Mastra.listMCPServers()

The .listMCPServers() method is used to retrieve all MCP server instances that have been registered in the Mastra instance. The returned record uses registry keys (the keys from the mcpServers configuration) as keys.

Usage example

// Register MCP servers
const server1 = new MCPServer({
  id: 'server-one',
  name: 'Server One',
  version: '1.0.0',
  tools: { /* ... */ },
});

const server2 = new MCPServer({
  id: 'server-two',
  name: 'Server Two',
  version: '1.0.0',
  tools: { /* ... */ },
});

export const mastra = new Mastra({
  mcpServers: {
    firstServer: server1,   // Registry key: 'firstServer'
    secondServer: server2,  // Registry key: 'secondServer'
  },
});

// List all registered servers
const servers = mastra.listMCPServers();
// Returns: { firstServer: MCPServerBase, secondServer: MCPServerBase }

Parameters

This method does not accept any parameters.

Returns

servers:

Record<string, MCPServerBase> | undefined

A record of all registered MCP server instances, where keys are the registry keys (from mcpServers configuration) and values are MCPServerBase instances, or undefined if no servers are registered.

Related Methods

• Mastra.getMCPServer() - Retrieve an MCP server by its registry key
• Mastra.getMCPServerById() - Retrieve an MCP server by its intrinsic id property

See Also

• MCP overview
• MCP server reference