Generate API reference from this code

A module whose public surface needs documenting properly, not just typed.

Produce reference documentation for the public API in the code below.

For each exported function, class, or endpoint:
- **Signature**, exactly as callers see it
- **What it does**, one sentence, starting with a verb
- **Parameters**: name, type, required or optional, default, and what an invalid value does
- **Returns**: type and shape, including what is returned on the empty or no-match case
- **Throws or errors**: every error condition, with the exact error type or status code
- **Example**: a realistic call with realistic values, never `foo` and `bar`
- **Notes**: side effects, idempotency, rate limits, whether it mutates its arguments

Document only what is exported. Do not document internals. Where the code does not make a behaviour clear (error cases, nullability, ordering guarantees), list it as an open question rather than guessing.

Code:

Reference and API docs. The lookup layer: function docs, config options, error codes and examples worth copying.