Error reference

Condition	Result
Missing, non-string, or unknown action name	404 (NotFoundHttpException).
Selected registry value is not a valid class-string	LogicException; normally a server error.
Registered class does not exist	LogicException; normally a server error.
Unsupported HTTP method	405 (MethodNotAllowedHttpException), with Allow.
Invalid action_key or action_source configuration	LogicException; normally a server error.
Registered class does not implement ActionInterface	LogicException; normally a server error.
Action has no public handle()	LogicException; normally a server error.
Form request validation fails	Laravel's validation response; normally 422 for JSON.
Form request authorization fails	Normally 403.
Authentication or another middleware rejects the request	That middleware's response.

Send Accept: application/json when you want JSON errors. Exert uses your application's exception handling; it does not define a separate error envelope.

Read the error in context

A 404 means no applicable action name was found in the registry. Once an entry is selected, an invalid value, missing class, or incompatible class is reported as a configuration error instead.

A 405 can come from the outer Laravel route or from Exert's action method check. The route runs first. See HTTP methods for an example with two different method lists.

Server errors from invalid configuration are developer errors. Correct the key, source, mapping, or handler rather than adding a client retry.

Application errors stay application errors

Exert does not catch a failed business operation and turn it into success. Laravel's exception handler determines how application exceptions become responses. If your application customizes validation or authorization responses, the resulting JSON may differ from the examples here.

For common setup problems, use Troubleshooting.