diff --git a/backend/src/services/providerCollectionsService.ts b/backend/src/services/providerCollectionsService.ts
index 10281b5..ce60a49 100644
--- a/backend/src/services/providerCollectionsService.ts
+++ b/backend/src/services/providerCollectionsService.ts
@@ -30,6 +30,8 @@ import {
   fetchThingiverseLikesSummary,
   listThingiverseUserCollections,
   resolveThingiverseUser,
+  ThingiverseAuthError,
+  ThingiverseRateLimitError,
 } from "./thingiverseApi";
 
 export const BROWSABLE_PROVIDERS = ["makerworld", "printables", "thingiverse"] as const;
@@ -93,7 +95,8 @@ export async function setProviderAccount(
     });
     if (!user) await deletePrintablesListings(userId);
   } else if (provider === "thingiverse") {
-    const user = value ? await resolveThingiverseUser(value, await requireThingiverseToken()) : null;
+    const token = value ? await requireThingiverseToken() : null;
+    const user = token ? await providerCall(() => resolveThingiverseUser(value!, token)) : null;
     if (value && !user) throw new HttpError(404, `Thingiverse has no user "${value}"`);
     await prisma.user.update({ where: { id: userId }, data: { thingiverseUsername: user?.username ?? null } });
   } else {
@@ -127,6 +130,8 @@ async function providerCall<T>(call: () => Promise<T>): Promise<T> {
     if (err instanceof MakerworldAuthError) {
       throw new HttpError(400, "MakerWorld didn't accept your cookie. Update it in Configuration > Providers.");
     }
+    if (err instanceof ThingiverseRateLimitError) throw new HttpError(429, err.message);
+    if (err instanceof ThingiverseAuthError) throw new HttpError(400, err.message);
     throw err;
   }
 }
@@ -185,10 +190,12 @@ export async function listProviderCollections(
     if (!user?.thingiverseUsername) throw new HttpError(409, "Tell Thingport your Thingiverse username first");
     const username = user.thingiverseUsername;
     // Thingiverse shows anyone's likes, so they sync like a collection; a failed count costs only them.
-    const [likes, collections] = await Promise.all([
-      thingiverseLikesCard(username, token).catch(() => null),
-      listThingiverseUserCollections(username, token),
-    ]);
+    const [likes, collections] = await providerCall(() =>
+      Promise.all([
+        thingiverseLikesCard(username, token).catch(() => null),
+        listThingiverseUserCollections(username, token),
+      ]),
+    );
     cards = [...(likes ? [likes] : []), ...collections];
   }
   return withSyncs(userId, provider, cards);
@@ -200,7 +207,8 @@ export async function lookupProviderCollection(userId: string, url: string): Pro
   if (!source) throw new HttpError(400, "That isn't a MakerWorld, Printables or Thingiverse collection link");
   let card: ProviderCollectionCard | null;
   if (source.likesOf && source.provider === "thingiverse") {
-    card = await thingiverseLikesCard(source.likesOf, await requireThingiverseToken());
+    const token = await requireThingiverseToken();
+    card = await providerCall(() => thingiverseLikesCard(source.likesOf!, token));
   } else if (source.likesOf) {
     // Printables shows likes to their owner only, so only the user's own, as Grab read them.
     const likes = await pushedLikes(userId);
@@ -220,7 +228,8 @@ export async function lookupProviderCollection(userId: string, url: string): Pro
       (await pushedPrintablesCards(userId)).collections?.find((pushed) => pushed.id === source.externalId) ??
       null;
   } else {
-    card = await fetchThingiverseCollectionCard(source.externalId, await requireThingiverseToken());
+    const token = await requireThingiverseToken();
+    card = await providerCall(() => fetchThingiverseCollectionCard(source.externalId, token));
   }
   if (!card) throw new HttpError(404, "That collection can't be found. It may be private or deleted.");
   return (await withSyncs(userId, source.provider, [card]))[0];
diff --git a/backend/src/services/thingiverseApi.ts b/backend/src/services/thingiverseApi.ts
index 1edaa3e..dec17ca 100644
--- a/backend/src/services/thingiverseApi.ts
+++ b/backend/src/services/thingiverseApi.ts
@@ -8,6 +8,7 @@ import {
   looksLikeCloudflareBlock,
   shouldProxyHost,
 } from "./flaresolverr";
+import { getFlaresolverrUrl } from "./settingsService";
 
 // The official API needs an app Access Token (not a session cookie). It's still behind Cloudflare
 // and returns a sticky 429 challenge after a few rapid requests, hence ThingiverseRateLimitError
@@ -31,12 +32,19 @@ export class ThingiverseAuthError extends Error {
   }
 }
 
