- emptyResultMessage(skip, baseHint) in format-utils disambiguates "no matches" from "paginated past the end" — openFDA returns 404 for both. Adopted across all six search/lookup tools.
- OpenFdaService caches meta.last_updated per endpoint and reuses it on subsequent 404s; 404 responses also preserve the request's skip/limit instead of zeroing them.
- formatRemainingFields rewritten around a renderValue helper: string arrays comma-join, single-level objects flatten to key=value pairs, deeper structures fall back to JSON, empty containers skip cleanly.
- openfda_search_adverse_events drug section skips FDA workflow timestamps and format codes; openfda_search_device_clearances renders advisory_committee alongside its description.
- Description polish across the surface: corrected sort-failure note from "silently ignored" to "query error"; added cross-tool pairing hints (count, lookup_ndc, search_drug_approvals); expanded output results schemas with concrete field inventories.
- Two new tests cover the 404 skip/limit preservation and cached lastUpdated fallback.