---
title: Code Knowledge Graph Explorer — 🤗 Transformers Library
emoji: 🔍
colorFrom: blue
colorTo: purple
sdk: docker
app_port: 7860
pinned: false
tags:
- building-mcp-track-enterprise
short_description: MCP server for big code — explore Transformers
---

## 👥 Team

**Team Name:** CEPIA Ionis Team

**Team Members:**
- **Laila ELKOUSSY** - [@lailaelkoussy](https://huggingface.co/lailaelkoussy) - Research Engineer, Data Scientist
- **Julien PEREZ** - [@jnm38](https://huggingface.co/jnm38) - Research Director

---

## 🎥 Demo Video

[Available in Repo](https://huggingface.co/spaces/MCP-1st-Birthday/code-knowledge-graph-explorer-transformers-library/blob/main/video-mcp-server.mp4)

---
## Social Media Post

[Available here](https://www.linkedin.com/posts/julien-perez-5492b883_mcp-aiagents-codeanalysis-activity-7400953387044990976-U8Vf/?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAABGp_AkBa02nkJK1i19ORjznehQOMgsidm8)

---


# 🎓 Code Knowledge Graph MCP Server

> **Helping LLM-based agents navigate and understand large codebases**

## 📚 What is this project?

This project provides a [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) server that transforms code repositories into navigable **knowledge graphs**. It enables Large Language Model (LLM) based agents to efficiently explore, understand, and reason about complex codebases — a critical capability for modern software engineering education and practice.

## 🔬 Use Case: EPITA Coding Courses

This project was developed with **educational applications** in mind, specifically to support **EPITA coding courses**:

### 🔍 Enhanced Code Discovery for Agents

LLM-based coding agents can use this tool to **better discover and navigate large repositories**. Instead of blindly searching through files, agents can:

- Query the knowledge graph to understand the overall architecture
- Follow relationships between modules, classes, and functions
- Identify entry points and critical code paths
- Understand how different parts of the codebase interact

### 📈 Detecting Areas for Code Improvement

For EPITA courses, this tool helps agents **identify areas where student code can be improved**:

- **Dead Code Detection**: Find unused functions, classes, or variables
- **Circular Dependencies**: Detect problematic import cycles between modules
- **Code Coupling Analysis**: Identify tightly coupled components that should be refactored
- **Missing Documentation**: Find undocumented public APIs and complex functions
- **Complexity Hotspots**: Locate chunks with many outgoing calls (high coupling)
- **Orphan Code**: Detect code that is declared but never called

### 🎓 EPITA Course Integration

- **Project Reviews**: Quickly understand student project architectures before grading
- **Automated Feedback**: Integrate with LLM tutors to provide targeted improvement suggestions
- **Code Quality Assessment**: Consistent evaluation criteria across student submissions
- **Learning Tool**: Help students navigate and understand unfamiliar codebases (e.g., open-source projects)
- **Research**: Study code organization patterns across student projects

The MCP interface makes it easy to integrate with any LLM-based tutoring or code review system used in EPITA courses.

---

### 🎯 The Problem We Solve

At **EPITA** (École pour l'informatique et les techniques avancées), students work on increasingly complex software projects throughout their curriculum. Understanding large codebases — whether their own, their teammates', or open-source libraries — is a fundamental skill for any computer science engineer.

However, LLM-based coding assistants face significant challenges when working with large repositories:

- **Context window limitations**: LLMs cannot process entire codebases at once
- **Lack of structural awareness**: Without understanding how code is organized, LLMs struggle to locate relevant files
- **Missing relationships**: Function calls, class inheritance, and module dependencies are not immediately visible
- **Inefficient search**: Simple keyword search fails to capture semantic meaning

### 💡 Our Solution: Knowledge Graphs + MCP

This project addresses these challenges by:

