ReferenceError codes

adapter_not_found

A runtime route name does not match a registered adapter.

EmailAdapterNotFoundError has code adapter_not_found, is not retryable, and exposes the missing adapter string.

Literal route names normally fail type checking. This error remains necessary for values that enter from untyped configuration, JSON, plugin code, or other runtime boundaries.

src/send.ts

if (error instanceof EmailAdapterNotFoundError) {
  console.error(error.adapter);
}

List registered routes through email.adapters or run email-sdk adapters for bundled CLI names.

validation_error

The message, route, schedule, capability, or adapter-specific input is invalid before dispatch.

adapter_error

One adapter or transport failed with explicit retryability and delivery certainty.