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MCP server for semantic code search with AST-aware chunking, incremental indexing, and real-time monitoring. --- idk if it works or, moreover, is actually helpful. But it is cool.

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Codebase Contextifier 9000

A Docker-based Model Context Protocol (MCP) server for semantic code search with AST-aware chunking, relationship tracking via Neo4j graph database, local LLM support, and incremental indexing.

Documentation

Table of Contents

Features

  • AST-Aware Chunking: Uses tree-sitter to respect function and class boundaries, maintaining semantic integrity
  • Relationship Tracking: Neo4j graph database tracks function calls, imports, inheritance, and dependencies across your codebase
  • External Dependency Mapping: Automatically creates placeholder nodes for external functions (WordPress, npm packages, etc.)
  • Job-Based Indexing: Background indexing with progress tracking for large codebases
  • On-Demand Container Spawning: Index any repository on your system without manual mounting
  • Multi-Repository Search: Index and search across multiple projects with a shared backend
  • Real-Time Updates: File system watcher automatically re-indexes changed files (optional)
  • Local-First: All processing happens locally using Ollama for embeddings (no data leaves your machine)
  • Polyglot Support: Supports 10+ programming languages including TypeScript, Python, PHP, Go, Rust, Java, C++, and more
  • Incremental Indexing: Merkle tree-based change detection with 80%+ cache hit rates
  • Production-Grade: Uses Qdrant vector database for sub-10ms search latency and Neo4j for relationship queries
  • Dependency Knowledge Base: Special collection for indexing WordPress plugins, Composer packages, and npm modules
  • Flexible Deployment: Per-project or centralized server deployment options
  • MCP Integration: Works with Claude Desktop, Cursor, VS Code, and other MCP-compatible tools

Architecture

┌─────────────────────────────────────────────────────────────────┐
│  MCP Client (Claude Code, Claude Desktop, Cursor, etc.)         │
└──────────────────────────────┬──────────────────────────────────┘
                               │ MCP Protocol (stdio)
                               │
┌──────────────────────────────▼──────────────────────────────────┐
│  MCP Server Container (codebase-mcp-server)                     │
│  ┌──────────────────────────────────────────────────────────┐  │
│  │  FastMCP Server - Exposes MCP Tools:                      │  │
│  │  • index_repository (spawns indexer containers)           │  │
│  │  • search_code (semantic search across all repos)         │  │
│  │  • find_usages, find_dependencies (graph queries)         │  │
│  │  • detect_dependencies, index_dependencies                │  │
│  │  • get_job_status, list_indexing_jobs, cancel_job        │  │
│  │  • get_symbols, get_indexing_status, health_check        │  │
│  └──────────────┬───────────────────────────────────────────┘  │
│                 │                                                │
│                 │ Spawns via Docker Socket                       │
│                 ▼                                                │
│  ┌─────────────────────────────────────────────────────┐       │
│  │  On-Demand Indexer Containers (ephemeral)           │       │
│  │  • Mounts any host directory                        │       │
│  │  • AST-aware chunking with tree-sitter              │       │
│  │  • Extracts relationships (CALLS, IMPORTS, etc.)    │       │
│  │  • Generates embeddings via Ollama                  │       │
│  │  • Updates shared Qdrant & Neo4j databases          │       │
│  │  • Reports progress back to MCP server              │       │
│  └──────────────────────┬──────────────────────────────┘       │
└─────────────────────────┼──────────────────────────────────────┘
                          │
          ┌───────────────┴───────────────────┐
          │                                   │
   ┌──────▼──────┐              ┌────────────▼────────┐
   │   Qdrant    │              │      Neo4j          │
   │  Container  │              │    Container        │
   │  (Vectors)  │              │  (Relationships)    │
   └──────┬──────┘              └──────┬──────────────┘
          │                            │
   ┌──────▼────────────────────────────▼───────────┐
   │  Persistent Docker Volumes:                   │
   │  • qdrant_data (vector DB)                    │
   │  • neo4j_data (graph DB)                      │
   │  • index_data (merkle trees)                  │
   │  • cache_data (embeddings cache)              │
   └───────────────────────────────────────────────┘

   ┌────────────────────────┐
   │  Ollama (Host)         │
   │  Embedding Model       │
   └────────────────────────┘