-/** Cloudflare's 429 challenge, distinct from a 404 or rejected token: the fix is to wait. */
+const FLARESOLVERR_HINTS = {
+  missing: " Setting up FlareSolverr in Admin Settings > Connections gets past it.",
+  failed:
+    " FlareSolverr couldn't get past it either: it may be down or unreachable. Check it in Admin Settings > Connections.",
+};
+
+/** Cloudflare's 429 challenge, distinct from a 404 or rejected token: the fix is to wait, or a working FlareSolverr. */
 export class ThingiverseRateLimitError extends Error {
-  constructor() {
+  constructor(flaresolverr?: keyof typeof FLARESOLVERR_HINTS) {
     super(
       "Thingiverse blocked this request with a rate-limit challenge (Cloudflare). This usually " +
-        "clears after a while -- wait, then retry the same import.",
+        "clears after a while -- wait, then try again." +
+        (flaresolverr ? FLARESOLVERR_HINTS[flaresolverr] : ""),
     );
     this.name = "ThingiverseRateLimitError";
   }
@@ -126,6 +134,10 @@ async function fetchThingiverseApi(
       data = null;
     }
   }
+  // An unsolved challenge is a 403 too; it says nothing about the token.
+  if (!viaBrowser && (res.status === 429 || res.headers.get("cf-mitigated") === "challenge")) {
+    throw new ThingiverseRateLimitError((await getFlaresolverrUrl()) ? "failed" : "missing");
+  }
   if (res.status === 429) throw new ThingiverseRateLimitError();
   if (res.status === 401 || res.status === 403) throw new ThingiverseAuthError();
   return { ok: res.ok, status: res.status, data };
diff --git a/backend/tests/providerCollections.test.ts b/backend/tests/providerCollections.test.ts
index 907ee41..9342c04 100644
--- a/backend/tests/providerCollections.test.ts
+++ b/backend/tests/providerCollections.test.ts
@@ -96,6 +96,13 @@ beforeAll(async () => {
     // Thingiverse's API as it answers for a user with two likes and one collection.
     const thingiverse = url.match(/^https:\/\/api\.thingiverse\.com(\/[^?]*)/);
     if (thingiverse) {
+      if (url.includes("access_token=rejected-token")) return json({}, 401);
+      if (url.includes("access_token=challenged-token")) {
+        return new Response("<title>Just a moment...</title>", {
+          status: 403,
+          headers: { "cf-mitigated": "challenge" },
+        });
+      }
       const path = thingiverse[1];
       if (path === `/users/${THINGIVERSE_USER}`) return json({ name: THINGIVERSE_USER, like_count: 2 });
       if (path === `/users/${THINGIVERSE_USER}/likes`) {
@@ -229,6 +236,22 @@ describe("Thingiverse likes in the Browse tab", () => {
       thumbnails: ["https://cdn.thingiverse.com/hook.jpg", "https://cdn.thingiverse.com/clip.jpg"],
     });
   });
+
+  it("says the instance's token was rejected, rather than failing", async () => {
+    await setThingiverseAccessToken("rejected-token");
+    const list = await request(app).get("/api/provider-collections").query({ provider: "thingiverse" }).set(auth());
+    expect(list.status).toBe(400);
+    expect(list.body.detail).toMatch(/Access Token .* was rejected/);
+    await setThingiverseAccessToken("test-token");
+  });
+
+  it("tells a Cloudflare challenge from a rejected token", async () => {
+    await setThingiverseAccessToken("challenged-token");
+    const list = await request(app).get("/api/provider-collections").query({ provider: "thingiverse" }).set(auth());
+    expect(list.status).toBe(429);
+    expect(list.body.detail).toMatch(/Cloudflare.*Setting up FlareSolverr/);
+    await setThingiverseAccessToken("test-token");
+  });
 });
 
 describe("turning sync on from the app", () => {
diff --git a/frontend/src/api/admin.ts b/frontend/src/api/admin.ts
index f66e643..9cefb22 100644
--- a/frontend/src/api/admin.ts
+++ b/frontend/src/api/admin.ts
@@ -35,7 +35,9 @@ export type LogAction =
   | "collection_item_added"
   | "collection_item_removed"
   | "collection_sync_enabled"
-  | "collection_sync_disabled";
+  | "collection_sync_disabled"
+  | "ai_categorization_run"
+  | "ai_description_run";
 
