Returns the verified migration map for upgrading a package between two versions: ordered breaking changes with before/after code, deprecations, source-citation URLs, and a last_verified date. Accepts concrete versions or SemVer ranges (e.g. "^14.2.0", "~14.1.0", "15.x"); non-exact lookups resolve to the covering map and disclose how via match_type/resolved_via/match_note. If found=false, no verified data exists — do not guess.

Returns the breaking changes introduced when upgrading TO the given version of a package (matched by major version against curated migration maps), with source citations and last_verified dates. Accepts concrete versions or SemVer ranges ("15", "^15.0.0", "15.x"); resolution is disclosed via match_type/resolved_via. If found=false, no verified data exists — do not guess.

Lists every migration map in the store: package, ecosystem, from_version, to_version, status (draft/verified/stale), last_verified. Optional filters: ecosystem, package. Use this to discover coverage before calling get_migration.

Static SemVer check of two known package versions against curated compatible_with peer data from migration maps. Purely declarative — no filesystem access or project inspection (that is the scope of the separate, unimplemented check_compatibility). Returns compatible: true | false | "unknown". Treat "unknown" as absence of curated data, never as evidence of incompatibility.

PLANNED: project-aware compatibility analysis. Currently returns implemented=false and no data. Do not infer compatibility (or incompatibility) from this response. For a static SemVer check between two known package versions, use check_peer_compatibility instead.