Key Architectural Features

  • Dual Database Architecture: Qdrant for semantic vector search, Neo4j for relationship graph queries
  • Container Orchestration: MCP server spawns lightweight indexer containers on-demand via Docker socket
  • Multi-Repository Support: Each repository gets its own merkle tree state, but shares the vector & graph databases
  • Shared Backend: All projects use the same Qdrant & Neo4j instances, enabling cross-repository search and relationship tracking
  • Job-Based Processing: Background jobs with progress tracking for large codebases
  • Content-Addressable Caching: Embeddings are cached by content hash, shared across all repositories
  • Relationship Extraction: AST-based extraction of CALLS, IMPORTS, EXTENDS, and IMPLEMENTS relationships
  • External Dependency Tracking: Automatic creation of placeholder nodes for unresolved function calls

Quick Start

See QUICK_START.md for detailed setup instructions.

Prerequisites

  1. Docker Desktop (or Docker + Docker Compose)
  2. Ollama running locally with an embedding model:
    # Install Ollama: https://ollama.ai
    
    # Recommended: Google's Gemma embedding model (best quality)
    ollama pull embeddinggemma:latest
    
    # Alternative: Nomic Embed (faster, smaller)
    ollama pull nomic-embed-text

Two Deployment Options

Option A: Centralized Server (Recommended)

Best for: Indexing from the MCP server, querying across all repositories

# 1. Start the backend
cd codebase-contextifier-9000
docker-compose up -d

# 2. Configure Claude Desktop (see below)

# 3. Index any repository
# In Claude: "Index the repository at /Users/me/projects/my-app"

Option B: Per-Project Setup

Best for: Each project manages its own indexing

# 1. Start shared backend (once)
cd codebase-contextifier-9000
docker-compose up -d

# 2. Copy .mcp.json to each project
cp .mcp.json.template ~/projects/my-app/.mcp.json

# 3. Open project in Claude Code
cd ~/projects/my-app
claude-code .

See MULTI_PROJECT_SETUP.md for details.

Claude Desktop Configuration

For Centralized Server (Option A):

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "codebase-contextifier": {
      "command": "docker",
      "args": [
        "exec",
        "-i",
        "codebase-mcp-server",
        "python",
        "-m",
        "src.server"
      ]
    }
  }
}

For Per-Project Setup (Option B):

Just copy .mcp.json.template to your project directory - no manual configuration needed!

Usage

Once configured, you can use these tools in Claude Desktop or Claude Code:

Index any repository on your system:

Claude, index the repository at /Users/me/projects/my-app

The system spawns a container, indexes the repository in the background, and reports progress.

Monitor indexing progress:

Claude, show me the status of job abc123

Search for code across all indexed repositories:

Claude, search for "authentication logic" in the codebase

Search with filters:

Claude, search for "error handling" filtering by language=python and repo_name=my-api

Extract symbols from a file:

Claude, get all functions from /workspace/src/utils.py

Find all usages of a function (graph query):

Claude, find all places where authenticate_user is called

Find dependencies of a function (graph query):

Claude, show me all functions that processPayment depends on

Detect and index external dependencies:

Claude, detect available WordPress plugins in this project
Claude, index the woocommerce plugin into the knowledge base

Check system status:

Claude, show me the indexing status and list all jobs

MCP Tools

Indexing Tools

index_repository

Index a repository from any directory on your host machine by spawning a lightweight indexer container.

Parameters:

  • host_path (string, required): Absolute path on host machine to repository (e.g., /Users/me/projects/my-app)
  • repo_name (string, optional): Unique identifier for this repository (defaults to directory name)
  • incremental (bool): Use incremental indexing to only re-index changed files (default: true)
  • exclude_patterns (string, optional): Comma-separated glob patterns to exclude (e.g., "node_modules/*,dist/*")

Returns:

{
  "success": true,
  "job_id": "abc123def456",
  "repo_name": "my-app",
  "status": "queued",
  "message": "Background indexing started for 'my-app'"
}

Example:

# Index a WordPress site, excluding plugins and uploads
await index_repository(
    host_path="/Users/me/sites/my-wordpress",
    repo_name="my-wordpress",
    exclude_patterns="wp-content/plugins/*,wp-content/uploads/*,wp-includes/*"
)

get_job_status

Get the status and progress of an indexing job.

