%23%23 Description%0A%0AWhen using the Cowork plugin customizer skill to package a plugin%2C the output file is given a %60.plugin%60 extension. However%2C the Claude desktop app%27s plugin upload dialog only accepts %60.zip%60 files. This mismatch prevents users from uploading the packaged plugin directly.%0A%0A%23%23 Steps to Reproduce%0A%0A1. Use the Cowork plugin customizer skill to customize and package a plugin%0A2. The skill outputs a %60.plugin%60 file%0A3. Open the Claude desktop app and navigate to the plugin upload dialog%0A4. Attempt to upload the %60.plugin%60 file%0A5. Upload fails %E2%80%94 the dialog only accepts %60.zip%60 files%0A%0A%23%23 Expected Behavior%0A%0AEither%3A%0A-% The plugin customizer skill should output a %60.zip%60 file %28or both%29%2C OR%0A-% The desktop app upload dialog should accept %60.plugin%60 files%0A%0A%23%23 Actual Behavior%0A%0AThe packaged file has a %60.plugin%60 extension but the upload dialog requires %60.zip%60%2C forcing users to manually rename the file before uploading.%0A%0A%23%23 Environment%0A%0A- Claude desktop app %28Cowork mode%29