Retrieve an assessment

Retrieves a single assessment’s metadata.

Any published assessment is readable. A paper you created is readable in every
status, so you can poll it through extraction and review — this is also how you
recover a state webhook you never received.

Returns

id, code, name, assessment_type, status, external_reference, subject, topics, question_count, questions_needing_review, total_marks, has_solutions_document, answer_key_quality, and an extraction object carrying failure_reason when extraction failed. answer_key_quality.clean must be true before publication.