MCP servers

The Model Context Protocol (MCP) lets agents use tools from other programs, such as GitHub, a database or a game engine. In Jennefer the Engine runs your MCP servers on this computer, and you choose which ones agents may use: per chat in the IDE, per folder in the CLI and CLI+.

Add servers#

Add a server with a form, or paste a JSON config in the format Claude Desktop, VS Code and most server READMEs use.

1. 1

   Open Hub > Settings

   Scroll to MCP servers. In the IDE, Add a server or Manage in the chat's MCP menu opens the same place. In the CLI, /mcp hub opens it.

2. 2

   Fill in the form

   Choose Add server. Enter a Name, the Command (you can paste a whole command line), the Arguments one per row, and any Environment variables such as API keys. Working folder and Project folder are optional.

3. 3

   Or paste a config

   Choose Paste JSON and paste a config with an mcpServers object, a VS Code servers object, or the servers on their own. Choose Add servers. The Hub says which servers it added. Servers with a name you already use are skipped.

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": { "GITHUB_PERSONAL_ACCESS_TOKEN": "<your token>" }
    }
  }
}

Status and controls#

• Each server shows its status: Running, Starting, Error, Starts on first use or Off, with its number of tools and its command line.
• Use the switch to turn a server on or off, Restart to start it again, Edit to change it, or Remove to delete it.
• A server starts the first time an app needs its tools, and stops when the Engine stops. Opening the list does not start any server.
• Edit opens the same form with the server's settings. Save it to apply the change.

Use MCP in an IDE chat#

Under the chat box, next to the team chip, choose MCP. Tick the servers this chat may use under MCP servers in this chat. The button then shows how many tools agents have.

• The choice is kept per chat.
• Only selected servers that are running give tools to agents.
• MCP works for the whole team and for a single agent.

Project folders#

Some servers work on files outside your open project, for example a game engine project. Choose the folder icon next to a server in the MCP menu to set a folder for this chat. Without one, the server's projectFolder from the config is used.

Use MCP in the CLI and CLI+#

• /mcp lists your servers and which ones agents use in this folder.
• /mcp <name> turns a server on or off for this folder. /mcp <name> on or off sets it directly.
• Every tool call asks you first, and plan mode never uses MCP tools.

Approvals#

Every MCP tool call asks first: the agent wants to use an MCP tool. Allow it? The card shows the server and tool.

Using files in a folder outside the project has its own approval. See Approvals and safety.

FAQ#