diff --git a/plugins/thread-hover-cards/app.tsx b/plugins/thread-hover-cards/app.tsx
index 4327513..bcb622d 100644
--- a/plugins/thread-hover-cards/app.tsx
+++ b/plugins/thread-hover-cards/app.tsx
@@ -821,6 +821,49 @@ function renderError(card: HTMLElement): void {
   );
 }
 
+type HoverCardRenderState = "complete" | "error" | "loading" | "summary";
+
+function setHoverCardRenderState(
+  card: HTMLElement,
+  state: HoverCardRenderState,
+): void {
+  card.dataset.bbHoverCardRenderState = state;
+  if (state === "loading" || state === "summary") {
+    card.setAttribute("aria-busy", "true");
+  } else {
+    card.removeAttribute("aria-busy");
+  }
+}
+
+function nextPaint(): Promise<void> {
+  return new Promise((resolve) => requestAnimationFrame(() => resolve()));
+}
+
+async function waitForCardAssets(card: HTMLElement): Promise<void> {
+  const fonts = document.fonts?.ready;
+  const images = Array.from(card.querySelectorAll("img"));
+  await Promise.all([
+    fonts ?? Promise.resolve(),
+    ...images.map((image) => {
+      if (image.complete) return image.decode?.().catch(() => undefined);
+      return new Promise<void>((resolve) => {
+        image.addEventListener("load", () => resolve(), { once: true });
+        image.addEventListener("error", () => resolve(), { once: true });
+      });
+    }),
+  ]);
+}
+
+async function markHoverCardComplete(
+  card: HTMLElement,
+  isCurrent: () => boolean,
+): Promise<void> {
+  await waitForCardAssets(card);
+  await nextPaint();
+  await nextPaint();
+  if (isCurrent()) setHoverCardRenderState(card, "complete");
+}
+
 function renderSummary(card: HTMLElement, summary: ThreadSummary): void {
   const header = element("div", "bb-thread-hover-card__header");
   const provider = element("div", "bb-thread-hover-card__provider");
@@ -1497,7 +1540,7 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
     threadId: string,
     generation: number,
     hoverCard: HTMLDivElement,
-  ): void {
+  ): Promise<void> {
     const cached = cache.get(threadId);
     if (
       cached?.timingFetchedAt !== null &&
@@ -1511,10 +1554,10 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
         outcome: "ok",
         threadId,
       });
-      return;
+      return Promise.resolve();
     }
 
-    void requestTiming(threadId)
+    return requestTiming(threadId)
       .then((timing) => {
         const current = cache.get(threadId);
         if (!current) return;
@@ -1530,9 +1573,11 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
           ) {
             timingRetriedForSummary.set(threadId, summaryStartedAt);
             timingRetryScheduled.add(threadId);
-            queueMicrotask(() => {
-              timingRetryScheduled.delete(threadId);
-              refreshTiming(threadId, generation, hoverCard);
+            return new Promise<void>((resolve) => {
+              queueMicrotask(() => {
+                timingRetryScheduled.delete(threadId);
+                void refreshTiming(threadId, generation, hoverCard).then(resolve);
+              });
             });
           }
           return;
@@ -1578,9 +1623,9 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
     threadId: string,
     generation: number,
     hoverCard: HTMLDivElement,
-  ): void {
+  ): Promise<void> {
     const cached = cache.get(threadId);
-    if (!cached?.summary.repository.isGitRepository) return;
+    if (!cached?.summary.repository.isGitRepository) return Promise.resolve();
     const repositoryKey = pullRequestRepositoryIdentity(
       cached.summary.repository,
     );
@@ -1595,10 +1640,10 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
         outcome: "ok",
         threadId,
       });
-      return;
+      return Promise.resolve();
     }
 
-    void requestPullRequest(threadId, repositoryKey)
+    return requestPullRequest(threadId, repositoryKey)
       .then(({ pullRequest, repository }) => {
         const current = cache.get(threadId);
         if (
