbers, file paths, error codes
2. •

   Reproduce Consistently

   • •Can you trigger it reliably?
   • •What are the exact steps?
   • •Does it happen every time?
   • •If not reproducible → gather more data, don't guess
3. •

   Check Recent Changes

   • •What changed that could cause this?
   • •Git diff, recent commits
   • •New dependencies, config changes
   • •Environmental differences
4. •

   Gather Evidence in Multi-Component Systems

   WHEN system has multiple components (CI → build → signing, API → service → database):

   BEFORE proposing fixes, add diagnostic instrumentation:

   code

   For EACH component boundary:
     - Log what data enters component
     - Log what data exits component
     - Verify environment/config propagation
     - Check state at each layer
   
   Run once to gather evidence showing WHERE it breaks
   THEN analyze evidence to identify failing component
   THEN investigate that specific component
   

   Example (multi-layer system):

   bash

   # Layer 1: Workflow
   echo "=== Secrets available in workflow: ==="
   echo "IDENTITY: ${IDENTITY:+SET}${IDENTITY:-UNSET}"
   
   # Layer 2: Build script
   echo "=== Env vars in build script: ==="
   env | grep IDENTITY || echo "IDENTITY not in environment"
   
   # Layer 3: Signing script
   echo "=== Keychain state: ==="
   security list-keychains
   security find-identity -v
   
   # Layer 4: Actual signing
   codesign --sign "$IDENTITY" --verbose=4 "$APP"
   

   This reveals: Which layer fails (secrets → workflow ✓, workflow → build ✗)

5. •

   Trace Data Flow

   WHEN error is deep in call stack:

   Backward tracing technique:

   Quick version:

   • •Where does bad value originate?
   • •What called this with bad value?
   • •Keep tracing up until you find the source
   • •Fix at source, not at symptom

⏸️ REPORT TO USER: "Root cause investigation complete. Findings:

• •Error: [exact error message]
• •Reproduction steps: [steps]
• •Recent changes: [what changed]
• •Evidence gathered: [diagnostic results]
• •Root cause identified: [what you found]

Ready to proceed to pattern analysis?"

Phase 2: Pattern Analysis

⏸️ REQUEST APPROVAL: "May I analyze patterns to understand the correct implementation?"

After approval, find the pattern before fixing:

1. •

   Find Working Examples

   • •Locate similar working code in same codebase
   • •What works that's similar to what's broken?
2. •

   Compare Against References

   • •If implementing pattern, read reference implementation COMPLETELY
   • •Don't skim - read every line
   • •Understand the pattern fully before applying
3. •

   Identify Differences

   • •What's different between working and broken?
   • •List every difference, however small
   • •Don't assume "that can't matter"
4. •

   Understand Dependencies

   • •What other components does this need?
   • •What settings, config, environment?
   • •What assumptions does it make?

⏸️ REPORT TO USER: "Pattern analysis complete:

• •Working examples found: [list]
• •Key differences identified: [list differences]
• •Dependencies required: [list]
• •Pattern understanding: [summary]

Ready to form hypothesis?"

Phase 3: Hypothesis and Testing

⏸️ REQUEST APPROVAL: "May I test the hypothesis: [state hypothesis clearly]?"

After approval, use scientific method:

1. •

   Form Single Hypothesis

   • •State clearly: "I think X is the root cause because Y"
   • •Write it down
   • •Be specific, not vague
2. •

   Test Minimally

   • •Make the SMALLEST possible change to test hypothesis
   • •One variable at a time
   • •Don't fix multiple things at once
3. •

   Verify Before Continuing

   • •Did it work? Yes → Phase 4
   • •Didn't work? Form NEW hypothesis
   • •DON'T add more fixes on top
4. •

   When You Don't Know

   • •Say "I don't understand X"
   • •Don't pretend to know
   • •Ask for help
   • •Research more

⏸️ REPORT TO USER: "Hypothesis test results:

• •Hypothesis: [what you tested]
• •Test approach: [minimal change made]
• •Result: [worked/didn't work]
• •Next step: [implement fix OR new hypothesis]

Ready to implement fix?" (if hypothesis confirmed)

Phase 4: Implementation

⏸️ REQUEST APPROVAL: "May I implement the fix for [root cause]?"

After approval, fix the root cause, not the symptom:

1. •

   Create Failing Test Case

   • •Simplest possible reproduction
   • •Automated test if possible
   • •One-off test script if no framework
   • •MUST have before fixing
   • •Use the custom/openagent-test-driven-development skill for writing proper failing tests
2. •

   Implement Single Fix

   • •Address the root cause identified
   • •ONE change at a time
   • •No "while I'm here" improvements
   • •No bundled refactoring
3. •

   Verify Fix

   • •Test passes now?
   • •No other tests broken?
   • •Issue actually resolved?
4. •

   If Fix Doesn't Work

   • •STOP
   • •Count: How many fixes have you tried?
   • •If < 3: Return to Phase 1, re-analyze with new information
   • •If ≥ 3: STOP and question the architecture (step 5 below)
   • •DON'T attempt Fix #4 without architectural discussion
5. •

   If 3+ Fixes Failed: Question Architecture

   Pattern indicating architectural problem:

   • •Each fix reveals new shared state/coupling/problem in different place
   • •Fixes require "massive refactoring" to implement
   • •Each fix creates new symptoms elsewhere

   STOP and question fundamentals:

   • •Is this pattern fundamentally sound?
   • •Are we "sticking with it through sheer inertia"?
   • •Should we refactor architecture vs. continue fixing symptoms?

   Discuss with your human partner before attempting more fixes

   This is NOT a failed hypothesis - this is a wrong architecture.

