@@ -687,23 +687,32 @@ function sessionList() {
 
 // Push the current list to whichever surfaces are open — the /sessions modal (in the chat webview) and the
 // Sessions sidebar. Called after any lifecycle edit so both stay live.
-function refreshSessions() {
-	const entries = sessionList();
-	try { post({ type: 'sessions', entries, open: false }); } catch (e) { /* chat webview may be closed */ }
-	try { if (sessionsWebview) { sessionsWebview.postMessage({ type: 'sessions', entries }); } } catch (e) { /* sidebar may be closed */ }
-}
-
-// A card action from either surface. resume reopens the session; done/rename/delete are append-only edits
-// (§4.9): Done archives (reversible, never deletes), Delete soft-trashes, Rename retitles. All refresh both
-// surfaces. Best-effort — a History action must never throw into the UI.
+// Post a message to whichever session surfaces are open — the /sessions modal (chat webview) and the
+// Sessions sidebar. Both guarded (either may be closed).
+function postSessions(msg) {
+	try { post(msg); } catch (e) { /* chat webview may be closed */ }
+	try { if (sessionsWebview) { sessionsWebview.postMessage(msg); } } catch (e) { /* sidebar may be closed */ }
+}
+function refreshSessions() { postSessions({ type: 'sessions', entries: sessionList(), open: false }); }
+
+// A card action from either surface. resume reopens the session; done/delete/rename/pin are append-only edits
+// (§4.9): Done archives (reversible, never deletes), Delete soft-trashes, Rename retitles, Pin toggles.
+// Done/Delete offer an Undo (restore) so an accidental click is recoverable. Best-effort — a History action
+// must never throw into the UI.
 async function handleSessionAction(action, id) {
 	const m = sessionsManager();
 	if (!m || !id) { return; }
 	dbg('sessions.action', { action, id });
 	try {
 		if (action === 'resume') { await resumeSession(id); return; }
-		if (action === 'done') { m.archive(id); refreshSessions(); return; }
-		if (action === 'delete') { m.trash(id); refreshSessions(); return; }
+		if (action === 'done' || action === 'delete') {
+			const title = (m.list().find((e) => e.id === id) || {}).title || 'this session';
+			if (action === 'done') { m.archive(id); } else { m.trash(id); }
+			refreshSessions();
+			postSessions({ type: 'sessionUndo', action, id, title });   // offer to undo — the card just vanished
+			return;
+		}
+		if (action === 'restore') { m.restore(id); refreshSessions(); return; }
 		if (action === 'pin') { const cur = (m.list().find((e) => e.id === id) || {}).pinned; m.setPinned(id, !cur); refreshSessions(); return; }
 		if (action === 'rename') {
 			const cur = (m.list().find((e) => e.id === id) || {}).title || '';
 
@@ -1079,6 +1079,12 @@
   .sesspanel .sessbar { display: flex; align-items: center; gap: 9px; padding: 12px 14px 10px; border-bottom: 1px solid var(--cc-line); }
   .sesspanel .sesstitle { font-weight: 600; font-size: 14px; }
   .sesspanel .sesslist { flex: 1 1 auto; overflow-y: auto; padding: 2px 12px 14px; }
+  /* Undo toast pinned at the panel foot after Done/Delete (an accidental click is recoverable). */
+  .sesspanel .sessundo { flex: 0 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 10px; margin: 0 12px 12px; padding: 8px 12px; background: var(--cc-surface); border: 1px solid var(--cc-line); border-radius: 8px; font-size: 12.5px; color: var(--cc-text2); }
+  .sesspanel .sessundo[hidden] { display: none; }
+  .sesspanel .sessundo .ut { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+  .sesspanel .sessundo .ub { flex: 0 0 auto; background: transparent; border: none; color: var(--cc-accent); font: inherit; font-size: 12.5px; font-weight: 600; cursor: pointer; padding: 2px 4px; border-radius: 4px; }
+  .sesspanel .sessundo .ub:hover { text-decoration: underline; }
   .sesspanel .sessbucket { font-family: var(--vscode-editor-font-family, ui-monospace, monospace); font-size: 10px; letter-spacing: .1em; text-transform: uppercase; color: var(--cc-text3); margin: 12px 4px 7px; }
   .sesspanel .sessempty { padding: 44px 18px; text-align: center; color: var(--cc-text3); font-size: 13px; line-height: 1.6; }
   .sesscard { position: relative; background: var(--cc-bg); border: 1px solid var(--cc-line); border-radius: 7px; padding: 9px 11px; margin-bottom: 7px; cursor: pointer; transition: border-color .12s, transform .12s, box-shadow .12s; }
@@ -1231,6 +1237,7 @@
       <button class="ovclose" id="sessClose" title="Close" aria-label="Close">&#10005;</button>
       <div class="sessbar"><span class="sesstitle">Sessions</span></div>
       <div class="sesslist" id="sessList"></div>
+      <div class="sessundo" id="sessUndo" hidden></div>
     </div>
   </div>
 