 export type LogEntry = {
   id: string;
diff --git a/frontend/src/components/Layout/AppLayout.tsx b/frontend/src/components/Layout/AppLayout.tsx
index e8efa8e..17f10d6 100644
--- a/frontend/src/components/Layout/AppLayout.tsx
+++ b/frontend/src/components/Layout/AppLayout.tsx
@@ -199,8 +199,9 @@ function AppLayoutShell({
             <PageHeaderContext.Provider value={setPageHeader}>{children}</PageHeaderContext.Provider>
           </Box>
         </Box>
-        {/* Both can run at once, so they stack here rather than each pinning itself to the bottom. */}
-        <Box sx={{ position: "fixed", left: 0, right: 0, bottom: 0, zIndex: (theme) => theme.zIndex.snackbar }}>
+        {/* Both can run at once, so they stack here rather than each pinning itself to the bottom. Under
+            dialogs and their backdrop, like the top bar. */}
+        <Box sx={{ position: "fixed", left: 0, right: 0, bottom: 0, zIndex: (theme) => theme.zIndex.appBar }}>
           <AiRunProgressBar kind="categorization" />
           <AiRunProgressBar kind="descriptions" />
           <ImportProgressBar />
diff --git a/frontend/src/i18n/locales/en.json b/frontend/src/i18n/locales/en.json
index ecbcf51..2828f04 100644
--- a/frontend/src/i18n/locales/en.json
+++ b/frontend/src/i18n/locales/en.json
@@ -927,10 +927,14 @@
           "collection_sync_enabled": "Collection sync turned on",
           "collection_sync_disabled": "Collection sync turned off",
           "authors_linked": "Linked missing authors",
-          "descriptions_refetched": "Refetched model descriptions"
+          "descriptions_refetched": "Refetched model descriptions",
+          "ai_categorization_run": "AI categorization run",
+          "ai_description_run": "AI description improvement run"
         },
         "authorsLinked": "{{count}} model(s) linked",
-        "descriptionsRefetched": "{{email}} — {{updated}} of {{total}} description(s) changed"
+        "descriptionsRefetched": "{{email}} — {{updated}} of {{total}} description(s) changed",
+        "aiRunSummary": "{{done}} of {{total}} checked — {{suggested}} suggested, {{applied}} applied, {{failed}} failed",
+        "aiRunStopped": "(stopped)"
       },
       "rendering": {
         "heading": "Rendering",
diff --git a/frontend/src/i18n/locales/lt.json b/frontend/src/i18n/locales/lt.json
index 69b9be5..b3162d3 100644
--- a/frontend/src/i18n/locales/lt.json
+++ b/frontend/src/i18n/locales/lt.json
@@ -935,10 +935,14 @@
           "collection_sync_enabled": "Įjungtas kolekcijos sinchronizavimas",
           "collection_sync_disabled": "Išjungtas kolekcijos sinchronizavimas",
           "authors_linked": "Susieti trūkstami autoriai",
-          "descriptions_refetched": "Iš naujo gauti modelių aprašymai"
+          "descriptions_refetched": "Iš naujo gauti modelių aprašymai",
+          "ai_categorization_run": "AI kategorizavimo paleidimas",
+          "ai_description_run": "AI aprašymų tobulinimo paleidimas"
         },
         "authorsLinked": "Susieta modelių: {{count}}",
-        "descriptionsRefetched": "{{email}} — pakeista aprašymų: {{updated}} iš {{total}}"
+        "descriptionsRefetched": "{{email}} — pakeista aprašymų: {{updated}} iš {{total}}",
+        "aiRunSummary": "Patikrinta {{done}} iš {{total}} — pasiūlyta {{suggested}}, pritaikyta {{applied}}, nepavyko {{failed}}",
+        "aiRunStopped": "(sustabdyta)"
       },
       "rendering": {
         "heading": "Atvaizdavimas",
diff --git a/frontend/src/pages/AiPage/AiDescriptionsPanel.tsx b/frontend/src/pages/AiPage/AiDescriptionsPanel.tsx
index 55b4653..8e37a32 100644
--- a/frontend/src/pages/AiPage/AiDescriptionsPanel.tsx
+++ b/frontend/src/pages/AiPage/AiDescriptionsPanel.tsx
@@ -50,7 +50,7 @@ export default function AiDescriptionsPanel({ onUnauthorized, onRunStarted }: Pr
   const { t } = useTranslation(["app", "common"]);
   const showToast = useToast();
   const confirm = useConfirm();
-  const { running, startRun } = useAiDescriptionRun();
+  const { run, running, startRun } = useAiDescriptionRun();
   const [suggestions, setSuggestions] = useState<{ total: number; items: AiDescriptionSuggestion[] } | null>(null);
   const [applied, setApplied] = useState<{ total: number; items: AiDescriptionApplied[] } | null>(null);
   const [selected, setSelected] = useState<string[]>([]);
@@ -72,14 +72,16 @@ export default function AiDescriptionsPanel({ onUnauthorized, onRunStarted }: Pr
     ]);
     setSuggestions(pending);
     setApplied(done);
-    setSelected([]);
+    // Only what's still listed stays ticked, so a run adding suggestions doesn't undo a selection.
+    setSelected((ids) => ids.filter((id) => pending.items.some((item) => item.id === id)));
   }, []);
 