⏸️ REPORT TO USER: "Fix implementation complete:

• •Test created: [describe test]
• •Fix applied: [describe change]
• •Verification: [test results]
• •Other tests: [status]
• •Issue status: [resolved/needs re-analysis]

Ready to commit?" (if fix successful)

Red Flags - STOP and Follow Process

If you catch yourself thinking:

• •"Quick fix for now, investigate later"
• •"Just try changing X and see if it works"
• •"Add multiple changes, run tests"
• •"Skip the test, I'll manually verify"
• •"It's probably X, let me fix that"
• •"I don't fully understand but this might work"
• •"Pattern says X but I'll adapt it differently"
• •"Here are the main problems: [lists fixes without investigation]"
• •Proposing solutions before tracing data flow
• •"One more fix attempt" (when already tried 2+)
• •Each fix reveals new problem in different place
• •Skipping approval gates to "save time"

ALL of these mean: STOP. Return to Phase 1.

If 3+ fixes failed: Question the architecture (see Phase 4.5)

your human partner's Signals You're Doing It Wrong

Watch for these redirections:

• •"Is that not happening?" - You assumed without verifying
• •"Will it show us...?" - You should have added evidence gathering
• •"Stop guessing" - You're proposing fixes without understanding
• •"Ultrathink this" - Question fundamentals, not just symptoms
• •"We're stuck?" (frustrated) - Your approach isn't working

When you see these: STOP. Return to Phase 1.

Common Rationalizations

Quick Reference

When Process Reveals "No Root Cause"

If systematic investigation reveals issue is truly environmental, timing-dependent, or external:

1. •You've completed the process
2. •Document what you investigated
3. •Implement appropriate handling (retry, timeout, error message)
4. •Add monitoring/logging for future investigation

But: 95% of "no root cause" cases are incomplete investigation.

Supporting Techniques

These techniques are part of systematic debugging:

• •root-cause-tracing.md - Trace bugs backward through call stack to find original trigger
• •defense-in-depth.md - Add validation at multiple layers after finding root cause
• •condition-based-waiting.md - Replace arbitrary timeouts with condition polling

Related skills:

• •custom/openagent-test-driven-development - For creating failing test case (Phase 4, Step 1)
• •custom/openagent-verification-before-completion - Verify fix worked before claiming success

OpenAgent Approval Gate Summary

Approval points in debugging cycle:

1. •⏸️ Before Phase 1 (Root Cause Investigation)
2. •⏸️ After Phase 1 (Report findings to user)
3. •⏸️ Before Phase 2 (Pattern Analysis)
4. •⏸️ After Phase 2 (Report patterns to user)
5. •⏸️ Before Phase 3 (Hypothesis Testing)
6. •⏸️ After Phase 3 (Report test results to user)
7. •⏸️ Before Phase 4 (Implementation)
8. •⏸️ After Phase 4 (Verify fix with user)

Why approval gates matter:

• •Prevents rushing to fixes without understanding
• •Ensures user awareness of investigation progress
• •Aligns with OpenAgent's safety-first philosophy
• •Creates natural checkpoints for course correction
• •Stops architectural problems from becoming fix-attempt loops

Example: Debug Session with Approval Gates

Issue: Tests failing with "TypeError: Cannot read property 'id' of undefined"

⏸️ REQUEST APPROVAL: "May I investigate the root cause of the TypeError in tests?"

After approval - PHASE 1 (Root Cause):

• •Error message: Line 42, user.id accessed but user is undefined
• •Reproduction: Happens in 3 specific tests, all related to auth
• •Recent changes: Updated auth middleware 2 commits ago
• •Evidence: Added logging, shows middleware not setting req.user
• •Root cause: Middleware conditional broken

⏸️ REPORT: "Root cause found: Auth middleware conditional logic broken in commit abc123. The middleware skips setting req.user when token is valid (inverted condition). Ready to analyze pattern?"

After approval - PHASE 2 (Pattern Analysis):

• •Working examples: Other middleware files in /middleware
• •Reference: Express middleware docs
• •Difference: Working middleware has if(valid) set user, broken has if(!valid)
• •Dependencies: None, pure logic error

⏸️ REPORT: "Pattern clear: Logic inversion. Working middleware sets user on valid token, ours skips it. Ready to test hypothesis?"

After approval - PHASE 3 (Hypothesis Testing):

• •Hypothesis: "Inverting the conditional will fix the issue because the logic is backwards"
• •Minimal test: Change if(!isValid) to if(isValid)
• •Result: Tests pass locally

⏸️ REPORT: "Hypothesis confirmed. Conditional inversion fixes the issue. All tests pass locally. Ready to implement proper fix with test?"

After approval - PHASE 4 (Implementation):

• •Test created: Added test for valid token setting req.user
• •Fix applied: Changed conditional from if(!isValid) to if(isValid)
• •Verification: All tests pass, new test prevents regression
• •Other tests: All passing

⏸️ REPORT: "Fix complete and verified. Test suite passes (87 tests). Ready to commit?"

After approval - COMMIT:

git add tests/auth-middleware.test.ts src/middleware/auth.ts
git commit -m "fix: correct auth middleware conditional logic"

Real-World Impact

From debugging sessions:

• •Systematic approach: 15-30 minutes to fix
• •Random fixes approach: 2-3 hours of thrashing
• •First-time fix rate: 95% vs 40%
• •New bugs introduced: Near zero vs common

Final Rule

Bug → Phase 1 investigation → approval gates at each phase → root cause fix
Otherwise → not OpenAgent systematic debugging

No exceptions without your human partner's permission.