@@ -1641,6 +1686,27 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
       .catch(() => undefined);
   }
 
+  function finishRendering(
+    threadId: string,
+    generation: number,
+    hoverCard: HTMLDivElement,
+  ): void {
+    setHoverCardRenderState(hoverCard, "summary");
+    void Promise.all([
+      refreshTiming(threadId, generation, hoverCard),
+      refreshPullRequest(threadId, generation, hoverCard),
+    ]).then(() =>
+      markHoverCardComplete(
+        hoverCard,
+        () =>
+          !disposed &&
+          generation === requestGeneration &&
+          activeThreadId === threadId &&
+          resolveActiveTrigger() !== null,
+      ),
+    );
+  }
+
   function resolveActiveTrigger(): HTMLAnchorElement | null {
     if (!activeThreadId) return null;
     if (
@@ -1723,6 +1789,7 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
     const generation = requestGeneration;
     abortSupersededSummaryRequests(threadId);
     const hoverCard = ensureCard();
+    setHoverCardRenderState(hoverCard, "loading");
     hoverCard.hidden = false;
     hoverCard.classList.remove("is-visible");
     void hoverCard.offsetWidth;
@@ -1756,8 +1823,7 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
         threadId,
       });
       if (cacheIsFresh) {
-        refreshTiming(threadId, generation, hoverCard);
-        refreshPullRequest(threadId, generation, hoverCard);
+        finishRendering(threadId, generation, hoverCard);
         return;
       }
     }
@@ -1799,8 +1865,7 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
           (replacementPullRequestLink ?? resolveActiveTrigger())?.focus();
         }
         requestAnimationFrame(positionCard);
-        refreshTiming(threadId, generation, hoverCard);
-        refreshPullRequest(threadId, generation, hoverCard);
+        finishRendering(threadId, generation, hoverCard);
       })
       .catch((error) => {
         if (
@@ -1811,6 +1876,7 @@ function installHoverCards({ onOpen }: ThreadHoverCardOptions): HoverCardControl
           resolveActiveTrigger()
         ) {
           renderError(hoverCard);
+          setHoverCardRenderState(hoverCard, "error");
           recordTiming({
             cache: "miss",
             durationMs: elapsedMs(requestedAt),
@@ -2226,16 +2292,24 @@ function installSectionHoverCards({
     generation += 1;
     const requestGeneration = generation;
     const hoverCard = ensureCard();
+    setHoverCardRenderState(hoverCard, "loading");
     hoverCard.hidden = false;
     hoverCard.classList.remove("is-visible");
     void hoverCard.offsetWidth;
     hoverCard.classList.add("is-visible");
     const key = keyOf(target);
     const cached = cache.get(key);
-    if (cached) renderSectionSummary(hoverCard, cached.summary);
-    else renderLoading(hoverCard, "section");
+    if (cached) {
+      renderSectionSummary(hoverCard, cached.summary);
+      setHoverCardRenderState(hoverCard, "summary");
+    } else renderLoading(hoverCard, "section");
     requestAnimationFrame(position);
     if (cached && Date.now() - cached.fetchedAt < SECTION_SUMMARY_CACHE_TTL_MS) {
+      void markHoverCardComplete(
+        hoverCard,
+        () =>
+          !disposed && requestGeneration === generation && active !== null,
+      );
       return;
     }
 
@@ -2248,11 +2322,20 @@ function installSectionHoverCards({
         if (disposed || requestGeneration !== generation) return;
         renderSectionSummary(hoverCard, summary);
         requestAnimationFrame(position);
+        setHoverCardRenderState(hoverCard, "summary");
+        void markHoverCardComplete(
+          hoverCard,
+          () =>
+            !disposed &&
+            requestGeneration === generation &&
+            active !== null,
+        );
       })
       .catch((error) => {
         if (disposed || requestGeneration !== generation || cached) return;
         if (isAbortError(error)) return;
         renderError(hoverCard);
+        setHoverCardRenderState(hoverCard, "error");
