Code Graph RAG — C++ Implementation

A C++ replication of the code-graph-rag-mcp TypeScript project, built as a learning exercise.

🎯 What Is This?

An MCP server that:

1. Parses source code into an Abstract Syntax Tree (AST) using Tree-Sitter
2. Stores code entities (functions, classes) and relationships (calls, imports) in a SQLite graph database
3. Generates vector embeddings for semantic code search
4. Serves 26 tools to AI assistants (Claude, Gemini) via the MCP protocol

📁 Project Structure

code-graph-rag-cpp/
├── CMakeLists.txt              ← Open this in Visual Studio
├── config/default.yaml         ← Application settings
├── examples/hello.py           ← Test files for parser
├── src/
│   ├── main.cpp                ← Entry point (milestone tests)
│   ├── types/                  ← ⭐ START HERE: Data models
│   │   ├── entity_types.h      ← Enums (EntityType, RelationType)
│   │   ├── storage_types.h     ← Core structs (Entity, Relationship)
│   │   ├── parser_types.h      ← Parser output types
│   │   ├── agent_types.h       ← Agent system types
│   │   ├── semantic_types.h    ← Embedding/vector types
│   │   └── error_types.h       ← Custom exceptions
│   ├── config/                 ← YAML config loading
│   ├── storage/                ← SQLite graph database
│   │   ├── sqlite_manager.*    ← Connection + pragmas
│   │   ├── schema_migrations.* ← Table creation
│   │   ├── graph_storage.*     ← CRUD operations (Facade)
│   │   ├── batch_operations.*  ← Bulk inserts
│   │   └── cache_manager.h     ← LRU cache (complete!)
│   ├── parsers/                ← [TODO] Tree-sitter parsing
│   ├── agents/                 ← [TODO] Multi-agent system
│   ├── semantic/               ← [TODO] Embedding + vector search
│   ├── core/                   ← [TODO] Knowledge bus
│   └── tools/                  ← [TODO] MCP tool implementations
└── tests/                      ← [TODO] Unit tests

🚀 How to Build (Visual Studio Community)

Prerequisites

1. Visual Studio Community 2022 with "Desktop development with C++" workload
2. vcpkg for dependency management

Install Dependencies

# Install vcpkg (one-time setup)
git clone https://github.com/microsoft/vcpkg.git
cd vcpkg
.\bootstrap-vcpkg.bat

# Install project dependencies
.\vcpkg install sqlite3 yaml-cpp nlohmann-json gtest

Open in Visual Studio

1. Open Visual Studio
2. File → Open → CMake...
3. Navigate to CMakeLists.txt in this folder
4. Visual Studio auto-generates the solution
5. Build → Build All (Ctrl+Shift+B)
6. Debug → Start Debugging (F5)

🏗️ Build Order (Follow This Exactly)

Phase	Milestone	What to Implement
1	✅ Types compile	src/types/ — Already done!
2	Config loads	src/config/ — Load YAML settings
3	DB works	src/storage/ — SQLite CRUD
4	Parser works	src/parsers/ — Tree-sitter AST
5	Agents run	src/agents/ — Task delegation
6	Search works	src/semantic/ — Embeddings
7	Server runs	main.cpp — MCP JSON-RPC

🐛 Debugging Tips

• F9: Set breakpoint
• F5: Start debugging
• F10: Step over (execute line)
• F11: Step into (dive into function)
• Shift+F11: Step out
• Watch Window: Add variables to monitor
• DB Browser for SQLite: Open .db files to inspect tables