Report what diff data is available between two versions of a terminology.
For most terminologies this is **guidance only** — the server doesn't ship historical snapshots, so the tool points at the publisher's official changelog and explains the cadence. `bundled_versions` lists the version(s) this server actually has on hand.
For **ICD-10 vs ICD-11** specifically, the tool surfaces a real cross-revision summary from the bundled WHO transition tables (the ICD-10 → ICD-11 case is a structural diff between two WHO revisions). Use `terminology: "icd10"` with no `to_version` to get the cross-revision summary: total mapped ICD-10 categories, how many are 1:1 vs split into multiple ICD-11 codes, and the average number of alternatives when split.
Inputs:
- `terminology` (required): which terminology to report on.
- `from_version` (optional): the version you have data from. If omitted, the tool reports against the currently-bundled version.
- `to_version` (optional): the version you want to compare to. If omitted, the tool reports against the publisher's latest known release.
This tool is intentionally a metadata + guidance layer, not a diff engine — for terminologies that change frequently (SNOMED, LOINC, RxNorm, MeSH), the publisher's official changelog is the authoritative source.