1. **Parsing repositories** into a structured knowledge graph (files → chunks → entities)
2. **Extracting relationships** between code elements (calls, contains, declares, imports)
3. **Indexing content** with hybrid search (semantic embeddings + keyword matching)
4. **Exposing tools via MCP** that allow LLM agents to navigate the codebase intelligently

```
┌─────────────────────────────────────────────────────────────────┐
│                     CODE REPOSITORY                              │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌──────────┐         │
│  │  File A  │  │  File B  │  │  File C  │  │  File D  │   ...   │
│  └────┬─────┘  └────┬─────┘  └────┬─────┘  └────┬─────┘         │
└───────┼─────────────┼─────────────┼─────────────┼───────────────┘
        ▼             ▼             ▼             ▼
┌─────────────────────────────────────────────────────────────────┐
│               KNOWLEDGE GRAPH CONSTRUCTION                       │
│  • AST Parsing (Python, C/C++, Java, JavaScript, Rust, HTML)    │
│  • Entity Extraction (classes, functions, variables, methods)   │
│  • Relationship Detection (calls, inheritance, imports)         │
│  • Code Chunking & Embedding (semantic vectors)                 │
└───────────────────────────────┬─────────────────────────────────┘
                                ▼
┌─────────────────────────────────────────────────────────────────┐
│                    MCP SERVER (Gradio)                           │
│  ┌─────────────┐ ┌────────────┐ ┌──────────────┐ ┌────────────┐ │
│  │search_nodes │ │go_to_def   │ │find_usages   │ │get_neighbors│ │
│  └─────────────┘ └────────────┘ └──────────────┘ └────────────┘ │
│  ┌─────────────┐ ┌────────────┐ ┌──────────────┐ ┌────────────┐ │
│  │get_file_    │ │get_related │ │find_path     │ │print_tree  │ │
│  │structure    │ │_chunks     │ │              │ │            │ │
│  └─────────────┘ └────────────┘ └──────────────┘ └────────────┘ │
└───────────────────────────────┬─────────────────────────────────┘
                                ▼
┌─────────────────────────────────────────────────────────────────┐
│                    LLM-BASED AGENT                               │
│  • Can search for relevant code using natural language          │
│  • Navigate from function calls to their definitions            │
│  • Understand the structure of files and directories            │
│  • Trace dependencies and relationships across the codebase     │
└─────────────────────────────────────────────────────────────────┘
```

## 🛠️ MCP Tools Available

The MCP server exposes the following tools for LLM agents:

| Tool                      | Description                                               |
| ------------------------- | --------------------------------------------------------- |
| `search_nodes`            | Semantic + keyword search for code chunks                 |
| `get_node_info`           | Detailed information about any node (file, chunk, entity) |
| `get_node_edges`          | Incoming and outgoing relationships of a node             |
| `go_to_definition`        | Find where a function/class/variable is declared          |
| `find_usages`             | Find all places where an entity is called/used            |
| `get_neighbors`           | Get all directly connected nodes                          |
| `get_file_structure`      | Overview of a file's chunks and entities                  |
| `get_related_chunks`      | Find chunks related by a specific relationship type       |
| `list_all_entities`       | List all tracked entities in the codebase                 |
| `get_graph_stats`         | Statistics about the knowledge graph                      |
| `find_path`               | Find shortest path between two nodes                      |
| `get_subgraph`            | Extract a subgraph around a node                          |
| `print_tree`              | Display repository structure as a tree                    |
| `diff_chunks`             | Compare content between two code chunks                   |
| `search_by_type_and_name` | Search entities by type (class, function, etc.) and name  |
| `get_chunk_context`       | Get a chunk with its surrounding context                  |

## 🌐 Supported Languages

The knowledge graph builder uses **AST-based entity extraction** for accurate parsing:

| Language              | Parser          | Entity Types                                    |
| --------------------- | --------------- | ----------------------------------------------- |
| Python                | `ast` module    | classes, functions, methods, variables, imports |
| C                     | `libclang`      | functions, structs, typedefs, variables         |
| C++                   | `libclang`      | classes, namespaces, methods, templates         |
| Java                  | `javalang`      | classes, interfaces, methods, fields            |
| JavaScript/TypeScript | `esprima`       | classes, functions, variables, imports          |
| Rust                  | `tree-sitter`   | structs, enums, traits, functions, modules      |
| HTML                  | `BeautifulSoup` | DOM elements, inline JS extraction              |

The system also detects **API endpoints** for web frameworks (FastAPI, Flask, Spring Boot, Actix-web, etc.).

## 🚀 Getting Started

### Prerequisites

- Docker & Docker Compose
- Python 3.10+ (for local development)
- CUDA-capable GPU (optional, for faster embeddings)

### Quick Start with Docker

```bash
# Start the MCP server with a sample knowledge graph
docker-compose up
```

### Building a Knowledge Graph from Your Repository

```python
from RepoKnowledgeGraphLib.RepoKnowledgeGraph import RepoKnowledgeGraph

# From a local path
kg = RepoKnowledgeGraph.from_path(
    "/path/to/your/repo",
    skip_dirs=["node_modules", ".git", "__pycache__"],
    extract_entities=True,
    index_nodes=True
)

# Save for later use
kg.save_graph_to_file("my_knowledge_graph.json")
```

