Repo Analysis

Repository Analysis Skill

✨ SKILL ACTIVATED: repo-analysis
   Purpose: Deep repository analysis methodology
   Functionality: Structure discovery, tech stack detection, pattern recognition, dependency analysis
   Output: Structured analysis report with actionable insights
   Scope: Portable across VS Code, CLI, Claude, Cursor, and compatible agents

Purpose

Provides systematic methodology for comprehensive repository analysis including structure mapping, dependency identification, pattern recognition, and impact assessment. Essential for informed decision-making before making changes.

When to Use This Skill

• Analyzing repositories for Copilot customization opportunities
• Understanding codebase architecture before refactoring
• Assessing impact of proposed changes
• Identifying existing patterns and conventions
• Planning new feature implementation
• Evaluating tech stack and dependencies

Analysis Framework

Phase 1: Structure Discovery

Objective: Map repository organization and key components

Steps:

1. Root Analysis

   • Identify project type (API, CLI, library, web app)
   • Locate configuration files (package.json, tsconfig.json, etc.)
   • Scan for monorepo vs single-project structure

2. Directory Mapping

   • Source code organization (src/, lib/, app/)
   • Test structure (tests/, tests, spec/)
   • Documentation location (docs/, README files)
   • Build artifacts and configuration

3. File Patterns

   • Naming conventions (kebab-case, PascalCase, snake_case)
   • File organization by feature vs by type
   • Module structure and imports

Output: Repository structure map with key directories and file patterns

Phase 2: Tech Stack Detection

Objective: Identify languages, frameworks, and tools

Detection Criteria:

Languages:
  - File extensions (.ts, .py, .rs, .go, .cs)
  - Shebang lines in scripts
  - Language-specific patterns

Frameworks:
  - Package dependencies (package.json, requirements.txt, Cargo.toml)
  - Import statements (import React, from flask, use actix_web)
  - Configuration files (next.config.js, vue.config.js)

Tools:
  - Build systems (webpack, vite, cargo, dotnet)
  - Test frameworks (jest, pytest, xunit)
  - Linters/formatters (eslint, black, rustfmt)

Output: Complete tech stack inventory with versions

Phase 2b: Standards Resolution

Objective: Discover and match enterprise coding standards

Steps:

1. Scan .github/standards/ recursively for *.md files (skip README.md)
2. Parse YAML frontmatter from each file — extract name, technologies, scope, priority
3. Match standards against detected tech stack:
   • Collect all scope: always standards
   • For scope: tech-match, compare technologies[] against detected stack (case-insensitive)
4. Sort matched standards by priority (high > medium > low)
5. Bundle as standardsContext for downstream agents

Edge Cases:

• Empty or missing .github/standards/ → skip this phase, proceed normally
• No technology matches → only scope: always standards apply
• Conflicting guidance → higher-priority standard wins

Output: Matched standards summary with key principles per standard

Reference: Standards.instructions.md

Phase 3: Pattern Recognition

Objective: Identify architectural patterns and conventions

Pattern Categories:

1. Architectural Patterns

   • MVC, MVP, MVVM structure
   • Repository pattern usage
   • Dependency injection
   • Middleware chains
   • Plugin/extension systems

2. Code Organization

   • Feature folders vs layer folders
   • Module boundaries
   • Separation of concerns
   • Code splitting strategies

3. Naming Conventions

   • Function naming (camelCase, snake_case, descriptive)
   • Variable naming patterns
   • File naming standards
   • API endpoint naming

4. Testing Patterns

   • Test file co-location vs separation
   • Unit vs integration test organization
   • Test naming conventions
   • Mock/stub patterns

Output: Pattern catalog with examples from codebase

Phase 4: Dependency Analysis

Objective: Map internal and external dependencies

Internal Dependencies:

• Module import chains
• Cross-feature references
• Shared utility usage
• Common types/interfaces

External Dependencies:

• NPM/pip/cargo packages
• Version constraints
• Deprecated dependencies
• Security vulnerabilities

Dependency Mapping:

Component A
  ├─→ Internal: UtilityB, ServiceC
  └─→ External: express@4.18, axios@1.6

Component B
  ├─→ Internal: SharedTypes, ConfigD
  └─→ External: lodash@4.17, winston@3.11

Output: Dependency graph with risk assessment

Phase 5: Impact Assessment

Objective: Evaluate change risk and affected areas

Impact Analysis:

1. Direct Impact

   • Files that would be modified
   • Functions/classes that would change
   • API contracts affected

2. Indirect Impact

   • Files that import changed modules
   • Tests that cover changed code
   • Documentation requiring updates

3. Risk Levels

   LOW: Isolated changes, good test coverage
   MEDIUM: Cross-module changes, partial test coverage
   HIGH: Core infrastructure, API contracts, low test coverage
   

Risk Factors:

• Number of dependents
• Test coverage percentage
• Public API surface changes
• Breaking change potential
• Backward compatibility concerns

