Type Alias ExpressMiddleware

ExpressMiddleware: (
    req: express.Request,
    res: express.Response,
    next: express.NextFunction,
) => Promise<void>

An Express middleware function to mount before the MCP route handler. Standard use-cases include authentication, request logging, and rate limiting.

Type Declaration

- (
      req: express.Request,
      res: express.Response,
      next: express.NextFunction,
  ): Promise<void>
- Parameters
  - req: express.Request
  - res: express.Response
  - next: express.NextFunction
  Returns Promise<void>

Example

const authMiddleware: ExpressMiddleware = async (req, res, next) => {
  if (!req.headers.authorization) {
    res.status(401).json({ error: 'Unauthorized' })
    return
  }
  await next()
}