MCP servers

MCP (Model Context Protocol) servers give Mel's agent extra tools: a browser it can drive, your Docker or Kubernetes setup, documentation lookups, your own scripts. Mel can run servers on your computer (stdio) or reach servers on the web (Streamable HTTP), and every call to one stops for your approval. This page is about servers Mel uses. To use Mel from another app, see Use Mel from other apps.

Featured servers

Settings ▸ Library lists servers Mel has tested, each at the version Mel tested (Context7 is a hosted service and Docker uses your own Docker Desktop's):

Playwright · Chrome DevTools · Context7 · Docker · Terraform · Grafana · Kubernetes

Each starts off. Turn one on. Grafana also needs its service-account token and its URL; for the others a key is optional (Context7's API key raises its limits, an HCP Terraform token reaches your workspaces). Keys go to your keychain and are never put in a server's command line. A featured server missing something it needs says what, before any approval card.

Add your own server

Three ways:

• Settings ▸ Connectors ▸ Custom server…: a name, a command, its arguments (one per line) and its environment (KEY=value, one per line). Values are stored on this computer the way your API keys are.
• Settings ▸ Library ▸ Import ▸ Paste…: paste an mcpServers JSON block, the format other MCP apps use. ${VAR} in an entry is read from your shell's environment.
• A file: ~/.mel/mcp.json for you (on Windows, %APPDATA%\mel\config\mcp.json), or <repo>/.mel/mcp.json for a project.

{
  "mcpServers": {
    "my-tools": { "command": "node", "args": ["server.js"] },
    "docs-search": { "url": "https://example.com/mcp" }
  }
}

Safety

• Every call stops for your approval. A call to an MCP tool always shows an approval card listing its arguments, and offers no "always allow". With nobody at the computer, the call is refused.
• Imported and shared servers start off. A pasted server, or one from a project's or a team's mcp.json, is a program this computer would run, so it stays off until you turn it on. If its entry changes later, it is off again.
• Shared files hold names, not secrets. A project's or team's mcp.json that contains a secret value is refused. An import moves secret values to your keychain and keeps only their names.
• What a server returns is data. Its results reach the model marked as outside content, never as instructions.

How servers run

A server on your computer is started when a conversation first uses it and stays up for that conversation, then closes after 10 minutes idle or when the conversation ends. If it restarts, Mel says so.

Troubleshooting

The agent says a server is off. Turn it on in Settings ▸ Library. Only you can turn a server on.

A server fails to start. The error names the cause, for example a missing command or a missing key.

I changed mcp.json and nothing happened. The next turn picks up the change.

FAQ

What's the difference between an MCP server and a connector? A connector is a partner service Mel offers ready to connect with your own key (GitHub, Slack, Linear and others). An MCP server is any server you add yourself, or one of the featured ones.

Do MCP servers work in VS Code? Yes. The VS Code extension uses the Mel app's Library, so the servers you turned on there are available.