Output: Impact report with risk classification

Phase 6: Existing Customization Audit

Objective: Identify current Copilot customizations

Discovery:

Check for:
  .github/agents/*.agent.md
  .github/instructions/*.instructions.md
  .github/prompts/*.prompt.md
  .github/skills/*/SKILL.md
  AGENTS.md

Asset Inventory:

• Count of each asset type
• Coverage analysis (what domains are customized)
• Gaps identification (what's missing)
• Quality assessment (schema compliance, completeness)

Output: Customization state report with recommendations

Analysis Checklist

Use this checklist for comprehensive analysis:

• Structure

  • Project type identified
  • Directory structure mapped
  • Key files located
  • File naming patterns documented

• Tech Stack

  • Primary languages detected
  • Frameworks identified
  • Build tools documented
  • Dependencies inventoried

• Patterns

  • Architectural patterns recognized
  • Code organization understood
  • Naming conventions documented
  • Testing patterns identified

• Dependencies

  • Internal dependencies mapped
  • External packages listed
  • Version constraints noted
  • Security issues flagged

• Impact

  • Change scope defined
  • Affected files listed
  • Risk level assessed
  • Mitigation strategies planned

• Standards

  • Enterprise standards matched (if present)
  • Always-apply standards collected
  • Tech-match standards resolved against detected stack

• Customization

  • Existing assets inventoried
  • Coverage gaps identified
  • Quality issues noted
  • Enhancement opportunities listed

Output Template

## Repository Analysis Report

### Project Overview
- **Type**: [API/CLI/Web App/Library]
- **Primary Languages**: [List]
- **Key Frameworks**: [List with versions]
- **Build System**: [Tool and configuration]

### Structure
**Source Organization**:
- [Description of src/ structure]

**Test Organization**:
- [Description of test structure]

### Tech Stack
| Category | Technology | Version | Notes |
|----------|-----------|---------|-------|
| Language | TypeScript | 5.3 | Strict mode enabled |
| Framework | Express | 4.18 | RESTful API |
| Testing | Jest | 29.7 | Unit + integration |

### Patterns Identified
1. **Repository Pattern**: Data access abstraction
2. **Middleware Chain**: Request processing pipeline
3. **Dependency Injection**: Constructor-based DI

### Dependencies
**Critical Dependencies** (high usage):
- express: REST framework
- prisma: Database ORM
- zod: Runtime validation

**Risk Areas**:
- [List vulnerable or deprecated packages]

### Impact Assessment
**Proposed Change**: [Description]

**Direct Impact**:
- [Files to modify]

**Indirect Impact**:
- [Dependent files]

**Risk Level**: MEDIUM
- [Risk factors]

### Customization Status
**Existing Assets**:
- Agents: 3 (APIExpert, TestGen, Security)
- Instructions: 2 (Coding standards, API patterns)
- Prompts: 2 (Generate endpoint, Document API)
- Skills: 0

**Gaps Identified**:
- No debugging skills
- Missing deployment automation
- Security review workflows needed

### Matched Enterprise Standards
| Standard | Scope | Priority | Key Principles |
|----------|-------|----------|----------------|
| {name} | {always/tech-match} | {high/medium/low} | {summary} |

*Standards matched via Standards instruction. Principles will be integrated into generated assets.*

### Recommendations
1. [Specific recommendation]
2. [Specific recommendation]
3. [Specific recommendation]

Best Practices

Thoroughness

• Don't skip phases - complete analysis is critical
• Document patterns even if they seem obvious
• Note both good and problematic patterns

Context Gathering

• Search broadly before narrowing focus
• Follow import chains to understand dependencies
• Check git history for recent change patterns

Risk Assessment

• Be honest about risk levels
• Consider test coverage in risk evaluation
• Flag potential breaking changes early

Communication

• Use clear, structured output format
• Provide specific examples from codebase
• Include actionable recommendations

Integration with Other Skills

Downstream (feeds to):

• planning — Use analysis results to create implementation strategies
• asset-design — Inform design decisions for customization assets
• documentation — Document architecture and patterns discovered
• orchestration — Plan orchestrated systems based on complexity analysis

Typical workflow:

repo-analysis (understand codebase) ← THIS SKILL
  ↓
planning (create strategy)
  ↓
[USER APPROVAL GATE] ✋
  ↓
Implementation
  ↓
documentation (capture outcomes)

Integration benefits: Analysis output provides essential context for downstream skills, reducing redundant discovery and improving decisions.

Success Criteria

A complete repository analysis should provide:

• ✅ Clear understanding of project architecture
• ✅ Comprehensive tech stack inventory
• ✅ Documented patterns and conventions
• ✅ Dependency risk assessment
• ✅ Impact analysis for proposed changes
• ✅ Actionable recommendations

Skill Type: Analysis and Planning
Complexity: Medium
Typical Duration: 5-15 minutes (depending on repository size)
Prerequisites: Repository access, ability to search codebase

Cross-Platform: Works in VS Code, GitHub Copilot CLI, Claude, Cursor, and other Skills-compatible agents.

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