MCP Server

The Asterism MCP server enables Claude Code, Cursor, and other MCP-compatible AI assistants to load and use skills from the registry.

What is MCP?

The Model Context Protocol (MCP) is a standard for providing context and tools to AI assistants. The Asterism MCP server exposes registry skills as MCP tools, allowing your AI assistant to search, load, and use skills dynamically.

Installation

The MCP server runs via npx, so no installation is required. Just configure your AI assistant to use it.

Claude Code Configuration

Add the following to your ~/.claude/mcp.json:

{
  "mcpServers": {
    "aster": {
      "command": "npx",
      "args": ["-y", "astermcp"],
      "env": {
        "ASTER_API_KEY": "aster_live_xxxx"
      }
    }
  }
}

Get your API key from the dashboard. The API key is optional for public skills but required for private skills.

Cursor Configuration

Add to your Cursor MCP settings (Settings → MCP → Add Server):

Command: npx
Args: -y astermcp
Environment: ASTER_API_KEY=aster_live_xxxx

Available Tools

Once configured, your AI assistant will have access to these tools:

ask_search

Search the registry for skills matching a query.

ask_load

Load a skill's SKILL.md content into the conversation context.

ask_file

Load a specific file from a skill package.

ask_info

Get detailed metadata about a skill (author, version, downloads, security score).

ask_list

List popular or featured skills in the registry.

Environment Variables

Variable	Description	Default
ASTER_API_KEY	API key for private skills	-
ASTER_REGISTRY_URL	Custom registry URL	api.joinasterism.com
ASTER_CACHE_TTL	Cache TTL in seconds	3600
ASTER_DEBUG	Enable debug logging	false

Usage Example

Once configured, you can ask your AI assistant to use skills:

"Search for PDF tools and load the best one"

The assistant will use ask_search to find relevant skills, then ask_load to bring the skill's instructions into the conversation.

Troubleshooting

Server not starting

Make sure Node.js 18+ is installed and npx is available in your PATH.

Authentication errors

Verify your API key is correct and not expired. Generate a new one from the dashboard if needed.

Skills not loading

Enable debug mode (ASTER_DEBUG=true) to see detailed logs.