diff --git a/popup.html b/popup.html
index 353ddc8..0d12463 100644
--- a/popup.html
+++ b/popup.html
@@ -139,6 +139,9 @@
         <button id="debug-open" class="link-btn" aria-haspopup="menu" aria-expanded="false">Debug</button>
         <div id="debug-menu" class="menu up" role="menu" hidden>
           <button id="debug-welcome" class="item" role="menuitem">Open welcome page</button>
+          <button id="debug-rescan" class="item" role="menuitem">Re-scan this page</button>
+          <button id="debug-drop-cache" class="item" role="menuitem">Drop cache</button>
+          <p id="debug-note" class="menu-note" role="status" hidden></p>
         </div>
       </div>
     </footer>
diff --git a/src/popup/popup.css b/src/popup/popup.css
index 98d449d..1730edf 100644
--- a/src/popup/popup.css
+++ b/src/popup/popup.css
@@ -696,6 +696,16 @@ actor-typeahead {
   position: relative;
   display: flex;
 }
+/* What the last debug action did, said in the menu that started it: the two
+   that fetch have no other place to report, and the popup's status pills are
+   redrawn from page state rather than written to. */
+.menu-note[hidden] { display: none; }
+.menu-note {
+  margin: 4px 8px 2px;
+  color: var(--muted);
+  font-size: 12px;
+}
+
 /* Nothing sits below the footer for a menu to drop into, so this one rises. */
 .menu.up {
   top: auto;
diff --git a/src/popup/popup.ts b/src/popup/popup.ts
index fcbfa8c..6c40604 100644
--- a/src/popup/popup.ts
+++ b/src/popup/popup.ts
@@ -720,12 +720,30 @@ $('feedback-cancel').addEventListener('click', () => setFeedbackPanel(false))
 
 // --- debug menu (dev channel only) ---
 //
-// Where dev-only tools go. Today it holds one: the welcome page, which Chrome
-// otherwise shows exactly once per install (src/background.ts) and which is
-// therefore impossible to look at again without reinstalling the extension.
+// Where dev-only tools go, all of them reaching something a released build
+// deliberately makes unreachable:
+//
+//   - the welcome page, which Chrome otherwise shows exactly once per install
+//     (src/background.ts) and which is therefore impossible to look at again
+//     without reinstalling the extension;
+//   - a re-scan, which the header's Refresh button also does but which lives
+//     inside the publication section, so it is hidden on exactly the pages a
+//     re-scan is most wanted for: the ones detection found nothing on;
+//   - dropping every cached read, which nothing else does at all. Refresh
+//     bypasses the caches on the path it walks; this empties them, so the
+//     next read of anything — on any tab, from a cold worker — runs the miss
+//     path a user with a warm cache would never see.
 function setDebugMenu(open: boolean) {
   $('debug-menu').hidden = !open
   $('debug-open').setAttribute('aria-expanded', String(open))
+  // A result belongs to the action that produced it, not to the next opening.
+  if (open) debugNote('')
+}
+
+/** What the last debug action did. Cleared whenever the menu opens. */
+function debugNote(text: string) {
+  $('debug-note').textContent = text
+  $('debug-note').hidden = !text
 }
 
 if (isDevChannel()) $('debug-area').hidden = false
@@ -737,6 +755,31 @@ $('debug-open').addEventListener('click', (e) => {
 
 $('debug-welcome').addEventListener('click', () => openUrl(welcomeUrl()))
 
+// Both of the below stop the click reaching the document-level close-all
+// handler: the menu is where the answer is written, so it has to still be
+// open when the answer arrives.
+$('debug-rescan').addEventListener('click', async (e) => {
+  e.stopPropagation()
+  debugNote('Re-scanning…')
+  await loadState(true)
+  debugNote(requestFailed ? 'Re-scan failed; see the console.' : 'Re-scanned.')
+})
+
+// Only drops. Re-scanning from here would refill on the way out, and watching
+// a cold read happen is the reason to empty the caches in the first place —
+// so which read runs next is left to whoever asked.
+$('debug-drop-cache').addEventListener('click', async (e) => {
+  e.stopPropagation()
+  debugNote('Dropping…')
+  try {
+    const { dropped } = await send<{ dropped: number }>({ type: 'drop-caches' })
+    debugNote(`Dropped ${dropped} ${dropped === 1 ? 'entry' : 'entries'}.`)
+  } catch (err) {
+    console.debug('[substandard] drop-caches failed', err)
+    debugNote(err instanceof Error ? err.message : String(err))
+  }
+})
+
 $('feedback-form').addEventListener('submit', async (e) => {
   e.preventDefault()
   const note = $('feedback-note')