         requestAnimationFrame(position);
       });
   }
diff --git a/plugins/thread-hover-cards/dist/app.js b/plugins/thread-hover-cards/dist/app.js
index ff0c961..e121b8d 100644
--- a/plugins/thread-hover-cards/dist/app.js
+++ b/plugins/thread-hover-cards/dist/app.js
@@ -1778,6 +1778,37 @@ function renderError(card) {
     element("p", "bb-thread-hover-card__loading", "Summary unavailable")
   );
 }
+function setHoverCardRenderState(card, state) {
+  card.dataset.bbHoverCardRenderState = state;
+  if (state === "loading" || state === "summary") {
+    card.setAttribute("aria-busy", "true");
+  } else {
+    card.removeAttribute("aria-busy");
+  }
+}
+function nextPaint() {
+  return new Promise((resolve) => requestAnimationFrame(() => resolve()));
+}
+async function waitForCardAssets(card) {
+  const fonts = document.fonts?.ready;
+  const images = Array.from(card.querySelectorAll("img"));
+  await Promise.all([
+    fonts ?? Promise.resolve(),
+    ...images.map((image) => {
+      if (image.complete) return image.decode?.().catch(() => void 0);
+      return new Promise((resolve) => {
+        image.addEventListener("load", () => resolve(), { once: true });
+        image.addEventListener("error", () => resolve(), { once: true });
+      });
+    })
+  ]);
+}
+async function markHoverCardComplete(card, isCurrent) {
+  await waitForCardAssets(card);
+  await nextPaint();
+  await nextPaint();
+  if (isCurrent()) setHoverCardRenderState(card, "complete");
+}
 function renderSummary(card, summary) {
   const header = element("div", "bb-thread-hover-card__header");
   const provider = element("div", "bb-thread-hover-card__provider");
@@ -2339,9 +2370,9 @@ function installHoverCards({ onOpen }) {
         outcome: "ok",
         threadId
       });
-      return;
+      return Promise.resolve();
     }
-    void requestTiming(threadId).then((timing) => {
+    return requestTiming(threadId).then((timing) => {
       const current = cache.get(threadId);
       if (!current) return;
       const summaryStartedAt = current.summary.diagnostics.startedAt;
@@ -2349,9 +2380,11 @@ function installHoverCards({ onOpen }) {
         if (!disposed && generation === requestGeneration && activeThreadId === threadId && resolveActiveTrigger() && timingRetriedForSummary.get(threadId) !== summaryStartedAt && !timingRetryScheduled.has(threadId)) {
           timingRetriedForSummary.set(threadId, summaryStartedAt);
           timingRetryScheduled.add(threadId);
-          queueMicrotask(() => {
-            timingRetryScheduled.delete(threadId);
-            refreshTiming(threadId, generation, hoverCard);
+          return new Promise((resolve) => {
+            queueMicrotask(() => {
+              timingRetryScheduled.delete(threadId);
+              void refreshTiming(threadId, generation, hoverCard).then(resolve);
+            });
           });
         }
         return;
@@ -2384,7 +2417,7 @@ function installHoverCards({ onOpen }) {
   }
   function refreshPullRequest(threadId, generation, hoverCard) {
     const cached = cache.get(threadId);
-    if (!cached?.summary.repository.isGitRepository) return;
+    if (!cached?.summary.repository.isGitRepository) return Promise.resolve();
     const repositoryKey = pullRequestRepositoryIdentity(
       cached.summary.repository
     );
@@ -2396,9 +2429,9 @@ function installHoverCards({ onOpen }) {
         outcome: "ok",
         threadId
       });
-      return;
+      return Promise.resolve();
     }
-    void requestPullRequest(threadId, repositoryKey).then(({ pullRequest, repository }) => {
+    return requestPullRequest(threadId, repositoryKey).then(({ pullRequest, repository }) => {
       const current = cache.get(threadId);
       if (!current || pullRequestRepositoryIdentity(repository) !== repositoryKey || pullRequestRepositoryIdentity(current.summary.repository) !== repositoryKey) {
         return;
@@ -2424,6 +2457,18 @@ function installHoverCards({ onOpen }) {
       requestAnimationFrame(positionCard);
