Tree-Hugger-JS MCP Server

An MCP (Model Context Protocol) server that provides AI agents with powerful JavaScript/TypeScript code analysis and transformation capabilities using the tree-hugger-js library.

Features

🔍 Code Analysis

• Parse JavaScript, TypeScript, JSX, and TSX files or code strings

• Find patterns using intuitive syntax (e.g., function, class[name="MyClass"])

• Extract functions, classes, imports with detailed metadata

• Navigate AST nodes and analyze code structure

• Get nodes at specific positions

🔧 Code Transformation

• Rename identifiers throughout code

• Remove unused imports

• Chain multiple transformations

• Insert code before/after patterns

• Preview transformations before applying

📊 Code Intelligence

• Scope analysis and variable binding

• Pattern matching with CSS-like selectors

• Support for async functions, classes, methods

• TypeScript type import handling

Installation & Usage

🚀 Quick Start (Recommended)

Try immediately with npx - no installation required:

📦 Global Installation

🔧 Development Setup

MCP Client Configuration

Using with Claude Code

Add to your MCP client configuration:

Alternative Configurations

Tools

Code Analysis Tools

parse_code

Parse JavaScript/TypeScript code from file or string.

Parameters:

• source (string): File path or code string to parse

• isFilePath (boolean, optional): Whether source is a file path (auto-detected if not provided)

• language (string, optional): Language to use (javascript, typescript, jsx, tsx)

Example:

find_pattern

Find first node matching a pattern.

Parameters:

• pattern (string): Pattern to match using tree-hugger-js syntax

Examples:

find_all_pattern

Find all nodes matching a pattern.

Parameters:

• pattern (string): Pattern to match

• limit (number, optional): Maximum matches to return

get_functions

Get all functions with details.

Parameters:

• includeAnonymous (boolean, optional): Include anonymous functions (default: true)

• asyncOnly (boolean, optional): Only return async functions (default: false)

get_classes

Get all classes with methods and properties.

Parameters:

• includeProperties (boolean, optional): Include class properties (default: true)

• includeMethods (boolean, optional): Include class methods (default: true)

get_imports

Get all import statements.

Parameters:

• includeTypeImports (boolean, optional): Include TypeScript type-only imports (default: true)

Code Transformation Tools

rename_identifier

Rename all occurrences of an identifier.

Parameters:

• oldName (string): Current identifier name

• newName (string): New identifier name

• preview (boolean, optional): Return preview only (default: false)

Example:

remove_unused_imports

Remove unused import statements.

Parameters:

• preview (boolean, optional): Return preview only (default: false)

transform_code

Apply multiple transformations in sequence.

Parameters:

• operations (array): Array of transformation operations

• preview (boolean, optional): Return preview only (default: false)

Example:

insert_code

Insert code before or after nodes matching a pattern.

Parameters:

• pattern (string): Pattern to match for insertion points

• code (string): Code to insert

• position (string): "before" or "after"

• preview (boolean, optional): Return preview only (default: false)

Navigation Tools

get_node_at_position

Get AST node at specific line and column.

Parameters:

• line (number): Line number (1-based)

• column (number): Column number (0-based)

analyze_scopes

Analyze variable scopes and bindings.

Parameters:

• includeBuiltins (boolean, optional): Include built-in identifiers (default: false)

Resources

The server provides three resources for accessing internal state:

ast://current

Current parsed AST state with metadata and statistics.

ast://analysis

Results from the most recent code analysis (functions, classes, imports).

ast://transforms

History of code transformations and available operations.

Pattern Syntax

Tree-hugger-js uses intuitive patterns instead of verbose tree-sitter node types:

Basic Patterns

• function - Any function (declaration, expression, arrow, method)

• class - Class declarations and expressions

• string - String and template literals

• import/export - Import/export statements

• call - Function calls

• loop - For, while, do-while loops

Attribute Selectors

• [name="foo"] - Nodes with specific name

• [async] - Async functions

• [text*="test"] - Nodes containing text

CSS-like Selectors

• class method - Methods inside classes

• function > return - Return statements directly in functions

• :has() and :not() pseudo-selectors

Examples

Basic Code Analysis

Code Refactoring

Pattern Matching

Development

Error Handling

The server provides detailed error messages and suggestions:

• File not found errors for invalid file paths

• Parse errors with helpful context

• Pattern matching errors with suggestions

• Transformation errors with rollback capability

License

MIT