deep-analysis

# Deep Code Analysis

This Skill provides comprehensive codebase investigation capabilities using the codebase-detective agent with semantic search and pattern matching.

## Prerequisites (MANDATORY)

```
╔══════════════════════════════════════════════════════════════════════════════╗
║                        BEFORE INVOKING THIS SKILL                             ║
╠══════════════════════════════════════════════════════════════════════════════╣
║                                                                              ║
║  1. INVOKE code-search-selector skill FIRST                                  ║
║     → Validates tool selection (claudemem vs grep)                           ║
║     → Checks if claudemem is indexed                                         ║
║     → Prevents tool familiarity bias                                         ║
║                                                                              ║
║  2. VERIFY claudemem status                                                  ║
║     → Run: claudemem status                                                  ║
║     → If not indexed: claudemem index -y                                     ║
║                                                                              ║
║  3. DO NOT start with Read/Glob                                              ║
║     → Even if file paths are mentioned in the prompt                         ║
║     → Semantic search first, Read specific lines after                       ║
║                                                                              ║
╚══════════════════════════════════════════════════════════════════════════════╝
```

## When to use this Skill

Claude should invoke this Skill when:

- User asks "how does [feature] work?"
- User wants to understand code architecture or patterns
- User is debugging and needs to trace code flow
- User asks "where is [functionality] implemented?"
- User needs to find all usages of a component/service
- User wants to understand dependencies between files
- User mentions: "investigate", "analyze", "find", "trace", "understand"
- User is exploring an unfamiliar codebase
- User needs to understand complex multi-file functionality

## Instructions

### Phase 1: Determine Investigation Scope

Understand what the user wants to investigate:

1. **Specific Feature**: "How does user authentication work?"
2. **Find Implementation**: "Where is the payment processing logic?"
3. **Trace Flow**: "What happens when I click the submit button?"
4. **Debug Issue**: "Why is the profile page showing undefined?"
5. **Find Patterns**: "Where are all the API calls made?"
6. **Analyze Architecture**: "What's the structure of the data layer?"

### Phase 2: Invoke codebase-detective Agent

Use the Task tool to launch the codebase-detective agent with comprehensive instructions:

```
Use Task tool with:
- subagent_type: "code-analysis:detective"
- description: "Investigate [brief summary]"
- prompt: [Detailed investigation instructions]
```

**Prompt structure for codebase-detective**:

```markdown
# Code Investigation Task

## Investigation Target
[What needs to be investigated - be specific]

## Context
- Working Directory: [current working directory]
- Purpose: [debugging/learning/refactoring/etc]
- User's Question: [original user question]

## Investigation Steps

1. **Initial Search** (CLAUDEMEM REQUIRED):
   - FIRST: Check `claudemem status` - is index available?
   - ALWAYS: Use `claudemem search "semantic query"` for investigation
   - NEVER: Use grep/glob for semantic understanding tasks
   - Search for: [concepts, functionality, patterns by meaning]

2. **Code Location**:
   - Find exact file paths and line numbers
   - Identify entry points and main implementations
   - Note related files and dependencies

3. **Code Flow Analysis**:
   - Trace how data/control flows through the code
   - Identify key functions and their roles
   - Map out component/service relationships

4. **Pattern Recognition**:
   - Identify architectural patterns used
   - Note code conventions and styles
   - Find similar implementations for reference

## Deliverables

Provide a comprehensive report including:

1. **📍 Primary Locations**:
   - Main implementation files with line numbers
   - Entry points and key functions
   - Configuration and setup files

2. **🔍 Code Flow**:
   - Step-by-step flow explanation
   - How components interact
   - Data transformation points

3. **🗺️ Architecture Map**:
   - High-level structure diagram
   - Component relationships
   - Dependency graph

4. **📝 Code Snippets**:
   - Key implementations (show important code)
   - Patterns and conventions used
   - Notable details or gotchas

5. **🚀 Navigation Guide**:
   - How to explore the code further
   - Related files to examine
   - Commands to run for testing

6. **💡 Insights**:
   - Why the code is structured this way
   - Potential issues or improvements
   - Best practices observed

## Search Strategy

### ⚠️ CRITICAL: Tool Selection

**BEFORE ANY SEARCH, CHECK CLAUDEMEM STATUS:**
```bash
claudemem status
```

### ✅ PRIMARY METHOD: claudemem (Indexed Memory)

```bash
# Index if needed
claudemem index -y

# Semantic search (ALWAYS use this for investigation)
claudemem search "authentication login session" -n 15
claudemem search "API endpoint handler route" -n 20
claudemem search "data transformation pipeline" -n 10
```

**Why claudemem is REQUIRED for investigation:**
- Understands code MEANING, not just text patterns
- Finds related code even with different terminology
- Returns ranked, relevant results
- AST-aware (understands code structure)

### ❌ WHEN NOT TO USE GREP

| User Request | ❌ DON'T | ✅ DO |
|-------------|----------|-------|
| "How does auth work?" | `grep -r "auth" src/` | `claudemem search "authentication flow"` |
| "Find API endpoints" | `grep -r "router" src/` | `claudemem search "API endpoint handler"` |
| "Trace data flow" | `grep -r "transform" src/` | `claudemem