# error

## nominal.experimental.extractor.decorators.error(exception_type, *, code, exit_code, retryable=False, message=None)

Declare a structured failure handled by the extractor runner.

Place below `@manifest_extractor` or `@single_file_extractor`, alongside `@input`
and `@parameter`. Stack declarations for different Exception subclasses; the closest
class in the raised exception’s MRO wins, regardless of decorator order. Declaring the
same class twice is an error. This decorator preserves the callback’s signature.

`code` is a nonempty catalog error code; `exit_code` is an integer from 1 through 255.
`retryable` describes whether another attempt may succeed without changing the input.
Codes must fit the 4,096-byte termination JSON envelope. Long messages are shortened;
mapped failures retain their full traceback on stderr.

Mappings cover startup, argument binding, extraction, and output finalization. They
configure runtime reporting. `message` optionally supplies static fallback text for both
`Extractor.registration_kwargs()` and `Extractor.catalog_manifest()`; when omitted,
the code supplies a readable fallback truncated to 512 characters.
Runtime messages come from the exception. Both exports validate and combine exit-code fallbacks.
`run(exit=False)` and direct callback invocation propagate errors without reporting.

Return type:
:   *_ErrorMapping*