Parameters:

  • job_id (string, required): Job identifier returned from index_repository

Returns:

{
  "success": true,
  "job_id": "abc123def456",
  "repo_name": "my-app",
  "repo_path": "/Users/me/projects/my-app",
  "status": "running",
  "created_at": 1698765432.123,
  "started_at": 1698765433.456,
  "elapsed_seconds": 45.2,
  "progress": {
    "current_file": 45,
    "total_files": 100,
    "progress_pct": 45.0,
    "current_file_path": "/workspace/src/api/auth.py",
    "chunks_indexed": 234,
    "failed_files_count": 2,
    "cache_hit_rate": "35.50%"
  }
}

Status values: "queued", "running", "completed", "failed", "cancelled"

list_indexing_jobs

List all indexing jobs (past and present).

Returns:

{
  "success": true,
  "total_jobs": 3,
  "jobs": [
    {
      "job_id": "abc123",
      "repo_name": "my-api",
      "status": "completed",
      "progress": { "progress_pct": 100.0, ... }
    },
    {
      "job_id": "def456",
      "repo_name": "frontend",
      "status": "running",
      "progress": { "progress_pct": 67.5, ... }
    }
  ]
}

cancel_indexing_job

Cancel a running indexing job.

Parameters:

  • job_id (string, required): Job identifier to cancel

Returns:

{
  "success": true,
  "message": "Job abc123 cancelled successfully"
}

Search Tools

search_code

Search code using natural language queries with semantic understanding across all indexed repositories.

Parameters:

  • query (string, required): Natural language search query (e.g., "authentication logic", "error handling")
  • limit (int): Maximum number of results to return (default: 10)
  • repo_name (string, optional): Filter by repository name (searches all repos if not specified)
  • language (string, optional): Filter by programming language (e.g., "python", "typescript", "php")
  • file_path_filter (string, optional): Filter by file path pattern (e.g., "src/components")
  • chunk_type (string, optional): Filter by chunk type (e.g., "function", "class", "method")

Returns:

{
  "success": true,
  "query": "authentication logic",
  "total_results": 5,
  "results": [
    {
      "rank": 1,
      "score": 0.8234,
      "repo_name": "backend-api",
      "file": "/workspace/src/auth/login.ts",
      "lines": "42-68",
      "language": "typescript",
      "type": "function",
      "context": "class:AuthService",
      "code": "async function authenticateUser(username, password) { ... }"
    }
  ]
}

get_symbols

Extract symbols from a file using AST parsing.

Parameters:

  • file_path (string): Path to source file
  • symbol_type (string, optional): Filter by type (e.g., "function", "class")

Returns:

{
  "success": true,
  "file_path": "/workspace/src/utils.py",
  "total_symbols": 15,
  "symbols": [
    {
      "name": "format_date",
      "type": "function_definition",
      "start_line": 42,
      "end_line": 58,
      "context": "N/A",
      "language": "python"
    }
  ]
}

Graph Query Tools

find_usages

Find all places where a function, class, or symbol is used across the codebase using the graph database.

Parameters:

  • symbol_name (string, required): Name of the function/class to find usages for
  • repo_name (string, optional): Filter by repository name

Returns:

{
  "success": true,
  "symbol_name": "authenticate_user",
  "total_usages": 12,
  "usages": [
    {
      "caller": "LoginController.handleLogin",
      "caller_file": "/workspace/src/controllers/login.ts",
      "line_number": 42,
      "relationship_type": "CALLS"
    }
  ]
}

find_dependencies

Find all functions, classes, or imports that a symbol depends on using the graph database.

Parameters:

  • symbol_name (string, required): Name of the function/class to analyze
  • repo_name (string, optional): Filter by repository name

Returns:

{
  "success": true,
  "symbol_name": "processPayment",
  "total_dependencies": 8,
  "dependencies": [
    {
      "target": "validateCard",
      "target_file": "/workspace/src/utils/validation.ts",
      "relationship_type": "CALLS",
      "is_external": false
    },
    {
      "target": "stripe.charges.create",
      "relationship_type": "CALLS",
      "is_external": true
    }
  ]
}

query_graph

Execute custom Cypher queries against the Neo4j graph database for advanced relationship analysis.

Parameters:

  • cypher_query (string, required): Cypher query to execute
  • limit (int, optional): Maximum number of results (default: 100)

Returns:

{
  "success": true,
  "query": "MATCH (f:Function)-[:CALLS]->(ext:ExternalFunction) WHERE ext.name =~ 'wp_.*' RETURN f.name, ext.name",
  "results": [
    {"f.name": "enqueue_scripts", "ext.name": "wp_enqueue_script"},
    {"f.name": "setup_theme", "ext.name": "wp_register_nav_menu"}
  ],
  "total_results": 2
}

Dependency Tools

detect_dependencies

Detect available dependencies in the workspace (WordPress plugins/themes, Composer packages, npm modules).