     }).catch(() => void 0);
   }
+  function finishRendering(threadId, generation, hoverCard) {
+    setHoverCardRenderState(hoverCard, "summary");
+    void Promise.all([
+      refreshTiming(threadId, generation, hoverCard),
+      refreshPullRequest(threadId, generation, hoverCard)
+    ]).then(
+      () => markHoverCardComplete(
+        hoverCard,
+        () => !disposed && generation === requestGeneration && activeThreadId === threadId && resolveActiveTrigger() !== null
+      )
+    );
+  }
   function resolveActiveTrigger() {
     if (!activeThreadId) return null;
     if (activeTrigger?.isConnected && threadIdFor(activeTrigger) === activeThreadId) {
@@ -2475,6 +2520,7 @@ function installHoverCards({ onOpen }) {
     const generation = requestGeneration;
     abortSupersededSummaryRequests(threadId);
     const hoverCard = ensureCard();
+    setHoverCardRenderState(hoverCard, "loading");
     hoverCard.hidden = false;
     hoverCard.classList.remove("is-visible");
     void hoverCard.offsetWidth;
@@ -2504,8 +2550,7 @@ function installHoverCards({ onOpen }) {
         threadId
       });
       if (cacheIsFresh) {
-        refreshTiming(threadId, generation, hoverCard);
-        refreshPullRequest(threadId, generation, hoverCard);
+        finishRendering(threadId, generation, hoverCard);
         return;
       }
     }
@@ -2537,11 +2582,11 @@ function installHoverCards({ onOpen }) {
         (replacementPullRequestLink ?? resolveActiveTrigger())?.focus();
       }
       requestAnimationFrame(positionCard);
-      refreshTiming(threadId, generation, hoverCard);
-      refreshPullRequest(threadId, generation, hoverCard);
+      finishRendering(threadId, generation, hoverCard);
     }).catch((error) => {
       if (!cached && !disposed && generation === requestGeneration && activeThreadId === threadId && resolveActiveTrigger()) {
         renderError(hoverCard);
+        setHoverCardRenderState(hoverCard, "error");
         recordTiming({
           cache: "miss",
           durationMs: elapsedMs(requestedAt),
@@ -2864,16 +2909,23 @@ function installSectionHoverCards({
     generation += 1;
     const requestGeneration = generation;
     const hoverCard = ensureCard();
+    setHoverCardRenderState(hoverCard, "loading");
     hoverCard.hidden = false;
     hoverCard.classList.remove("is-visible");
     void hoverCard.offsetWidth;
     hoverCard.classList.add("is-visible");
     const key = keyOf(target);
     const cached = cache.get(key);
-    if (cached) renderSectionSummary(hoverCard, cached.summary);
-    else renderLoading(hoverCard, "section");
+    if (cached) {
+      renderSectionSummary(hoverCard, cached.summary);
+      setHoverCardRenderState(hoverCard, "summary");
+    } else renderLoading(hoverCard, "section");
     requestAnimationFrame(position);
     if (cached && Date.now() - cached.fetchedAt < SECTION_SUMMARY_CACHE_TTL_MS) {
+      void markHoverCardComplete(
+        hoverCard,
+        () => !disposed && requestGeneration === generation && active !== null
+      );
       return;
     }
     void requestSummary(target).then((summary) => {
@@ -2884,10 +2936,16 @@ function installSectionHoverCards({
       if (disposed || requestGeneration !== generation) return;
       renderSectionSummary(hoverCard, summary);
       requestAnimationFrame(position);
+      setHoverCardRenderState(hoverCard, "summary");
+      void markHoverCardComplete(
+        hoverCard,
+        () => !disposed && requestGeneration === generation && active !== null
+      );
     }).catch((error) => {
       if (disposed || requestGeneration !== generation || cached) return;
       if (isAbortError(error)) return;
       renderError(hoverCard);
+      setHoverCardRenderState(hoverCard, "error");
       requestAnimationFrame(position);
     });
   }
diff --git a/plugins/thread-hover-cards/test/app.test.mjs b/plugins/thread-hover-cards/test/app.test.mjs
index 256bdfc..ebc76dc 100644
--- a/plugins/thread-hover-cards/test/app.test.mjs
