DEFINITION

HMR

Hot Module Reload

Definition

A development technique that allows code changes to be reflected in a running application without restarting the entire process or losing application state. In MCP development, HMR uses protocol primitives (e.g., tools/list_changed notifications) to reload tool definitions while maintaining the active MCP session.

Examples in the Wild

  • Example 1:Vite HMR for UI changes in MCP inspector
  • Example 2:MCP protocol-based HMR using tools/list_changed notifications
  • Example 3:Next.js and Vite HMR in web development frameworks