There is no cordova plugin add in a Capacitor 243,123 project. A Cordova 129 plugin is an npm 2,036 package, installed like any other and picked up by the next sync:
npm install cordova-plugin-dialogs
npx cap sync androidIn the migrated notes app the three plugins were already in package.json, put there by cordova plugin add, so adding Capacitor was enough. After npm install @capacitor/core @capacitor/cli @capacitor/android and npx cap init BookNest com.example.booknest.legacy --web-dir www, adding the platform found them:
$ npx cap add android
...
[info] Found 3 Cordova plugins for android:
cordova-plugin-device@3.0.0
cordova-plugin-dialogs@2.0.2
cordova-plugin-geolocation@5.0.0
...
[success] android platform added!The app ran unchanged: index.html still loads cordova.js, deviceready still fires, and device reported the same model string. For TypeScript types, the Awesome Cordova Plugins project (@awesome-cordova-plugins/*) publishes typed wrappers for common Cordova plugins.