MCP Server User Configuration Support

What: Plugins can now request user-provided configuration values (API keys, paths, settings) through structured schemas defined in their manifest files.

How to use:

# When adding a plugin that requires configuration:
claude mcp add my-plugin

# If the plugin has user_config requirements, you'll see:
# Configure my-plugin server
# Field 1 of 3: API Key
# [Enter your value]

# Or configure an existing plugin:
claude mcp configure my-plugin server-name

Details:

• Plugins define user_config schemas in manifest.json with field types (string, number, boolean, file, directory)
• Interactive CLI prompts collect configuration values with validation
• Sensitive fields (API keys, tokens) are masked during input
• Configuration persisted to ~/.claude/userSettings.json under pluginConfigs
• Server configs support variable substitution using ${user_config.fieldName} syntax
• Validation ensures required fields are provided and types match schema
• Evidence: CF1() at line 280192, q7B() at line 280048, fOQ() at line 447320