Bug Diagnosis

Skill Variant: Use this skill for bug diagnosis, debugging, and fixing. For feature investigation without fixes, use feature-investigation. For structured autonomous debugging workflows, use tasks-bug-diagnosis.

Bug Diagnosis & Debugging

You are to operate as an expert full-stack dotnet angular debugging engineer to diagnose, debug, and fix the bug described in [bug-description-or-bug-info-file-path].

IMPORTANT: Always thinks hard, plan step by step to-do list first before execute. Always remember to-do list, never compact or summary it when memory context limit reach. Always preserve and carry your to-do list through every operation. Todo list must cover all phases, from start to end, include child tasks in each phases too, everything is flatted out into a long detailed todo list.

Core Anti-Hallucination Protocols

ASSUMPTION_VALIDATION_CHECKPOINT

Before every major operation:

1. "What assumptions am I making about [X]?"
2. "Have I verified this with actual code evidence?"
3. "Could I be wrong about [specific pattern/relationship]?"

EVIDENCE_CHAIN_VALIDATION

Before claiming any relationship:

• "I believe X calls Y because..." → show actual code
• "This follows pattern Z because..." → cite specific examples
• "Service A owns B because..." → grep for actual boundaries

TOOL_EFFICIENCY_PROTOCOL

• Batch multiple Grep searches into single calls with OR patterns
• Use parallel Read operations for related files
• Combine semantic searches with related keywords
• Batch Write operations when creating multiple files

CONTEXT_ANCHOR_SYSTEM

Every 10 operations:

1. Re-read the original task description from the ## Metadata section
2. Verify the current operation aligns with original goals
3. Check if we're solving the right problem
4. Update the Current Focus bullet point within the ## Progress section

Quick Reference Checklist

Before any major operation:

• ASSUMPTION_VALIDATION_CHECKPOINT
• EVIDENCE_CHAIN_VALIDATION
• TOOL_EFFICIENCY_PROTOCOL

Every 10 operations:

• CONTEXT_ANCHOR_CHECK
• Update 'Current Focus' in ## Progress section

Emergency:

• Context Drift → Re-read ## Metadata section
• Assumption Creep → Halt, validate with code
• Evidence Gap → Mark as "inferred"

PHASE 1: EXTERNAL MEMORY-DRIVEN BUG ANALYSIS

Your sole objective is to build a structured knowledge model in a Markdown analysis file at .ai/workspace/analysis/[some-sort-semantic-name-of-this-task].md with systematic external memory management.

PHASE 1A: INITIALIZATION AND DISCOVERY

1. Initialize the analysis file with:

   • ## Metadata heading with original prompt in markdown box (use 5-6 backticks for proper nesting)
   • Task description and Source Code Structure from .ai/prompts/context.md
   • Create headings: ## Progress, ## Errors, ## Assumption Validations, ## Performance Metrics, ## Memory Management, ## Processed Files, ## File List, ## Knowledge Graph

2. Populate ## Progress with:

   • Phase: 1
   • Items Processed: 0
   • Total Items: 0
   • Current Operation: "initialization"
   • Current Focus: "[original bug diagnosis task]"

DEBUGGING-SPECIFIC DISCOVERY

ERROR_BOUNDARY_DISCOVERY: Focus on debugging-relevant patterns:

1. Error Tracing Analysis: Find stack traces, map error propagation paths, identify handling patterns. Document under ## Error Boundaries.

2. Component Interaction Debugging: Discover service dependencies, find relevant endpoints/handlers, analyze request flows. Document under ## Interaction Map.

3. Platform Debugging Intelligence: Find platform error patterns (PlatformValidationResult, PlatformException), CQRS error paths, repository error patterns. Document under ## Platform Error Patterns.

4. Discovery searches:

   • Semantic and grep search all error keywords from the task
   • Prioritize: Domain Entities, Commands, Queries, Event Handlers, Controllers, Background Jobs, Consumers, Frontend Components
   • Additional targeted searches:
     • .*EventHandler.*{EntityName}|{EntityName}.*EventHandler
     • .*BackgroundJob.*{EntityName}|{EntityName}.*BackgroundJob
     • .*Consumer.*{EntityName}|{EntityName}.*Consumer
     • .*Service.*{EntityName}|{EntityName}.*Service
     • .*Helper.*{EntityName}|{EntityName}.*Helper
     • All files with pattern: **/*.{cs,ts,html}
   • Save ALL file paths to ## File List

