SACL MCP Server

Semantic-Augmented Reranking and Localization for Code Retrieval

A Model Context Protocol (MCP) server that implements the SACL research framework to provide bias-aware code retrieval for AI coding assistants like Claude Code, Cursor, and other MCP-enabled tools.

🎯 Overview

SACL addresses the critical problem of textual bias in code retrieval systems. Traditional systems over-rely on surface-level features like docstrings, comments, and variable names, leading to biased results that favor well-documented code regardless of functional relevance.

Key Features

• 🧠 Bias Detection: Identifies over-reliance on textual features
• 🔍 Semantic Augmentation: Enriches code understanding beyond surface text
• 📊 Intelligent Reranking: Prioritizes functional relevance over documentation
• 🎯 Code Localization: Pinpoints functionally relevant code segments
• 🔗 Relationship Analysis: Maps code dependencies and relationships
• 🎨 Context-Aware Retrieval: Returns results with related components
• 🚀 Agent-Controlled Updates: Explicit file updates for Docker compatibility
• 🗄️ Knowledge Graph: Persistent semantic storage with Graphiti/Neo4j
• 🔧 MCP Integration: Works with Claude Code, Cursor, and other AI tools

🏗️ Architecture

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   AI Assistant  │────│  SACL MCP Server │────│   Graphiti/Neo4j │
│ (Claude, Cursor)│    │                 │    │  Knowledge Graph │
└─────────────────┘    └─────────────────┘    └─────────────────┘
                              │
                    ┌─────────────────┐
                    │  SACL Framework │
                    │                 │
                    │ • Bias Detection│
                    │ • Semantic Aug. │
                    │ • Reranking     │
                    │ • Localization  │
                    │ • Relationships │
                    │ • Context-Aware │
                    └─────────────────┘

📊 SACL Framework

Stage 1: Bias Detection

Identifies three types of textual bias:

• Docstring Dependency: Over-reliance on documentation
• Identifier Name Bias: Focusing on variable/function names
• Comment Over-reliance: Prioritizing commented code

Stage 2: Semantic Augmentation

Enriches code representations with:

• Functional Signatures: What the code actually does
• Behavior Patterns: Computational patterns (iteration, recursion, etc.)
• Structural Features: Complexity metrics, AST analysis
• Augmented Embeddings: Bias-adjusted semantic vectors

Stage 3: Reranking & Localization

• Bias-Aware Ranking: Reduces textual weight based on bias score
• Code Localization: Identifies functionally relevant segments
• Semantic Similarity: Uses augmented embeddings
• Functional Relevance: Considers computational patterns

Stage 4: Relationship Analysis 🆕

Maps code relationships and dependencies:

• Import/Export Analysis: Module dependencies and exports
• Function Call Mapping: Call graphs and method invocations
• Class Inheritance: Extends/implements relationships
• Dependency Tracking: External and internal dependencies
• Context-Aware Results: Related components with each query result

🧪 Example Workflow

1. Repository Analysis:

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   AI Assistant → analyze_repository → SACL processes all files → Knowledge graph populated

2. Code Query with Context:

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   AI Assistant → query_code_with_context("authentication") → SACL retrieval → Context-aware results

3. File Updates:

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   AI modifies code → update_file("src/auth.js", "modified") → SACL re-analyzes → Relationships updated

4. Relationship Exploration:

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   AI Assistant → get_relationships("UserController.js") → Dependency graph → Related components

5. Results Include:

   • Original textual similarity score
   • Semantic similarity score
   • Bias-adjusted final score
   • Localized code regions
   • Related components and dependencies
   • Context explanation with relationship importance
   • Explanation of ranking decisions

📈 Performance

Based on SACL research benchmarks:

• 12.8% improvement in Recall@1 on HumanEval
• 9.4% improvement on MBPP
• 7.0% improvement on SWE-Bench-Lite
• P95 latency: <300ms for retrieval operations

🔍 Bias Analysis Example

🧠 SACL Bias Analysis

File: src/algorithms/quicksort.js

Bias Metrics:
• Overall Bias Score: 73.2% 🔴
• Semantic Pattern: Recursive divide-and-conquer sorting
• Functional Signature: Array input → sorted array output

Bias Indicators:
• docstring_dependency: High docstring dependency (15.3% of code)
• identifier_name_bias: High reliance on descriptive names
• comment_over_reliance: Excessive comments (18.7% of code)

💡 Improvement Suggestions:
• Reduce reliance on variable naming for semantic understanding
• Focus on structural patterns over comments
• Improve functional signature extraction

🛠️ Development

Project Structure

src/
├── core/                    # SACL framework implementation
│   ├── BiasDetector.ts      # Textual bias detection
│   ├── SemanticAugmenter.ts # Semantic enhancement
│   ├── SACLReranker.ts      # Reranking and localization with context
│   └── SACLProcessor.ts     # Main orchestrator with relationship support
├── mcp/                     # MCP server implementation
│   └── SACLMCPServer.ts     # MCP protocol handlers (9 tools)
├── graphiti/                # Knowledge graph integration
│   └── GraphitiClient.ts    # Graphiti/Neo4j interface with relationships
├── utils/                   # Utility modules
│   └── CodeAnalyzer.ts      # AST analysis and relationship extraction
├── types/                   # TypeScript type definitions
│   ├── index.ts             # Core types and interfaces
│   └── relationships.ts     # Relationship type definitions
└── index.ts                 # Application entry point

