MCP Servers Validator

The MCP validator checks .mcp.json configuration files for transport types, URLs, environment variables, and server configuration.

What It Checks

• Transport type validity (stdio, SSE, HTTP, WebSocket)
• URL format validation per transport type
• Environment variable syntax
• Variable expansion patterns
• Command validation for stdio transport

Rules

This validator includes 11 rules. See the MCP rules category for the complete list.

mcp-invalid-transport

Unknown or invalid MCP transport type

Error

mcp-stdio-empty-command

Stdio transport is missing the command field

Error

mcp-http-invalid-url

HTTP transport URL is malformed or invalid

Error

mcp-invalid-env-var

Environment variable name is invalid

Warning

CLI Usage

claudelint validate-mcp
claudelint validate-mcp --verbose

Plugin Skill

If you have the claudelint plugin installed, you can run this validator inside Claude Code with /validate-mcp or by asking "Validate my MCP config."

See Also

• Claude Code MCP Servers - Official MCP documentation
• Configuration - Customize rule severity