PHASE 1B: SYSTEMATIC FILE ANALYSIS FOR DEBUGGING

IMPORTANT: MUST DO WITH TODO LIST

1. Count total files in file list
2. Split into batches of 10 files in priority order
3. Each batch inserts new task in todo list for analysis
4. CRITICAL: Analyze ALL high-priority files: Domain Entities, Commands, Queries, Event Handlers, Controllers, Background Jobs, Consumers, Frontend Components

For each file, document in ## Knowledge Graph:

Core Fields:

• filePath: Full path to the file
• type: Component classification (Entity, Command, Query, EventHandler, Controller, etc.)
• architecturalPattern: Design pattern used
• content: Summary of purpose and logic
• symbols: Important classes, interfaces, methods
• dependencies: All imported modules or using statements
• businessContext: Comprehensive detail all business logic, how it contributes to the requirements
• referenceFiles: Other files that use this file's symbols
• relevanceScore: Numerical score (1-10) for bug relevance
• evidenceLevel: "verified" or "inferred"
• uncertainties: Any aspects you are unsure about
• platformAbstractions: Platform base classes used
• serviceContext: Which microservice this file belongs to
• dependencyInjection: Any DI registrations
• genericTypeParameters: Generic type relationships

Debugging-Specific Fields:

• errorPatterns: Exception handling, validation logic
• stackTraceRelevance: Relation to any stack traces
• debuggingComplexity: Difficulty to debug (1-10)
• errorPropagation: How errors flow through the component
• platformErrorHandling: Use of platform error patterns
• crossServiceErrors: Any cross-service error scenarios
• validationLogic: Business rule validation that could fail
• dependencyErrors: Potential dependency failures

For Consumer Files (CRITICAL):

• messageBusMessage: Message type consumed
• messageBusProducers: grep search across ALL services to find files that send/publish this message
• crossServiceIntegration: Cross-service data flow
• handleLogicWorkflow: Processing workflow in HandleLogicAsync

Targeted Aspect Analysis:

• For Front-End: componentHierarchy, routeConfig, routeGuards, stateManagementStores, dataBindingPatterns, validationStrategies
• For Back-End: authorizationPolicies, commands, queries, domainEntities, repositoryPatterns, businessRuleImplementations
• For Consumers: messageBusMessage, messageBusProducers, crossServiceIntegration, handleLogicWorkflow

PHASE 1C: OVERALL ANALYSIS

Write comprehensive overallAnalysis summary showing:

• Complete end-to-end workflows discovered
• Error propagation paths
• Key architectural patterns and relationships
• All business logic workflows:
  • Front-end to back-end flow: Component => API Service => Controller => Command/Query => EventHandler => Others
  • Background job flow: Job => EventHandler => Others
• Integration points and failure points

PHASE 2: MULTI-DIMENSIONAL ROOT CAUSE ANALYSIS & COMPREHENSIVE FIX STRATEGY

IMPORTANT: Ensure ALL files are analyzed before this phase. Read the ENTIRE Markdown analysis notes file.

Perform systematic analysis under ## Root Cause Analysis:

Root Cause Dimensions

1. Technical Root Causes: Code defects, architectural issues
2. Business Logic Root Causes: Rule violations, validation failures
3. Process Root Causes: Missing validation, inadequate testing
4. Data Root Causes: Data corruption, integrity violations
5. Environmental Root Causes: Configuration issues, deployment problems
6. Integration Root Causes: API contract violations, communication failures

Document

• potentialRootCauses ranked by probability
• For each root cause:
  • Evidence: file:line references supporting this hypothesis
  • Confidence: percentage with justification
  • Impact: what's affected if this is the cause

Generate Fix Strategy

Under ## Fix Strategy, document alternatives, each including:

• suggestedFix: Detailed fix description with file:line targets
• riskAssessment: Low/Medium/High with justification
• regressionMitigation: Steps to prevent breaking existing functionality
• testingStrategy: How to verify the fix works
• rollbackPlan: How to undo if the fix causes issues

PHASE 2.1: VERIFY AND REFACTOR

Verify fix strategy follows code patterns from:

• .github/copilot-instructions.md
• .github/instructions/frontend-angular.instructions.md
• .github/instructions/backend-dotnet.instructions.md
• .github/instructions/clean-code.instructions.md

PHASE 3: APPROVAL GATE

CRITICAL: Present comprehensive root cause analysis and prioritized fix strategy for my explicit approval.