@@ -3372,6 +3379,15 @@
     renderSessions(); ov.style.display = 'flex';
   }
   function closeSessions(){ const ov = document.getElementById('sessOverlay'); if (ov) { ov.style.display = 'none'; } }
+  // The Undo toast for Done/Delete — a quick, recoverable safety net. Auto-hides after a few seconds.
+  let sessUndoTimer = null;
+  function showUndo(m){
+    const el = document.getElementById('sessUndo'); if (!el) { return; }
+    const verb = m.action === 'delete' ? 'Deleted' : 'Archived';
+    el.innerHTML = '<span class="ut">' + verb + ' “' + esc(m.title || 'session') + '”</span><button class="ub" data-id="' + escAttr(m.id || '') + '">Undo</button>';
+    el.hidden = false;
+    clearTimeout(sessUndoTimer); sessUndoTimer = setTimeout(function(){ el.hidden = true; }, 7000);
+  }
   // Replay a resumed session into the chat: a compact "Resumed" banner (+ the honest summary note, if the
   // transcript was too big to carry verbatim) followed by the readable conversation — user prompts and the
   // assistant's prose, tool plumbing dropped. The host has already reset the log and restored the model's
@@ -3402,6 +3418,12 @@
       vscode.postMessage({ type: 'sessionAction', action: action, id: id });
       if (action === 'resume') { closeSessions(); }
     }); }
+    const undo = document.getElementById('sessUndo');
+    if (undo) { undo.addEventListener('click', (e) => {
+      const b = e.target.closest && e.target.closest('.ub'); if (!b) { return; }
+      vscode.postMessage({ type: 'sessionAction', action: 'restore', id: b.getAttribute('data-id') });
+      undo.hidden = true; clearTimeout(sessUndoTimer);
+    }); }
     document.addEventListener('keydown', (e) => { const o = document.getElementById('sessOverlay'); if (e.key === 'Escape' && o && o.style.display !== 'none'){ e.preventDefault(); closeSessions(); } });
   })();
 
@@ -3460,6 +3482,7 @@
     else if (m.type === 'mcpList'){ renderMcpList(m.mcp || {}); }
     else if (m.type === 'sessions'){ sessData = Array.isArray(m.entries) ? m.entries : []; if (m.open === false) { renderSessions(); } else { openSessions(); } }
     else if (m.type === 'sessionResumed'){ resumeTranscript(m); }
+    else if (m.type === 'sessionUndo'){ showUndo(m); }
     else if (m.type === 'verifyRun'){ addVerifyRun(m); }
     else if (m.type === 'verifyOutput'){ verifyOutputAppend(m); }
     else if (m.type === 'verifyDone'){ verifyDoneFinish(m); }
 
@@ -18,6 +18,12 @@
   .sessview { display: flex; flex-direction: column; height: 100vh; }
   .sessnew { margin: 2px 10px 8px; padding: 7px 10px; background: var(--cc-bg); border: 1px solid var(--cc-line); border-radius: 6px; color: var(--cc-text); font: inherit; font-size: 12.5px; cursor: pointer; text-align: center; }
   .sessnew:hover { border-color: var(--cc-accent); }
+  /* Undo toast pinned at the foot after Done/Delete (an accidental click is recoverable). */
+  .sessundo { flex: 0 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 10px; margin: 0 10px 10px; padding: 8px 11px; background: var(--cc-bg); border: 1px solid var(--cc-line); border-radius: 8px; font-size: 12.5px; color: var(--cc-text2); }
+  .sessundo[hidden] { display: none; }
+  .sessundo .ut { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+  .sessundo .ub { flex: 0 0 auto; background: transparent; border: none; color: var(--cc-accent); font: inherit; font-size: 12.5px; font-weight: 600; cursor: pointer; padding: 2px 4px; border-radius: 4px; }
+  .sessundo .ub:hover { text-decoration: underline; }
   .sesslist { flex: 1 1 auto; overflow-y: auto; padding: 0 10px 12px; }
   .sessbucket { display: flex; justify-content: space-between; align-items: baseline; font-family: var(--vscode-editor-font-family, ui-monospace, monospace); font-size: 10px; letter-spacing: .1em; text-transform: uppercase; color: var(--cc-text3); margin: 12px 4px 7px; }
   .sessbucket .cnt { letter-spacing: 0; }
@@ -52,6 +58,7 @@
   <div class="sessview">
     <button id="svNew" class="sessnew" type="button">New Session</button>
     <div class="sesslist" id="svList"></div>
+    <div class="sessundo" id="svUndo" hidden></div>
   </div>
 <script nonce="__NONCE__">
   const vscode = acquireVsCodeApi();
@@ -147,7 +154,21 @@
     const id = card.getAttribute('data-id'); const btn = e.target.closest('[data-act]');
     vscode.postMessage({ type: 'sessionAction', action: btn ? btn.getAttribute('data-act') : 'resume', id: id });
   });
-  window.addEventListener('message', (ev) => { const m = ev.data; if (m && m.type === 'sessions'){ sessData = Array.isArray(m.entries) ? m.entries : []; renderSessions(); } });
+  // The Undo toast for Done/Delete — a quick, recoverable safety net. Auto-hides after a few seconds.
+  let sessUndoTimer = null;
+  function showUndo(m){
+    const el = document.getElementById('svUndo'); if (!el) { return; }
+    const verb = m.action === 'delete' ? 'Deleted' : 'Archived';
+    el.innerHTML = '<span class="ut">' + verb + ' “' + esc(m.title || 'session') + '”</span><button class="ub" data-id="' + escAttr(m.id || '') + '">Undo</button>';
+    el.hidden = false;
+    clearTimeout(sessUndoTimer); sessUndoTimer = setTimeout(function(){ el.hidden = true; }, 7000);
+  }
+  document.getElementById('svUndo').addEventListener('click', (e) => {
+    const b = e.target.closest && e.target.closest('.ub'); if (!b) { return; }
+    vscode.postMessage({ type: 'sessionAction', action: 'restore', id: b.getAttribute('data-id') });
+    document.getElementById('svUndo').hidden = true; clearTimeout(sessUndoTimer);
+  });
+  window.addEventListener('message', (ev) => { const m = ev.data; if (m && m.type === 'sessions'){ sessData = Array.isArray(m.entries) ? m.entries : []; renderSessions(); } else if (m && m.type === 'sessionUndo'){ showUndo(m); } });
   renderSessions();
   vscode.postMessage({ type: 'listSessions' });
 </script>
 
