AI-Assisted Code Transformations via Model Context Protocol

CEDARScript MCP Server exposes the powerful CEDARScript Editor through the Model Context Protocol (MCP), enabling AI agents like Claude to perform intelligent, semantic-aware code transformations.

• 🔒 Secure by Default: Path validation, sandboxing, read-only mode
• 🎯 Dry-Run Mode: Preview changes before applying
• 🌲 Tree-Sitter Powered: Language-aware code analysis
• 📡 STDIO Transport: Simple subprocess integration (no HTTP overhead)
• 🛠️ Production-Ready: Comprehensive logging, error handling, testing

pip install cedarscript-mcp-server

1. Open Claude Desktop configuration (usually ~/.config/Claude/claude_desktop_config.json)

2. Add CEDARScript MCP server:

{
  "mcpServers": {
    "cedarscript": {
      "command": "python",
      "args": [
        "-m",
        "cedarscript_mcp.server",
        "--root",
        "/path/to/your/project"
      ]
    }
  }
}

3. Restart Claude Desktop

4. Ask Claude to use CEDARScript:

   • "Parse this CEDARScript command: UPDATE myfile.py SET imports.append('import os')"
   • "Apply this transformation (preview first): UPDATE calculator.py SET function:calculate REPLACE 'x + 1' WITH 'x + 2'"

# Start server (STDIO mode)
python -m cedarscript_mcp.server --root /path/to/project

# With custom options
python -m cedarscript_mcp.server \
  --root /path/to/project \
  --read-only \
  --log-level DEBUG \
  --max-file-size 10485760

CEDARScript MCP Server is a thin adapter layer that:

1. Accepts JSON-RPC requests over STDIO
2. Validates paths and security constraints
3. Delegates to CEDARScript Editor for execution
4. Returns structured results or error messages

┌─────────────────────────────────┐
│   Claude Desktop / VS Code      │
│        (MCP Client)             │
└────────────┬────────────────────┘
             │ JSON-RPC over STDIO
┌────────────▼────────────────────┐
│  CEDARScript MCP Server         │
│  • Security (path validation)   │
│  • Tools (parse, apply, list)   │
│  • Adapters (protocol mapping)  │
└────────────┬────────────────────┘
             │
┌────────────▼────────────────────┐
│   CEDARScript Editor (core)     │
│  • AST parsing                  │
│  • Tree-sitter analysis         │
│  • File transformations         │
└─────────────────────────────────┘

Parse and validate CEDARScript commands without execution.

Parameters:

• content (string): CEDARScript commands

Returns: Parsed AST commands

Example:

{
  "content": "UPDATE myfile.py SET imports.append('import os')"
}

Apply CEDARScript transformations to code files.

Parameters:

• commands (string): CEDARScript commands
• root (string): Project root directory path
• dry_run (boolean, default: true): Preview changes without writing

Returns: Results, diffs (if dry_run), affected files

Example:

{
  "commands": "UPDATE calculator.py SET function:add REPLACE 'x + y' WITH 'x + y + 1'",
  "root": "/path/to/project",
  "dry_run": true
}

List server capabilities and supported features.

Returns: Server version, features, security settings

• CEDARSCRIPT_ROOT: Default project root (default: current directory)
• CEDARSCRIPT_LOG_LEVEL: Logging level (DEBUG, INFO, WARNING, ERROR)
• CEDARSCRIPT_LOG_FORMAT: Log format (text, json)
• CEDARSCRIPT_READ_ONLY: Force read-only mode (true/false)
• CEDARSCRIPT_MAX_FILE_SIZE: Max file size in bytes (default: 10485760)

python -m cedarscript_mcp.server \
  --root /path/to/project \         # Project root directory
  --read-only \                     # Enable read-only mode
  --log-level DEBUG \               # Logging level
  --max-file-size 10485760          # Max file size (bytes)

• All file paths are validated against the specified root directory
• Path traversal attacks (../../../etc/passwd) are blocked
• Symlinks are resolved and validated

Files matching these patterns are automatically rejected:

• .git/**, node_modules/**, __pycache__/**
• .env, *.env, .env.*
• credentials.json, *.key, *.pem

When enabled, all write operations are rejected (parsing/analysis only).

Configurable maximum file size (default: 10MB) to prevent resource exhaustion.

# Clone repository
git clone https://github.com/CEDARScript/cedarscript-mcp-server.git
cd cedarscript-mcp-server

# Install development dependencies
make install

# Run tests
make test

# Run with coverage
make test-cov

# Format and lint
make check

make help              # Show all available targets
make install           # Install with dev dependencies
make test              # Run full test suite
make test-fast         # Run tests (skip integration)
make check             # Format, lint, security checks
make run               # Launch server (demo mode)
make build             # Build distribution packages

See planning/MAKEFILE_DESIGN.md for complete target documentation.

# Run all tests
make test

# With coverage report
make test-cov

# Watch mode (auto-rerun on changes)
make test-watch

# Test against multiple cedarscript-editor versions
make test-matrix

• ARCHITECTURE.md: System design, protocol mapping, security model
• IMPLEMENTATION.md: Step-by-step implementation guide
• MAKEFILE_DESIGN.md: Makefile targets and automation
• Examples: Claude Desktop, VS Code, quickstart guides

See examples/claude_desktop.json for drop-in configuration.

See examples/vscode_mcp.json for VS Code setup.

from cedarscript_mcp import PathValidator, apply_cedarscript_tool

# Create validator
validator = PathValidator(Path("/path/to/project"))

# Apply transformation (dry-run)
result = apply_cedarscript_tool(
    commands="UPDATE myfile.py SET imports.append('import os')",
    root="/path/to/project",
    dry_run=True,
    validator=validator
)

print(result)

Issue: ModuleNotFoundError: No module named 'mcp'

Solution: Install MCP SDK: pip install mcp>=1.0.0

Issue: SecurityError: Path escape attempt

Solution: Ensure file paths are within the specified root directory.

Issue: SecurityError: Write operation rejected

Solution: Remove --read-only flag or set CEDARSCRIPT_READ_ONLY=false.

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Run make check test before committing
4. Submit a pull request

Apache License 2.0 - see LICENSE for details.

• CEDARScript Editor - Core transformation library
• CEDARScript AST Parser - Language parser
• Model Context Protocol - MCP specification

• Issues: GitHub Issues
• Documentation: GitHub README
• Email: [email protected]

Made with ❤️ by the CEDARScript Team