Arca MCP Server

Model Context Protocol (MCP) server for the Arca API. Enables Claude Desktop and other MCP-compatible LLMs to interact with your Arca workspaces, tasks, lists, folders, and comments.

Features

• Workspaces: List and get workspace details

• Tasks: List, create, update, delete, and get task details

• Lists: List, create, update, and delete lists

• Folders: List, create, update, and delete folders

• Comments: List and create comments on tasks

• Statuses: List, create, update, and delete workspace statuses

• Labels: List, create, update, and delete workspace labels

All operations use your personal Arca API key to authenticate directly with the Arca API.

Related MCP server: Todoist MCP Server

Installation

Quick Setup (Recommended)

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "arca": {
      "command": "npx",
      "args": ["-y", "arca-mcp"],
      "env": {
        "ARCA_API_KEY": "arca_your_api_key_here"
      }
    }
  }
}

Get your API key from Settings → API Keys in the Arca app.

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

• Linux: ~/.config/Claude/claude_desktop_config.json

Then restart Claude Desktop to connect.

Build from Source

If you prefer to build locally:

git clone https://github.com/gredevelopment/arca-mcp.git
cd arca-mcp
npm install
npm run build

Update your Claude Desktop config to use the local build:

{
  "mcpServers": {
    "arca": {
      "command": "node",
      "args": ["/absolute/path/to/arca-mcp/build/index.js"],
      "env": {
        "ARCA_API_KEY": "arca_your_api_key_here"
      }
    }
  }
}

Usage

Once connected, you can ask Claude to interact with your Arca workspace:

• "List all my Arca workspaces"

• "Show me tasks in the [workspace name] workspace"

• "Create a task called 'Review PR' in the Development list"

• "Update task #42 to high priority"

• "Add a comment to task #42: 'Looks good to merge'"

Available Tools

Workspaces

• list_workspaces - List all workspaces you have access to

• get_workspace - Get detailed information about a specific workspace

Tasks

• list_tasks - List tasks in a workspace (optionally filtered by list)

• get_task - Get detailed information about a task

• create_task - Create a new task

• update_task - Update task properties (title, description, status, priority, dates)

• delete_task - Delete a task

Lists

• list_lists - List all lists in a workspace (optionally filtered by folder)

• create_list - Create a new list

• update_list - Update list properties

• delete_list - Delete a list

Folders

• list_folders - List all folders in a workspace

• create_folder - Create a new folder

• update_folder - Update folder properties

• delete_folder - Delete a folder

Comments

• list_comments - List all comments on a task

• create_comment - Add a comment to a task

Statuses

• list_statuses - List all statuses in a workspace

• create_status - Create a new status (owner/admin only)

• update_status - Update status properties (owner/admin only)

• delete_status - Delete a status, optionally reassigning tasks (owner/admin only)

Labels

• list_labels - List all labels in a workspace

• create_label - Create a new label

• update_label - Update label properties (owner/admin only)

• delete_label - Delete a label (owner/admin only)

How It Works

1. The MCP server runs locally on your machine via npx

2. It authenticates to the Arca API using your personal API key

3. Claude Desktop communicates with the server via STDIO (standard input/output)

4. All data stays between your machine and Arca's API - no third-party servers involved

Smart Tool Chaining

The server includes built-in instructions that guide LLMs to make intelligent multi-step decisions. For example:

Instead of saying: "I can't list tasks by workspace name, only by ID"

The LLM will automatically:

1. Call list_workspaces to find the workspace ID from the name

2. Use that ID to call list_tasks

3. Return the results seamlessly

This works for common patterns like:

• "Show tasks in My Project workspace" → Resolves workspace name to ID automatically

• "Create a task in Development workspace" → Finds workspace, optionally suggests statuses

• "Update the 'Fix bug' task" → Searches for task by title, then updates it

The server instructions are registered as an MCP prompt (server_instructions) that LLMs can reference, plus enhanced tool descriptions that encourage smart workflow patterns.

Requirements

• Node.js 16 or higher

• An Arca account with API access

• Claude Desktop (or another MCP-compatible client)

Security

Your API key is stored locally in the Claude Desktop config and never leaves your machine except to authenticate with the official Arca API (https://api.getarca.app).

Support

For issues or questions:

• GitHub Issues: https://github.com/gredevelopment/arca-mcp/issues

• Arca Support: https://getarca.app/support

License

ISC License - see LICENSE file for details.