@@ -119,6 +119,8 @@ function createSessions(opts) {
 	function archive(id) { return appendTo(id, events.labelEvent({ lifecycle: 'archived' }, iso())); }
 	/** Soft delete — moves to the `trashed` lifecycle (reversible, append-only; the file is left on disk). */
 	function trash(id) { return appendTo(id, events.labelEvent({ lifecycle: 'trashed' }, iso())); }
+	/** Bring an archived/trashed session back into the active list — the Undo behind Done/Delete. */
+	function restore(id) { return appendTo(id, events.labelEvent({ lifecycle: 'active' }, iso())); }
 	function setPinned(id, on) { return appendTo(id, events.labelEvent({ pinned: !!on }, iso())); }
 	function rename(id, title) {
 		if (title == null || !String(title).trim()) { return false; }
@@ -152,7 +154,7 @@ function createSessions(opts) {
 
 	function liveId() { return live ? live.id : null; }
 
-	return { ensure, recordTurn, seal, resume, archive, trash, setPinned, rename, autoArchiveStale, list, liveId };
+	return { ensure, recordTurn, seal, resume, archive, trash, restore, setPinned, rename, autoArchiveStale, list, liveId };
 }
 
 module.exports = { createSessions };
@@ -176,6 +176,20 @@ test('MANAGER: archive / rename / trash are append-only edits that update the in
 	assert.strictEqual(m.list().find((e) => e.id === id).lifecycle, 'trashed', 'the latest label event wins');
 });
 
+test('MANAGER: restore reverses Done/Delete (the Undo behind them)', () => {
+	const root = freshRoot(), slug = store.projectSlug('/pu');
+	const m = createSessions({ root, slug, projectPath: '/pu' });
+	m.recordTurn([{ role: 'user', content: 'x' }], 'm');
+	const id = m.liveId();
+	m.archive(id);
+	assert.strictEqual(m.list().find((e) => e.id === id).lifecycle, 'archived');
+	m.restore(id);
+	assert.strictEqual(m.list().find((e) => e.id === id).lifecycle, 'active', 'restore brings an archived session back');
+	m.trash(id);
+	m.restore(id);
+	assert.strictEqual(m.list().find((e) => e.id === id).lifecycle, 'active', 'and a trashed one too');
+});
+
 test('MANAGER: autoArchiveStale fades stale, non-pinned sessions and exempts pinned + recent', () => {
 	const root = freshRoot(), slug = store.projectSlug('/aa');
 	const DAY = 86400000;
 
@@ -145,6 +145,16 @@ test('HOUSEKEEPING: a Pin toggle on the card, and a 30-day auto-archive sweep on
 	assert.ok(/sessActBtn\('pin'/.test(html) && /sessActBtn\('pin'/.test(view), 'both surfaces render a Pin action');
 });
 
+test('UNDO: Done/Delete offer a recoverable Undo (restore) on both surfaces', () => {
+	assert.match(ext, /type: 'sessionUndo'/, 'the host offers an undo after Done/Delete');
+	assert.match(ext, /action === 'restore'\) \{ m\.restore\(id\)/, 'and handles restore (reverses the lifecycle change)');
+	for (const [name, src, uid] of [['modal', html, 'sessUndo'], ['sidebar', view, 'svUndo']]) {
+		assert.match(src, new RegExp('id="' + uid + '"'), name + ': has an undo toast element');
+		assert.match(src, /m\.type === 'sessionUndo'/, name + ': handles the sessionUndo message');
+		assert.match(src, /action: 'restore'/, name + ': the Undo button posts a restore');
+	}
+});
+
 test('VIEW: the sidebar view and the modal share the EXACT same render block (no drift)', () => {
 	const grab = (s) => s.slice(s.indexOf('// [SESSIONS-PURE-START]'), s.indexOf('// [SESSIONS-PURE-END]'));
 	assert.ok(grab(view).length > 500, 'the view carries the pure block');