diff --git a/internal/embed-smoke.mjs b/internal/embed-smoke.mjs
index 36e0246b3..93ce5246e 100644
--- a/internal/embed-smoke.mjs
+++ b/internal/embed-smoke.mjs
@@ -91,7 +91,22 @@ for (const t of list) {
     if (verdict.errorCard) r.why = 'ProfileLoader error card shown'
     else if (verdict.nodes < 5) r.why = `shadow DOM nearly empty (${verdict.nodes} nodes)`
     else { r.ok = true; r.why = `${verdict.nodes} nodes${verdict.canvas ? ' + canvas' : ' (no canvas — DOM profile)'}` }
-  } catch (e) { r.why = 'mount timeout / ' + String(e.message || e).slice(0, 100) }
+  } catch (e) {
+    // ★ DO NOT COLLAPSE EVERY REJECTION INTO "mount timeout" — that is a DIAGNOSIS, and it was
+    // the WRONG one. A malformed @element in the manifest made querySelector throw a SyntaxError;
+    // reported as "mount timeout", it accused big-picture (tab-1 of the cap-5 SPA) of being a
+    // broken plugin for as long as this suite has existed. The plugin was fine; the SELECTOR was
+    // invalid. Name what actually happened and let the reader diagnose.
+    const msg = String(e.message || e)
+    if (/SyntaxError|is not a valid selector|failed to execute 'queryselector'/i.test(msg)) {
+      r.why = `INVALID SELECTOR — @element is not a bare tag: ${JSON.stringify(t.element)} ` +
+              '(fix the @element JSDoc in the bundle\'s root .vue; it is copied verbatim into manifest.json)'
+    } else if (/Timeout|exceeded/i.test(msg)) {
+      r.why = 'mount timeout / ' + msg.slice(0, 100)
+    } else {
+      r.why = 'error / ' + msg.slice(0, 100)
+    }
+  }
   if (errors.length && r.ok) r.why += ` · ${errors.length} pageerror(s): ${errors[0]}`
   results.push(r)
   console.log(`  ${r.ok ? '✓' : '✗'} ${t.bundle}/${t.profile} <${t.element}> — ${r.why}`)
diff --git a/plugin-designs/big-picture/big-picture.vue b/plugin-designs/big-picture/big-picture.vue
index 5d5dc4e46..a18cd502d 100644
--- a/plugin-designs/big-picture/big-picture.vue
+++ b/plugin-designs/big-picture/big-picture.vue
@@ -34,7 +34,17 @@
  *
  * @profile     big-picture
  * @bundle      big-picture
- * @element     bp-big-picture (this composite) + bp-research-header + people-groups-grid (nested)
+ * @element     bp-big-picture
+ *
+ * ★ @element MUST BE A BARE TAG — ONE VALID CSS SELECTOR, NOTHING ELSE.
+ * It was previously prose: "bp-big-picture (this composite) + bp-research-header +
+ * people-groups-grid (nested)". generate-tree copies @element VERBATIM into manifest.json, and
+ * consumers feed that value straight to document.querySelector(). The prose threw
+ * "SyntaxError: Failed to execute 'querySelector'", which embed-smoke's catch-all reported as
+ * "mount timeout" — so a DATA defect in this comment masqueraded as a BROKEN PLUGIN, on the one
+ * bundle that is tab-1 of the cap-5 SPA. big-picture mounts fine; only this string was invalid.
+ * Every other bundle in the repo declares a single bare tag; this was the lone outlier.
+ * The nested elements are documented above and in @composes — they do not belong in @element.
  *
  * Becomes tab-1 of the Cat-5 SPA.
  */