Building

npm run build    # Build TypeScript
npm run dev      # Development with auto-reload
npm run lint     # Code linting
npm run format   # Code formatting
npm test         # Run tests

Contributing

1. Fork the repository
2. Create a feature branch
3. Implement changes following SACL methodology
4. Add tests for new functionality
5. Submit a pull request

📚 Research Background

This implementation is based on the research paper:

"SACL: Understanding and Combating Textual Bias in Code Retrieval with Semantic-Augmented Reranking and Localization"

• Authors: Dhruv Gupta, Gayathri Ganesh Lakshmy, Yiqing Xie
• arXiv: 2506.20081v2

Key Research Contributions

1. Systematic Bias Detection: Identifies textual bias through feature masking
2. Semantic Augmentation: Enhances code understanding beyond text
3. Bias-Aware Ranking: Reduces surface-level feature dependency
4. Localization: Pinpoints functionally relevant code regions

🔗 Integration

Supported AI Tools

• Claude Code: Direct MCP integration
• Cursor: MCP server connection
• VS Code Extensions: Via MCP protocol
• Custom Tools: Any MCP-compatible client

Language Support

• JavaScript/TypeScript: Full AST analysis with relationship extraction

  • Import/export tracking
  • Function call analysis
  • Class inheritance detection
  • Dynamic imports support

• Python: Regex-based analysis

  • Import statement parsing
  • Class inheritance detection
  • Function call patterns

• Other Languages (Java, C++, C#, Go, Rust): Basic analysis

  • Import/include statements
  • Class declarations
  • Function definitions

• Extensible: Easy to add new language analyzers

📄 License

MIT License - see LICENSE file for details.

🆘 Support

• Issues: GitHub Issues
• Documentation: See /docs directory
• Research Paper: arXiv:2506.20081v2

🔮 Future Enhancements

• Multi-language AST parsing for all supported languages
• Real-time Graphiti integration (currently uses mock methods)
• Semantic relationship detection beyond syntactic analysis
• Visual relationship graphs in MCP responses
• Custom bias threshold configuration per project
• Integration with Language Server Protocol (LSP)
• Advanced localization algorithms with machine learning
• Performance optimizations for large codebases (>10k files)
• Real-time bias notifications during code writing
• Custom relationship type definitions

SACL MCP Server - Bringing research-backed bias-aware code retrieval to AI coding assistants.

🚀 Quick Start

Prerequisites

• Node.js 18+
• Neo4j database
• OpenAI API key

Installation

# Clone the repository
git clone <repository-url>
cd sacl

# Install dependencies
npm install

# Copy environment configuration
cp .env.example .env

# Edit .env with your settings
OPENAI_API_KEY=your_key_here
NEO4J_URI=bolt://localhost:7687
NEO4J_USER=neo4j
NEO4J_PASSWORD=your_password

Using Docker (Recommended)

# Start Neo4j and SACL server
docker-compose up -d

# Check logs
docker-compose logs -f sacl-mcp-server

Manual Setup

# Build the project
npm run build

# Start the server
npm start

🔧 Configuration

Environment Variables

🎮 Usage

MCP Tools

The SACL server provides comprehensive MCP tools for bias-aware code analysis:

1. analyze_repository

Performs full SACL analysis of a repository:

{
  "repositoryPath": "/path/to/repo",
  "incremental": false
}

2. query_code

Bias-aware code search with optional context:

{
  "query": "function that sorts arrays efficiently",
  "repositoryPath": "/path/to/repo",
  "maxResults": 10,
  "includeContext": false  // Set true for relationship context
}

3. query_code_with_context 🆕

Enhanced search with relationship context and related components:

{
  "query": "authentication middleware",
  "repositoryPath": "/path/to/repo",
  "maxResults": 10,
  "includeRelated": true
}

4. update_file 🆕

Explicitly update single file analysis when changes are made:

{
  "filePath": "src/services/auth.js",
  "changeType": "modified"  // "created", "modified", or "deleted"
}

5. update_files 🆕

Batch update multiple files:

{
  "files": [
    { "filePath": "src/index.js", "changeType": "modified" },
    { "filePath": "src/utils/new.js", "changeType": "created" }
  ]
}

6. get_relationships 🆕

Analyze code relationships and dependencies:

{
  "filePath": "src/controllers/UserController.js",
  "maxDepth": 3,
  "relationshipTypes": ["imports", "calls", "extends"]  // Optional filter
}

7. get_file_context 🆕

Get comprehensive context for a file:

{
  "filePath": "src/models/User.js",
  "includeSnippets": true  // Include code previews
}

8. get_bias_analysis

Detailed bias metrics and debugging:

{
  "filePath": "src/utils/sort.js"  // Optional
}

9. get_system_stats

System performance and statistics:

{}

MCP Client Configuration

Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "sacl": {
      "command": "node",
      "args": ["/path/to/sacl/dist/index.js"],
      "env": {
        "OPENAI_API_KEY": "your-key",
        "NEO4J_URI": "bolt://localhost:7687",
        "NEO4J_USER": "neo4j",
        "NEO4J_PASSWORD": "password"
      }
    }
  }
}

Cursor IDE

Configure in your Cursor settings to connect to the SACL MCP server.