### Running the MCP using Gradio

```bash
python gradio_mcp.py --graph-file my_knowledge_graph.json --host 0.0.0.0 --port 7860

```

## 📊 Interactive Explorer (Gradio UI)

The project includes a Gradio-based web interface for exploring knowledge graphs interactively:

- **Search**: Use natural language or keywords to find relevant code
- **Navigate**: Click through nodes to explore relationships  
- **Analyze**: Get statistics about code structure and dependencies
- **Visualize**: View the repository tree and entity relationships

## 📁 Data Sources

The application supports loading knowledge graphs from multiple sources:

### 1. HuggingFace Hub Dataset (Recommended for Sharing)

Load directly from a HuggingFace dataset created by the library (cf. Publishing to Huggingface Hub):

```bash
python gradio_mcp.py --host 0.0.0.0 --port 7860 --hf-dataset "username/dataset-name"
```

### 2. Local JSON File

Use a local JSON file (e.g., `multihop_knowledge_graph_with_embeddings.json`):

```bash
python gradio_mcp.py --host 0.0.0.0 --port 7860 --graph-file data/multihop_knowledge_graph_with_embeddings.json
```

### 3. Direct from Git Repository

Clone and analyze a repository on-the-fly:

```bash
python gradio_mcp.py --host 0.0.0.0 --port 7860 --repo-url "https://github.com/user/repo.git"
```

### Publishing to HuggingFace Hub

You can save an existing knowledge graph to HuggingFace Hub for sharing:

```python
from RepoKnowledgeGraphLib import RepoKnowledgeGraph

# Load from local file
kg = RepoKnowledgeGraph.load("path/to/graph.json")

# Push to HuggingFace Hub (without embeddings to reduce size)
kg.to_hf_dataset("username/my-knowledge-graph", save_embeddings=False, private=False)

# Or with embeddings (larger dataset)
kg.to_hf_dataset("username/my-knowledge-graph-with-embeddings", save_embeddings=True)
```


## 🏗️ Architecture Overview

```
root/
├── Dockerfile                  # Docker configuration
├── requirements.txt            # Python dependencies
├── RepoKnowledgeGraphLib/  # Knowledge graph implementation
│   ├── RepoKnowledgeGraph.py    # Main graph class
│   ├── KnowledgeGraphMCPServer.py # MCP server implementation
│   ├── EntityExtractor.py       # AST-based entity extraction
│   ├── CodeParser.py            # Code chunking
│   ├── CodeIndex.py             # Hybrid search (LanceDB/Weaviate)
│   ├── ModelService.py          # Embedding generation
│   └── Node.py                  # Graph node types
└── gradio_mcp_space.py              # Main Gradio web interface
```

## 📄 License

This project is developed as part of research at EPITA / Ionis Group.

## 🔗 Related Resources

- [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) - The protocol standard
- [Gradio](https://gradio.app/) - Python web interface framework with MCP support
- [LanceDB](https://lancedb.github.io/lancedb/) - Vector database for code indexing
- [Salesforce SFR-Embedding-Code](https://huggingface.co/Salesforce/SFR-Embedding-Code-400M_R) - Code embedding model

## 🆚 VS Code Integration

To use this MCP server with **GitHub Copilot** in VS Code, you need to configure an `mcp.json` file.

### Configuration File Location

Create or edit the file at `.vscode/mcp.json` in your workspace root:

```
your-workspace/
├── .vscode/
│   └── mcp.json    ← Place the configuration here
├── src/
└── ...
```

### Configuration Content

Add the following content to `.vscode/mcp.json`:

```jsonc
{
    "servers": {
        "transformers-code-graph": {
            "url": "https://mcp-1st-birthday-code-knowledge-graph-explorer-t-327857c.hf.space/gradio_api/mcp/",
            "type": "http"
        }
    },
    "inputs": []
}
```

### What This Does

- **`servers`**: Defines the MCP servers available to VS Code
- **`transformers-code-graph`**: A custom name for this server connection
- **`url`**: The endpoint of the hosted MCP server (here pointing to the HuggingFace Space)
- **`type`**: Set to `"http"` for remote HTTP-based MCP servers

### Using with Your Own Server

If you're running your own MCP server locally, update the URL accordingly:

```jsonc
{
    "servers": {
        "my-code-graph": {
            "url": "http://localhost:7860/gradio_api/mcp/",
            "type": "http"
        }
    },
    "inputs": []
}
```

Once configured, GitHub Copilot in VS Code will have access to all the knowledge graph tools (search_nodes, go_to_definition, find_usages, etc.) to help navigate and understand your codebase.