+++ b/plugins/thread-hover-cards/test/app.test.mjs
@@ -594,6 +594,8 @@ trigger.dispatchEvent(pointerOver);
 const card = window.document.getElementById("bb-thread-hover-card");
 assert.ok(card, "opens the hover card in the pointer event turn");
 assert.equal(card.hidden, false);
+assert.equal(card.dataset.bbHoverCardRenderState, "loading");
+assert.equal(card.getAttribute("aria-busy"), "true");
 assert.deepEqual(
   requestBodies,
   [{ threadId: "thr_1" }],
@@ -610,6 +612,8 @@ assert.match(card.textContent, /Loading thread summary/);
 await new Promise((resolve) => setTimeout(resolve, 20));
 
 assert.equal(card.hidden, false);
+assert.equal(card.dataset.bbHoverCardRenderState, "complete");
+assert.equal(card.hasAttribute("aria-busy"), false);
 assert.equal(card.dataset.bbPlugin, "thread-hover-cards");
 assert.equal(card.hasAttribute("data-bb-portaled-overlay"), true);
 assert.equal(trigger.getAttribute("aria-describedby"), "bb-thread-hover-card");
@@ -1424,12 +1428,20 @@ testNow += 2_100;
 delayNextTimingFor.add("thr_summary_before_timing");
 await closeAndOpenThread("thr_summary_before_timing", 10);
 assert.ok(delayedTimingResponses.has("thr_summary_before_timing"));
+assert.equal(
+  reloadedCard.dataset.bbHoverCardRenderState,
+  "summary",
+  "does not advertise screenshot readiness while timing is still pending",
+);
+assert.equal(reloadedCard.getAttribute("aria-busy"), "true");
 assert.ok(
   reloadedCard.querySelector(".bb-thread-hover-card__runtime"),
   "keeps hydrated runtime while summary resolves before timing",
 );
 delayedTimingResponses.get("thr_summary_before_timing")?.();
 await new Promise((resolve) => setTimeout(resolve, 20));
+assert.equal(reloadedCard.dataset.bbHoverCardRenderState, "complete");
+assert.equal(reloadedCard.hasAttribute("aria-busy"), false);
 assert.ok(reloadedCard.querySelector(".bb-thread-hover-card__runtime"));
 assert.equal(
   timingRequestBodies.filter(
@@ -1526,6 +1538,18 @@ assert.doesNotMatch(
   "ignores a late PR response for the previous branch",
 );
 
+delayNextPullRequestFor.add("thr_slow_pr");
+await closeAndOpenThread("thr_slow_pr", 20);
+assert.ok(delayedPullRequestResponses.has("thr_slow_pr"));
+assert.equal(
+  reloadedCard.dataset.bbHoverCardRenderState,
+  "summary",
+  "does not advertise screenshot readiness while PR content is still pending",
+);
+delayedPullRequestResponses.get("thr_slow_pr")?.();
+await new Promise((resolve) => setTimeout(resolve, 20));
+assert.equal(reloadedCard.dataset.bbHoverCardRenderState, "complete");
+
 for (const expected of [
   {
     threadId: "thr_blocked_pr",
@@ -1699,6 +1723,7 @@ await new Promise((resolve) => setTimeout(resolve, 20));
 const sectionCard = window.document.getElementById("bb-section-hover-card");
 assert.ok(sectionCard, "opens a card from the section header row");
 assert.equal(sectionCard.hidden, false);
+assert.equal(sectionCard.dataset.bbHoverCardRenderState, "complete");
 assert.equal(
   designHeader.toggle.getAttribute("aria-describedby"),
   "bb-section-hover-card",
@@ -1769,6 +1794,20 @@ sectionGroup.append(delayedAHeader.row, delayedBHeader.row);
 hoverOver(delayedBHeader.title);
 await new Promise((resolve) => setTimeout(resolve, 20));
 assert.match(sectionCard.textContent, /2 threads/);
+
+delayNextSectionFor.add("Delayed A");
+hoverOver(delayedAHeader.title);
+await new Promise((resolve) => setTimeout(resolve, 0));
+assert.equal(sectionCard.dataset.bbHoverCardRenderState, "loading");
+assert.equal(sectionCard.getAttribute("aria-busy"), "true");
+delayedSectionResponses.get("Delayed A")?.();
+await new Promise((resolve) => setTimeout(resolve, 20));
+assert.equal(sectionCard.dataset.bbHoverCardRenderState, "complete");
+assert.equal(sectionCard.hasAttribute("aria-busy"), false);
+
+hoverOver(delayedBHeader.title);
+await new Promise((resolve) => setTimeout(resolve, 20));
+testNow += 4_100;
 delayNextSectionFor.add("Delayed A");
 hoverOver(delayedAHeader.title);
 await new Promise((resolve) => setTimeout(resolve, 0));