Parameters:

  • workspace_path (string, optional): Path to workspace (defaults to current workspace)

Returns:

{
  "success": true,
  "dependencies": {
    "wordpress_plugins": ["woocommerce", "advanced-custom-fields"],
    "wordpress_themes": ["twentytwentyfour"],
    "composer_packages": ["symfony/console", "guzzlehttp/guzzle"],
    "npm_packages": ["react", "typescript"]
  },
  "total_dependencies": 6
}

index_dependencies

Index specific dependencies into the knowledge base for better understanding of external APIs.

Parameters:

  • dependency_names (array, required): List of dependency names to index (e.g., ["woocommerce", "react"])
  • workspace_id (string, required): Unique identifier for the workspace/project
  • workspace_path (string, optional): Path to workspace

Returns:

{
  "success": true,
  "indexed_dependencies": ["woocommerce"],
  "total_chunks": 1247,
  "message": "Successfully indexed 1 dependencies with 1247 chunks"
}

list_indexed_dependencies

List all dependencies that have been indexed in the knowledge base.

Returns:

{
  "success": true,
  "dependencies": [
    {
      "name": "woocommerce",
      "version": "8.5.0",
      "type": "wordpress_plugin",
      "workspaces": ["my-store", "test-site"],
      "chunks_count": 1247,
      "indexed_at": "2024-01-15T10:30:00Z"
    }
  ],
  "total_dependencies": 1
}

Status Tools

get_indexing_status

Get statistics about the index, including vector DB, graph DB, and cache metrics.

Returns:

{
  "success": true,
  "code_db": {
    "total_chunks": 2450,
    "vectors_count": 2450,
    "status": "green"
  },
  "knowledge_db": {
    "total_chunks": 1247,
    "indexed_dependencies": ["woocommerce"]
  },
  "graph_db": {
    "enabled": true,
    "total_nodes": 2230,
    "total_relationships": 4407,
    "node_types": {
      "Function": 1459,
      "ExternalFunction": 771
    }
  },
  "index": {
    "indexed_files": 150,
    "total_chunks": 2450
  },
  "cache": {
    "enabled": true,
    "cached_embeddings": 2450,
    "total_size_mb": 18.5
  }
}

clear_index

Clear the entire index (useful for fresh start).

get_watcher_status

Get status of the real-time file watcher.

Returns:

{
  "success": true,
  "enabled": true,
  "running": true,
  "watch_path": "/workspace",
  "debounce_seconds": 2.0
}

health_check

Check health status of all components (Ollama, Qdrant, Neo4j).

Supported Languages

Language Extensions Support Level
Python .py, .pyw Full
TypeScript .ts, .tsx Full
JavaScript .js, .jsx, .mjs, .cjs Full
PHP .php, .phtml Full
Go .go Full
Rust .rs Full
Java .java Full
C++ .cpp, .cc, .hpp, .hh Full
C .c, .h Full
C# .cs Full

Configuration

Environment Variables

Variable Default Description
CODEBASE_PATH ./sample_codebase Path to codebase to index
OLLAMA_HOST http://host.docker.internal:11434 Ollama API endpoint
EMBEDDING_MODEL embeddinggemma:latest Ollama embedding model to use
QDRANT_HOST qdrant Qdrant server hostname
QDRANT_PORT 6333 Qdrant server port
ENABLE_GRAPH_DB false Enable Neo4j graph database
NEO4J_URI bolt://neo4j:7687 Neo4j connection URI
NEO4J_USER neo4j Neo4j username
NEO4J_PASSWORD password Neo4j password
INDEX_PATH /index Path for index metadata
CACHE_PATH /cache Path for embedding cache
WORKSPACE_PATH /workspace Path to mounted codebase
MAX_CHUNK_SIZE 2048 Maximum chunk size in characters
BATCH_SIZE 32 Embedding batch size
MAX_CONCURRENT_EMBEDDINGS 4 Concurrent embedding requests
ENABLE_FILE_WATCHER true Enable real-time file watching
WATCHER_DEBOUNCE_SECONDS 2.0 Delay before processing file changes
LOG_LEVEL INFO Logging level

Recommended Embedding Models

  • embeddinggemma:latest (recommended - best quality)
  • nomic-embed-text (good balance of speed and quality)
  • mxbai-embed-large (higher accuracy, slower)
  • all-minilm (fastest, lower accuracy)

