claude-code - 💡(How to fix) Fix [FEATURE] Allow customizing MCP server args for plugin-installed MCPs [1 comments, 2 participants]

{                                                                                                                                                             
  "enabledPlugins": {                                                                                                                                         
    "chrome-devtools-mcp@chrome-devtools-plugins": {                                                                                                          
      "enabled": true,                                                                                                                                        
      "extraArgs": ["--autoConnect"],                                                                                                                         
      "extraEnv": { "PORT": "9222" }                                                                                                                          
    }                                                                                                                                                         
  }                                                                                                                                                           
}                                                                                                                                                             
                                                                                                                                                              
- extraArgs: appended to the args defined in plugin.json                                                                                                      
- extraEnv: merged into the env defined in plugin.json                                                                                                        
- Non-breaking: existing "pluginName": true shorthand still works                                                                                             
                                                                                                                                                              
Option B: Let .mcp.json merge with plugin-defined MCPs                                                                                                        
                                                                                                                                                              
If a plugin registers an MCP server named chrome-devtools and the user also defines chrome-devtools in .mcp.json, merge the user's config on top of the       
plugin's config. User-defined args/env take precedence.                                                                                                       
                                                                                                                                                              
Option C: Add a warning when .mcp.json conflicts with a plugin                                                                                                
                                                                                                                                                              
At minimum, if a user defines an MCP server in .mcp.json that shares the same name as a plugin-installed MCP, show a warning:                                 
                                                                                                                                                              
⚠ MCP server "chrome-devtools" is also defined by plugin                                                                                                      
  "chrome-devtools-mcp@chrome-devtools-plugins".                                                                                                              
  The plugin config takes precedence.                                                                                                                         
                                                                                                                                                              
This alone would have saved me hours of debugging.

### Alternative Solutions

## Alternative Solutions

1. Manually edit plugin.json — This is what I currently do. I edit both ~/.claude/plugins/marketplaces/<marketplace>/.claude-plugin/plugin.json and
~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/.claude-plugin/plugin.json. The downside is that plugin updates overwrite these changes silently.
2. Uninstall the plugin and configure via .mcp.json instead — This works for the MCP server itself, but loses the plugin's bundled skills, guides, and agent
rules that are only available through the plugin system.

Neither alternative is satisfactory.

### Priority

High - Significant impact on productivity

### Feature Category

MCP server integration

### Use Case Example

## Use Case Example

1. I install chrome-devtools-mcp via the plugin system to get its bundled skills (a11y-debugging, troubleshooting, performance analysis, etc.)
2. I open Chrome with remote debugging enabled on my machine
3. I want chrome-devtools-mcp to connect to my existing browser session using --autoConnect, instead of launching a new browser
4. I add --autoConnect to my project's .mcp.json → Does not work. No error, no warning.
5. After hours of debugging, I discover .mcp.json is not read for plugin-installed MCPs
6. I manually edit two plugin.json files deep inside ~/.claude/plugins/ → Works, but fragile
7. Next plugin update → my changes are gone, back to step 4

### Additional Context

## Additional Context

- Environment: Claude Code on Windows 11, plugin chrome-devtools-mcp@chrome-devtools-plugins v0.21.0
- Root cause: The plugin system and .mcp.json are completely independent config paths. Plugin-installed MCPs are launched solely from plugin.json, and
.mcp.json entries for the same server name are silently ignored.
- Files involved:
  - ~/.claude/plugins/marketplaces/<marketplace>/.claude-plugin/plugin.json (marketplace source definition)
  - ~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/.claude-plugin/plugin.json (cached copy used at runtime)
  - ~/.claude/plugins/installed_plugins.json (installation registry)
  - {project}/.claude/settings.json → enabledPlugins (project-level enablement, no arg override support)
- This issue likely affects all plugin-installed MCPs where users need custom arguments, not just chrome-devtools-mcp.