-  // Again whenever a run stops, since a run adds suggestions.
+  // On opening, as a run adds suggestions or applies rewrites, and again once it stops.
+  const progress = running ? `${run?.suggested ?? 0}/${run?.applied ?? 0}` : "idle";
   useEffect(() => {
-    if (running) return;
     void load().catch(fail);
-  }, [running, load, fail]);
+    // oxlint-disable-next-line react/exhaustive-effect-dependencies
+  }, [progress, load, fail]);
 
   const act = async (work: () => Promise<unknown>, done: string) => {
     setBusy(true);
diff --git a/frontend/src/pages/LogsPage/index.tsx b/frontend/src/pages/LogsPage/index.tsx
index d6043c2..2bb8e74 100644
--- a/frontend/src/pages/LogsPage/index.tsx
+++ b/frontend/src/pages/LogsPage/index.tsx
@@ -50,6 +50,8 @@ const ACTION_COLORS: Record<LogAction, ActionColor> = {
   collection_item_removed: "default",
   collection_sync_enabled: "info",
   collection_sync_disabled: "default",
+  ai_categorization_run: "info",
+  ai_description_run: "info",
 };
 
 function isoDateOnly(d: Date): string {
@@ -137,6 +139,18 @@ export default function LogsPage({ onUnauthorized }: Props) {
         const failed = typeof d.failed === "number" ? d.failed : 0;
         return t("adminSettings.logs.importSummary", { label, imported, failed });
       }
+      case "ai_categorization_run":
+      case "ai_description_run": {
+        const count = (key: string) => (typeof d[key] === "number" ? d[key] : 0);
+        const summary = t("adminSettings.logs.aiRunSummary", {
+          done: count("done"),
+          total: count("total"),
+          suggested: count("suggested"),
+          applied: count("applied"),
+          failed: count("failed"),
+        });
+        return d.cancelled === true ? `${summary} ${t("adminSettings.logs.aiRunStopped")}` : summary;
+      }
       default:
         return "";
     }
diff --git a/frontend/src/pages/ModelsPage/AiCategorizationPanel.tsx b/frontend/src/pages/ModelsPage/AiCategorizationPanel.tsx
index b547a83..f26cefd 100644
--- a/frontend/src/pages/ModelsPage/AiCategorizationPanel.tsx
+++ b/frontend/src/pages/ModelsPage/AiCategorizationPanel.tsx
@@ -64,7 +64,7 @@ export default function AiCategorizationPanel({
   const [selected, setSelected] = useState<string[]>([]);
   const [busy, setBusy] = useState(false);
   const [suggestionsLoading, setSuggestionsLoading] = useState(true);
-  const { running, startRun } = useAiRun();
+  const { run, running, startRun } = useAiRun();
 
   const loadSuggestions = async (offset = 0, append = false) => {
     const result = await aiCategorizationApi.suggestions(50, offset);
@@ -73,9 +73,9 @@ export default function AiCategorizationPanel({
     if (!append) setSelected([]);
   };
 
-  // Reloaded whenever a run stops, since a run adds suggestions.
+  // On opening, as a run adds suggestions, and again once it stops.
+  const progress = running ? (run?.suggested ?? 0) : -1;
   useEffect(() => {
-    if (running) return;
     let active = true;
     setSuggestionsLoading(true);
     void aiCategorizationApi
@@ -84,7 +84,8 @@ export default function AiCategorizationPanel({
         if (!active) return;
         setItems(result.items);
         setTotal(result.total);
-        setSelected([]);
+        // Only what's still listed stays ticked, so a run adding suggestions doesn't undo a selection.
+        setSelected((ids) => ids.filter((id) => result.items.some((item) => item.id === id)));
       })
       .catch((err: unknown) => {
         if (err instanceof UnauthorizedError) onUnauthorized?.();
@@ -96,11 +97,11 @@ export default function AiCategorizationPanel({
     return () => {
       active = false;
     };
-  }, [running, onUnauthorized, showToast]);
+    // oxlint-disable-next-line react/exhaustive-effect-dependencies
+  }, [progress, onUnauthorized, showToast]);
 
   // Counts on opening, and again after a run, which moves models between the groups.
   useEffect(() => {
-    if (running) return;
     let active = true;
     void aiCategorizationApi
       .runState()
@@ -116,6 +117,7 @@ export default function AiCategorizationPanel({
     return () => {
       active = false;
     };
+    // oxlint-disable-next-line react/exhaustive-effect-dependencies
   }, [running, onUnauthorized, showToast]);
 
   const start = async () => {