LINE MCP Server

English | 日本語

Model Context Protocol (MCP) server for LINE messaging integration with AI assistants.

Overview

LINE MCP Server is a Model Context Protocol server that integrates LINE messaging services with AI assistants like Claude Desktop. It enables AI assistants to authenticate, manage contacts, and send messages through LINE accounts.

Key Features

• LINE Login: LINE authentication using environment variables
• Contact Management: Contact retrieval with search and token optimization features
• Message Sending: Send messages to LINE users (via MID)
• Smart Search: Response optimization with token limits
• Login State Management: Authentication state and error handling

Target Users

For General Users

Perfect for those who want to use LINE messaging features with Claude Desktop. AI assistants can help with:

• Searching and managing LINE contacts
• Sending messages to specific people
• Retrieving and organizing contact information

For AI Assistant Users

This server enables AI assistants to:

• Login to LINE accounts
• Search and filter contact lists
• Send messages to specified contacts
• Check and manage login status

Technical Specifications

Available Tools

1. login

Description: Login to LINE using command line arguments

Parameters: None

2. get_contacts

Description: Get contacts with optional search filter and token limits

Parameters:

• search (optional, string): Search filter by contact name
• maxTokens (optional, number): Token limit for response

3. send_message

Description: Send message to specified user

Parameters:

• to (required, string): Recipient's MID
• message (required, string): Message to send

Setup

Command Line Arguments

The LINE MCP server requires three command line arguments:

1. EMAIL: Your LINE account email address
2. PASSWORD: Your LINE account password
3. STORAGE_PATH: Directory path where authentication tokens will be stored

Syntax: npx line-mcp <email> <password> <storage_path>

Example: npx line-mcp user@example.com mypassword ./line_storage

Important: The storage directory must exist before starting the server. If the specified path does not exist or is not accessible, the server will fail to start.

Claude Desktop Configuration

Add the following configuration to your claude_desktop_config.json file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

Basic Configuration

{
  "mcpServers": {
    "line-mcp": {
      "command": "npx",
      "args": ["line-mcp", "your_line_email@example.com", "your_line_password", "/path/to/storage/directory"]
    }
  }
}

Advanced Configuration with Working Directory

You can also specify a working directory (cwd) for the MCP server. This is useful when using relative paths or when you want to set a specific base directory for the server's operations:

{
  "mcpServers": {
    "line-mcp": {
      "command": "npx",
      "args": [
        "line-mcp@latest",
        "your_line_email@example.com", 
        "your_line_password",
        "./line_auth_storage"
      ],
      "cwd": "/path/to/your/project/directory"
    }
  }
}

Configuration Options:

• command: The command to execute (usually npx)
• args: Array of command line arguments including package name, email, password, and storage path
• cwd (optional): Working directory for the MCP server execution. When specified, relative paths in the arguments will be resolved relative to this directory.

Important:

• Replace your_line_email@example.com and your_line_password with your actual LINE account credentials.
• Replace the storage path with the directory or file where authentication tokens will be stored.
• The storage directory must exist: If the specified storage path does not exist, the server will fail to start with an error.
• When using cwd, you can use relative paths like ./line_auth_storage for the storage path, which will be resolved relative to the specified working directory.

Dependencies

Main dependencies:

• @evex/linejs: LINE client library
• @modelcontextprotocol/sdk: MCP server development kit
• tiktoken: Token counting
• zod: Schema validation
• dotenv: Environment variable management

Security Considerations

Access Control

• This server provides full access to your LINE account
• Use only in trusted environments
• Regularly check your LINE account login history

Troubleshooting

Common Issues

1. Cannot Login

Symptoms: Error occurs with login tool Solutions:

• Check if command line arguments (email and password) are correctly set in Claude Desktop configuration
• Verify LINE account is valid and using correct credentials
• Consider using app password if 2FA is enabled

2. Cannot Get Contacts

Symptoms: get_contacts tool returns empty results Solutions:

• First check login status with status_login
• If not logged in, run login tool
• Check if contacts are synced in LINE app

3. Cannot Send Messages

Symptoms: Error occurs with send_message tool Solutions:

• Verify recipient's MID is correct (can be obtained via get_contacts)
• Check login status
• Verify LINE account is not under message sending restrictions

4. Server Fails to Start

Symptoms: Server fails to initialize or start Solutions:

• Verify the storage directory path exists and is accessible
• Check directory permissions (read/write access required)
• Ensure all three command line arguments are properly specified in Claude Desktop configuration
• Create the storage directory manually if it doesn't exist

Limitations

• Currently supports only text message sending (images, files etc. not supported)
• Group chat functionality not implemented
• Use in accordance with LINE's terms of service and API limitations

License

MIT License

Contributing

Pull requests and issue reports are welcome.

Support

If you encounter issues, please check:

1. Command line arguments configuration in Claude Desktop
2. LINE account status
3. Network connection
4. Claude Desktop configuration

For additional support, please create an issue.