Splice Weaver MCP

Splice Weaver MCP

An MCP (Model Context Protocol) server that provides ast-grep functionality to language models with automatic binary bundling and dual support for both direct CLI access and guided workflows.

Features

Core Tools

• find_scope: Universal scope navigation using relational rules
• execute_rule: Rule-based operations (search, replace, scan)

Binary Bundling

• Automatic Download: ast-grep binary (v0.38.7) is automatically downloaded if not found
• Multi-Platform Support: Supports Linux (x86_64, aarch64), macOS (Intel, Apple Silicon), Windows
• System Binary Detection: Uses system-installed ast-grep if available, otherwise downloads bundled version

MCP Resources

• ast-grep://binary-path: Get the path to the ast-grep executable
• ast-grep://cli-reference: Complete CLI documentation with bundled binary path
• ast-grep://rule-examples: YAML rule configuration examples
• ast-grep://relational-patterns: Examples of relational rules for scope navigation
• ast-grep://node-kinds: Tree-sitter node types by language

MCP Prompts

• scope_navigation_rule: Generate YAML rules to find specific scope types
• transform_in_scope: Generate YAML rules to transform code within scopes

Prerequisites

• Rust toolchain
• No ast-grep installation required - the server bundles the binary automatically

Installation

# From GitHub
cargo install --git https://github.com/micahscopes/splice-weaver-mcp

Usage

As MCP Server

Add to your MCP client configuration:

{
  "mcp": {
    "servers": {
      "ast-grep": {
        "command": "splice-weaver-mcp",
        "args": []
      }
    }
  }
}

Direct Usage

# If installed via cargo install
splice-weaver-mcp

# If built manually
./target/release/splice-weaver-mcp

Binary Management

The server automatically manages the ast-grep binary:

1. System Check: First checks if ast-grep is installed on the system
2. Auto-Download: If not found, downloads the appropriate binary for your platform
3. Bundled Storage: Stores the binary in ./bundled_binaries/ relative to the executable

Supported platforms:

• Linux x86_64 (x86_64-unknown-linux-gnu)
• Linux ARM64 (aarch64-unknown-linux-gnu)
• macOS Intel (x86_64-apple-darwin)
• macOS Apple Silicon (aarch64-apple-darwin)
• Windows x64 (x86_64-pc-windows-msvc)
• Windows x86 (i686-pc-windows-msvc)

Design Philosophy

This server implements a dual approach to ast-grep access:

1. Direct Access: Full CLI power for experienced users and large LLMs
2. Guided Workflows: Structured templates and examples for small LLMs

For complete ast-grep documentation, visit: https://ast-grep.github.io/

Documentation

Comprehensive project documentation is available in the notes-log/ directory:

• Project Evolution Summary - Complete overview and goals
• Design Decisions - Architecture and research-driven design
• Interface Summary - Technical implementation details
• Testing Guide - Comprehensive testing approach
• Full Documentation Index - Complete navigation guide

License

MIT