diff --git a/web/src/app/api/discover/preview/[mbid]/route.test.ts b/web/src/app/api/discover/preview/[mbid]/route.test.ts
new file mode 100644
index 0000000..08e6eba
--- /dev/null
+++ b/web/src/app/api/discover/preview/[mbid]/route.test.ts
@@ -0,0 +1,54 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+
+vi.mock("@/lib/musicbrainz", () => ({ browseReleaseGroups: vi.fn(), getArtistName: vi.fn() }));
+import { browseReleaseGroups, getArtistName } from "@/lib/musicbrainz";
+import { prisma } from "@/lib/db";
+import { GET } from "./route";
+
+const mockBrowse = vi.mocked(browseReleaseGroups);
+const mockName = vi.mocked(getArtistName);
+afterEach(() => { mockBrowse.mockReset(); mockName.mockReset(); });
+
+function get(mbid: string, qs = "") {
+  return GET(new Request(`http://localhost/api/discover/preview/${mbid}${qs}`), {
+    params: Promise.resolve({ mbid }),
+  });
+}
+
+describe("discover preview API", () => {
+  it("annotates own-state, defaults to core releases, reports followed", async () => {
+    mockBrowse.mockResolvedValue([
+      { rgMbid: "rg1", title: "Studio", primaryType: "Album", secondaryTypes: [], firstReleaseDate: "2000" },
+      { rgMbid: "rg2", title: "Live One", primaryType: "Album", secondaryTypes: ["Live"], firstReleaseDate: "2001" },
+      { rgMbid: "rg3", title: "Owned", primaryType: "Album", secondaryTypes: [], firstReleaseDate: "2002" },
+      { rgMbid: "rg4", title: "Scanned", primaryType: "Album", secondaryTypes: [], firstReleaseDate: "2003" },
+    ]);
+    await prisma.watchedArtist.create({ data: { mbid: "a1", name: "Band" } });
+    await prisma.monitoredRelease.create({ data: { artistMbid: "a1", artistName: "Band", rgMbid: "rg1", album: "Studio", secondaryTypes: [], monitored: true } });
+    await prisma.monitoredRelease.create({ data: { artistMbid: "a1", artistName: "Band", rgMbid: "rg3", album: "Owned", secondaryTypes: [], monitored: false, currentQualityClass: 3 } });
+    await prisma.libraryItem.create({ data: { artist: "Band", album: "Scanned", path: "/x", source: "scan", format: "FLAC", qualityClass: 3 } });
+
+    const body = await (await get("a1", "?name=Band")).json();
+    expect(body.followed).toBe(true);
+    expect(body.artistName).toBe("Band");
+    expect(body.releases.map((r: any) => r.album)).toEqual(["Studio", "Owned", "Scanned"]); // Live excluded
+    expect(body.releases.find((r: any) => r.rgMbid === "rg1")).toMatchObject({ monitored: true, have: false });
+    expect(body.releases.find((r: any) => r.rgMbid === "rg3")).toMatchObject({ monitored: false, have: true });
+    expect(body.releases.find((r: any) => r.rgMbid === "rg4")).toMatchObject({ have: true }); // via LibraryItem
+    expect(mockName).not.toHaveBeenCalled(); // ?name= shortcut
+  });
+
+  it("?all=true includes non-core; missing ?name falls back to getArtistName; 502 on MB throw", async () => {
+    mockBrowse.mockResolvedValue([
+      { rgMbid: "rg2", title: "Live One", primaryType: "Album", secondaryTypes: ["Live"], firstReleaseDate: "2001" },
+    ]);
+    mockName.mockResolvedValue("Resolved");
+    const body = await (await get("a1", "?all=true")).json();
+    expect(body.releases.map((r: any) => r.album)).toEqual(["Live One"]);
+    expect(body.artistName).toBe("Resolved");
+    expect(body.followed).toBe(false);
+
+    mockBrowse.mockRejectedValue(new Error("down"));
+    expect((await get("a1")).status).toBe(502);
+  });
+});
diff --git a/web/src/app/api/discover/preview/[mbid]/route.ts b/web/src/app/api/discover/preview/[mbid]/route.ts
new file mode 100644
index 0000000..a293f8f
--- /dev/null
+++ b/web/src/app/api/discover/preview/[mbid]/route.ts
@@ -0,0 +1,51 @@
+import { prisma } from "@/lib/db";
+import { browseReleaseGroups, getArtistName } from "@/lib/musicbrainz";
+import { isCoreRelease } from "@/lib/release-filter";
+
+export async function GET(request: Request, { params }: { params: Promise<{ mbid: string }> }) {
+  const { mbid } = await params;
+  const url = new URL(request.url);
+  const nameParam = url.searchParams.get("name");
+  const showAll = url.searchParams.get("all") === "true";
+
+  let groups;
+  try {
+    groups = await browseReleaseGroups(mbid);
+  } catch {
+    return Response.json({ error: "MusicBrainz unavailable" }, { status: 502 });
+  }
+  const visible = showAll ? groups : groups.filter(isCoreRelease);
+
+  let artistName = nameParam?.trim() || "";
+  if (!artistName) {
+    try {
+      artistName = await getArtistName(mbid);
+    } catch {
+      artistName = "";
+    }
+  }
+
+  const followed = (await prisma.watchedArtist.findUnique({ where: { mbid } })) != null;
+
+  const rgMbids = visible.map((g) => g.rgMbid);
+  const albums = visible.map((g) => g.title);
+  const monitored = await prisma.monitoredRelease.findMany({ where: { rgMbid: { in: rgMbids } } });
+  const monMap = new Map(monitored.map((m) => [m.rgMbid, m]));
+  const libItems = await prisma.libraryItem.findMany({ where: { artist: artistName, album: { in: albums } } });
+  const haveAlbums = new Set(libItems.map((l) => l.album));
+
+  const releases = visible.map((g) => {
+    const m = monMap.get(g.rgMbid);
+    return {
+      rgMbid: g.rgMbid,
+      album: g.title,
+      primaryType: g.primaryType,
+      secondaryTypes: g.secondaryTypes,
+      firstReleaseDate: g.firstReleaseDate,
+      monitored: m?.monitored ?? false,
+      have: m?.currentQualityClass != null || haveAlbums.has(g.title),
+    };
+  });
+
+  return Response.json({ artistName, followed, releases });
+}