BetterDB MCP

Instructions

Implementation Reference

• packages/mcp/src/index.ts:180-198 (handler)

  The implementation of the `select_instance` tool, which verifies the instance ID against available instances and sets the global `activeInstanceId` variable.

  server.tool(
    'select_instance',
    'Select which instance subsequent tool calls operate on.',
    { instanceId: z.string().regex(/^[a-zA-Z0-9_-]+$/, 'Invalid instance ID format').describe('The instance ID to select') },
    async ({ instanceId }) => {
      const data = await apiFetch('/mcp/instances') as { instances: Array<{ id: string; name: string }> };
      const found = data.instances.find((inst) => inst.id === instanceId);
      if (!found) {
        return {
          content: [{ type: 'text' as const, text: `Instance '${instanceId}' not found. Use list_instances to see available instances.` }],
          isError: true,
        };
      }
      activeInstanceId = instanceId;
      return {
        content: [{ type: 'text' as const, text: `Selected instance: ${found.name} (${instanceId})` }],
      };
    },
  );