Performance

Indexing Performance

  • Medium codebase (5K-50K files): 2-10 minutes initial indexing
  • Incremental updates: 10-60 seconds for typical changes
  • Cache hit rate: 80-95% on subsequent runs
  • Embedding generation: ~100-500 chunks/minute (depends on Ollama performance)

Search Performance

  • Latency: Sub-second semantic search
  • Throughput: 10-50 queries/second
  • Accuracy: 30% better than fixed-size chunking (from research)

Troubleshooting

"Ollama health check failed"

  1. Make sure Ollama is running: ollama serve
  2. Pull the embedding model: ollama pull embeddinggemma:latest
  3. Check Docker can access host: Test with curl http://host.docker.internal:11434

"Qdrant connection failed"

  1. Check Qdrant container is running: docker-compose ps
  2. Check Qdrant logs: docker-compose logs qdrant
  3. Restart services: docker-compose restart

"Graph database not enabled"

  1. Set ENABLE_GRAPH_DB=true in your .env file or .mcp.json
  2. Ensure Neo4j environment variables are configured: NEO4J_URI, NEO4J_USER, NEO4J_PASSWORD
  3. Check Neo4j container is running: docker-compose ps
  4. Check Neo4j logs: docker-compose logs neo4j
  5. Test Neo4j connection: docker exec codebase-neo4j cypher-shell -u neo4j -p codebase123 "RETURN 1"

"No supported files found"

  1. Check CODEBASE_PATH is correct in .env
  2. Verify files have supported extensions
  3. Check .gitignore isn't excluding too much

Slow indexing

  1. Reduce BATCH_SIZE if running low on RAM
  2. Increase MAX_CONCURRENT_EMBEDDINGS if you have spare CPU
  3. Use incremental=true for re-indexing

Development

Running Locally (Without Docker)

# Install dependencies
pip install -r requirements.txt

# Set environment variables
export QDRANT_HOST=localhost
export OLLAMA_HOST=http://localhost:11434
export INDEX_PATH=./index
export CACHE_PATH=./cache
export WORKSPACE_PATH=/path/to/your/codebase

# Start Qdrant
docker run -p 6333:6333 qdrant/qdrant

# Run server
python -m src.server

Running Tests

pip install -e ".[dev]"
pytest

Code Quality

# Format code
black src/

# Lint code
ruff src/

Architecture Details

AST-Aware Chunking

The system uses tree-sitter to parse code into Abstract Syntax Trees (ASTs), then extracts semantic chunks that respect:

  • Function boundaries
  • Class definitions
  • Method boundaries
  • Interface/trait definitions

This achieves 30% better accuracy than fixed-size chunking according to research (arXiv:2506.15655).

Incremental Indexing

Uses Merkle tree-based change detection:

  1. Compute Blake3 hash of each file
  2. Compare with previous state
  3. Only re-index changed files
  4. Update vector database incrementally

Typical cache hit rates: 80-95%

Content-Addressable Storage

Embeddings are cached using content hashing:

cache_key = blake3(model_name + file_content)

This enables:

  • Team sharing of cached embeddings
  • Fast re-indexing after git operations
  • Deterministic caching across machines

Roadmap

  • Real-time file system watcher for instant updates
  • Multi-repo search with shared backend
  • Job-based background indexing with progress tracking
  • On-demand container spawning for flexible repository indexing
  • Neo4j integration for relationship tracking - Track function calls, imports, inheritance, with external dependency placeholders
  • Dependency knowledge base - Index WordPress plugins, Composer packages, npm modules
  • Reranking with cross-encoders for improved accuracy
  • Fine-tuned embeddings for domain-specific code
  • HTTP transport for remote MCP servers
  • Web UI for search and visualization
  • Graph-based code navigation UI (Neo4j Browser or custom visualization)

Research & References

Based on cutting-edge research in semantic code search:

  • cAST (arXiv:2506.15655): AST-aware chunking methodology
  • CodeRAG (arXiv:2504.10046): Graph-augmented retrieval
  • Model Context Protocol: Anthropic's standard for AI tool integration
  • Qdrant: High-performance vector database
  • tree-sitter: Incremental parsing library

License

MIT

Contributing

Contributions welcome! Please open an issue or PR.

Support

For issues, questions, or feature requests, please open a GitHub issue.

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MCP server for semantic code search with AST-aware chunking, incremental indexing, and real-time monitoring. --- idk if it works or, moreover, is actually helpful. But it is cool.

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