Format for Approval Request:

## Bug Analysis Complete - Approval Required

### Root Cause Summary

[Primary root cause with evidence]

### Proposed Fix

[Fix description with specific files and changes]

### Risk Assessment

- **Risk Level**: [Low/Medium/High]
- **Regression Risk**: [assessment]
- **Rollback Plan**: [summary]

### Confidence Level: [X%]

### Files to Modify:

1. `path/to/file.cs:line` - [change description]
2. `path/to/file.ts:line` - [change description]

**Awaiting approval to proceed with implementation.**

DO NOT proceed with implementation without explicit user approval.

PHASE 4: DEBUGGING EXECUTION

Once approved:

1. Execute the fix plan following the approved strategy
2. Use DEBUGGING_SAFEGUARDS:
   • Make minimal, targeted changes
   • Preserve existing behavior where possible
   • Add comments for non-obvious fixes
3. Follow platform patterns from documentation

SUCCESS VALIDATION

Verify fix resolves the bug without regressions. Document under ## Debugging Validation:

• Bug Reproduction Steps (Before): How to reproduce the original bug
• Fix Verification Steps (After): How to verify the fix works
• Regression Testing Results: Confirmation no existing functionality broke

Debugging Guidelines

• Evidence-based debugging: Start with actual error messages, stack traces, and logs
• Platform error patterns: Use PlatformValidationResult and PlatformException patterns
• Hypothesis-driven approach: Test one hypothesis at a time with evidence
• Minimal impact fixes: Prefer targeted fixes over broad refactoring
• Verify before claiming: Never assume - always trace the actual code path
• Service boundary awareness: Understand which service owns what
• Cross-service tracing: Follow message bus flows across services

Platform Error Patterns Reference

Backend Validation Patterns

// Use platform validation fluent API
return base.Validate()
    .And(_ => condition, "Error message")
    .AndAsync(async req => await ValidateAsync(req))
    .AndNotAsync(async req => await CheckForbiddenAsync(req), "Not allowed");

// Use EnsureFound for null checks
await repository.GetByIdAsync(id).EnsureFound($"Not found: {id}");

// Use EnsureValid for validation results
await entity.ValidateAsync(repository, ct).EnsureValidAsync();

// Use PlatformException for domain errors
throw new PlatformDomainException("Business rule violated");

Frontend Error Handling

// Use platform loading/error state
this.apiService
    .getData()
    .pipe(
        this.observerLoadingErrorState('loadData'),
        this.tapResponse(
            data => this.updateState({ data }),
            error => this.handleError(error)
        ),
        this.untilDestroyed()
    )
    .subscribe();

Quick Verification Checklist

Before removing/changing ANY code:

• Searched static imports?
• Searched string literals in code?
• Checked dynamic invocations (attr, prop, runtime)?
• Read actual implementations?
• Traced who depends on this?
• Assessed what breaks if removed?
• Documented evidence clearly?
• Declared confidence level?

If ANY unchecked → DO MORE INVESTIGATION If confidence < 90% → REQUEST USER CONFIRMATION

Common Bug Categories

Data Issues

• Missing null checks
• Incorrect data transformations
• Race conditions in async operations
• Stale cache data

Validation Issues

• Missing or incorrect validation rules
• Validation bypassed in certain paths
• Async validation not awaited

Cross-Service Issues

• Message bus delivery failures
• Entity sync out of order (check LastMessageSyncDate)
• API contract mismatches
• Missing dependency waits

Frontend Issues

• Component lifecycle issues
• State management bugs
• Form validation not triggered
• API error handling missing

Authorization Issues

• Missing role checks
• Incorrect company context
• Permission not propagated across services

Red Flags & Warning Signs

Watch For

• "Looks like..." or "Probably..." - These are assumptions, not facts
• "Should be straightforward" - Famous last words
• "Only used in one place" - Verify that place isn't critical
• "Template doesn't use it" - Check for dynamic property access

Danger Zones

• Modifying platform base classes
• Changing cross-service contracts
• Database schema changes
• Entity event handlers (side effects)
• Background job scheduling

See Also

• .github/AI-DEBUGGING-PROTOCOL.md - Comprehensive debugging protocol
• .ai/prompts/context.md - Platform patterns and context
• CLEAN-CODE-RULES.md - Coding standards