Free
A registry key to the substance record and its crossrefs.
Connect substance_lookup to your agentWhat it answers
Look up one substance by its registry key and get the preferred term with the crossrefs the registry itself publishes. Those crossrefs are the registry's claim rather than a join citature performed, and the receipt says which. A key that is not in the registry returns a null answer with a citation, not an error.
Ask it things like
- What substance is UNII 1406-16-2?
- What is the RxCUI for this substance?
- Which plant does this substance come from?
What comes back
A receipt, and the same envelope on every tool — so a caller writes against one contract whichever one they call. The citations carry two clocks that are never collapsed: citature's retrieved_at and the source's own as_of, plus the record's own published_at and record_version where the source publishes them.
Answer
citature — substance_lookup receipt
- answer
- The rows themselves, typed per tool. Amounts carry their unit and their basis, because a figure per serving and one per 100 g are not comparable.
- citations
- The record behind the answer: a re-runnable upstream URL, citature's retrieval clock, the release's own currency date, and the record's own version.
- coverage
- What this answer does not reach, and where the record is silent rather than negative.
- guardrails
- The standing caveats, shipped in the answer itself rather than only on a page an agent never loads.
- matches
- Every join the answer used, named by method and confidence. A name match is reported as a name match, never as an identity.
- schema_version
- The conformed schema the answer was produced against, so a caller can pin it.
What this figure is
Input
| param | type | required | notes |
|---|---|---|---|
| unii | string | yes | Ten-character registry key. |
Sources
Primary federal records only, never an aggregator. This answer's citations name:
- unii
Pricing
Free — this answer restates a public record, so it carries no meter at all.
Connect substance_lookup to your agentguardrails & coverage
- Research over public records and product labels — not medical, nutritional, or safety advice.
- citature reports what the record says. It never renders a verdict, a pass/fail, a diagnosis, or a recommendation, and is not a substitute for a clinician.
- Answers are product-, substance- or population-level only — foods, supplements, labels, substances, enforcement actions, and dietary intake as a weighted survey estimate. No answer returns or describes an individual person, and citature links no record to individually identifiable data.
- A record that does not declare something is not a record declaring its absence. citature reports what a record states; it cannot report what a product does not contain, or what a population did not consume.
- A Daily Value is a labelling reference from federal regulation, not a Dietary Reference Intake. citature carries no licensed source for Dietary Reference Intakes and does not estimate whether anyone meets a nutrient requirement.
- Coverage reflects the records citature has ingested, not the full upstream history. Each dataset advances when its source publishes a release.
- Every answer states its own coverage caveats in the receipt's `coverage` field, alongside these standing guardrails.