backup config files before overwriting

Author: njayp

src/platform/base.ts

@@ -1,5 +1,5 @@
-import { readFile, writeFile, mkdir } from 'fs/promises';
-import { dirname } from 'path';
+import { readFile, writeFile, mkdir, copyFile, stat } from 'fs/promises';
+import { dirname, join } from 'path';
 
 /**
  * Base interface that all MCP config formats must implement.
@@ -92,10 +92,28 @@ export abstract class ConfigManager<T extends MCPConfig, S = unknown> {
     const wasEnabled = this.serverName in servers;
     const serverConfig = this.createServerConfig(baseUrl, apiToken);
     servers[this.serverName] = serverConfig;
+    await this.createBackup();
     await this.writeConfig(config);
     return wasEnabled;
   }
 
+  async createBackup(): Promise<void> {
+    try {
+      await stat(this.configPath);
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code === 'ENOENT') {
+        return;
+      }
+      throw error;
+    }
+
+    const timestamp = new Date().toISOString().replace(/[:.]/g, '-');
+    const dir = dirname(this.configPath);
+    const backupPath = join(dir, `mcp.backup.${timestamp}.json`);
+
+    await copyFile(this.configPath, backupPath);
+  }
+
   /**
    * Disable the server configuration.
    * @returns true if the server was enabled and has been disabled, false if it was not enabled