Find observed rows from legislative change feeds in a jurisdiction or framework, or from an explicit source. Use this for questions such as 'what laws changed in Sweden this month' only when the requested scope is listed as amendment-capable. If since is omitted, the gateway defaults to the last 90 days. Coverage is per corpus. The EU Regulations source is baseline-only during the current interim: it is excluded from amendment-capable dispatch, and a framework it owns is advertised only if another reachable feed supports that framework. A successful empty response is not evidence that no amendments occurred. On a capability miss, the response names supported source, framework, and jurisdiction scopes — or, when no corpus advertises change feeds at all, says so explicitly with supported_scopes empty on every axis. Every dispatched response reports whether baseline rows were actually withheld and whether the producer supplied typed event metadata. Legacy rows without typed event metadata remain visible with event_kind unknown. A scope value that names nothing we serve is refused, not ignored: the call errors and names the value, never returning changes for only the part that resolved. Use diff for a known provision. Boundary: this tool reports amendments observed in SERVED corpus text; for newly published official acts and regulator announcements (what is new, not what changed in a text we serve), use search_regulatory_updates. The text content is one JSON document. Its evidence_summary field carries the 'Sources used' markdown table (the audit receipt per returned row) or a labelled zero-result note. Result rows carry url/title/subtitle display fields alongside their citation when available. meta.render_contract carries the versioned evidence-curation contract.