diff --git a/src/web/public/app.js b/src/web/public/app.js
index b23e29ff..37e8f411 100644
--- a/src/web/public/app.js
+++ b/src/web/public/app.js
@@ -827,6 +827,7 @@ class CodemanApp {
         this.closeAllPanels();
         this.closeHelp();
         if (this.attachmentHistoryDrawerOpen) this.closeAttachmentHistory();
+        this.closeSessionManager();
       }
 
       // Option/Alt session navigation uses physical key CODES, not e.key, so macOS
diff --git a/src/web/public/index.html b/src/web/public/index.html
index 8de0fb3f..e55f6074 100644
--- a/src/web/public/index.html
+++ b/src/web/public/index.html
@@ -118,7 +118,7 @@
         </div>
         <button class="btn-icon-header btn-redraw-terminal btn-redraw-terminal--hidden" onclick="app.restoreTerminalSize()" title="Redraw terminal to fit current screen (Ctrl+Shift+R)" aria-label="Redraw terminal"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polyline points="1 4 1 10 7 10"/><polyline points="23 20 23 14 17 14"/><path d="M20.49 9A9 9 0 0 0 5.64 5.64L1 10m22 4l-4.64 4.36A9 9 0 0 1 3.51 15"/></svg></button>
         <button class="btn-icon-header btn-response-viewer-header btn-response-viewer-header--hidden" onclick="app.toggleResponseViewer()" title="View last response" aria-label="View last response"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg></button>
-        <button class="btn-icon-header btn-away-digest" onclick="app.openAwayDigest()" title="Away Digest" aria-label="Open away digest"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M8 6h13"/><path d="M8 12h13"/><path d="M8 18h13"/><path d="M3 6h.01"/><path d="M3 12h.01"/><path d="M3 18h.01"/></svg></button>
+        <button class="btn-icon-header btn-away-digest" onclick="app.openAwayDigest()" title="Away Digest" aria-label="Open away digest"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M8 6h13"/><path d="M8 12h13"/><path d="M8 18h13"/><path d="M3 6h.01"/><path d="M3 12h.01"/><path d="M3 18h.01"/></svg></button> <button class="btn-icon-header btn-session-manager" onclick="app.openSessionManager()" title="Session Manager" aria-label="Open session manager"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polyline points="12 2 2 7 12 12 22 7 12 2"/><polyline points="2 17 12 22 22 17"/><polyline points="2 12 12 17 22 12"/></svg></button>
         <button class="btn-icon-header btn-attachments-history btn-attachments-history--hidden" id="attachmentsHistoryBtn" onclick="app.toggleAttachmentHistory()" title="Attachments" aria-label="Open attachment history" aria-expanded="false">
           <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="m21.44 11.05-9.19 9.19a6 6 0 0 1-8.49-8.49l9.19-9.19a4 4 0 0 1 5.66 5.66l-9.2 9.19a2 2 0 0 1-2.83-2.83l8.49-8.48"/></svg>
           <span class="attachment-history-badge" id="attachmentHistoryBadge" style="display:none;">0</span>
@@ -1956,6 +1956,21 @@
       </div>
     </div>
 
+    <!-- Session Manager Modal -->
+    <div class="modal" id="sessionManagerModal">
+      <div class="modal-backdrop" onclick="app.closeSessionManager()"></div>
+      <div class="modal-content session-manager-modal">
+        <div class="modal-header">
+          <h3>Sessions</h3>
+          <button class="modal-close" onclick="app.closeSessionManager()" aria-label="Close session manager">&times;</button>
+        </div>
+        <div class="modal-body">
+          <input type="search" id="sessionManagerSearch" class="search-input" placeholder="Search sessions by name, prompt, or path&hellip;" autocomplete="off" maxlength="200">
+          <div id="sessionManagerList" class="session-manager-list"></div>
+        </div>
+      </div>
+    </div>
+
     <!-- Token Stats Modal -->
     <div class="modal" id="tokenStatsModal">
       <div class="modal-backdrop" onclick="app.closeTokenStats()"></div>
diff --git a/src/web/public/panels-ui.js b/src/web/public/panels-ui.js
index 26918a95..40353734 100644
--- a/src/web/public/panels-ui.js
+++ b/src/web/public/panels-ui.js
@@ -278,6 +278,100 @@ Object.assign(CodemanApp.prototype, {
     if (modal) modal.classList.remove('active');
   },
 
+  // ═══════════════════════════════════════════════════════════════
+  // Session Manager Modal (COD-121)
+  // Persistent, header-reachable session list (GET /api/sessions/unified)
+  // reachable mid-session, with a server-side search box. Reuses the
+  // unit-2 history item renderer so clicking resumes/switches sessions.
+  // ═══════════════════════════════════════════════════════════════
+
+  async openSessionManager() {
+    const modal = document.getElementById('sessionManagerModal');
+    if (modal) {
+      modal.classList.add('active');
+      // Escape closes the modal even while focus is in the search input. A
+      // modal-scoped listener is robust regardless of the global Escape chain
+      // (which runs other close handlers first and can short-circuit). Wire once.
+      if (!this._sessionManagerEscWired) {
+        this._sessionManagerEscWired = true;
+        modal.addEventListener('keydown', (e) => {
+          if (e.key === 'Escape') {
+            e.preventDefault();
+            e.stopPropagation();
+            this.closeSessionManager();
+          }
+        });
+      }
+    }
+
+    // Ensure cases are loaded so item subtitles can show "#caseName" labels.
+    // Mirror loadHistorySessions(): prefer already-loaded this.cases.
+    if (!Array.isArray(this.cases) || this.cases.length === 0) {
+      try {
+        const r = await fetch('/api/cases');
+        const d = r.ok ? await r.json() : null;
+        this.cases = d?.data || [];
+      } catch {
+        this.cases = this.cases || [];
+      }
+    }
+
+    const search = document.getElementById('sessionManagerSearch');
+    if (search) {
+      // Wire the debounced search input once (lazy — the element exists by
+      // the time the modal is first opened, and mixin methods are bound).
+      if (!this._sessionManagerSearchWired) {
+        this._sessionManagerSearchWired = true;
+        search.addEventListener('input', () => {
+          const value = search.value.trim();
+          this._debouncedCall('sessionManagerSearch', () => this._loadSessionManagerList(value), 200);
+        });
+      }
+      search.value = '';
+      search.focus();
+    }
+    await this._loadSessionManagerList('');
+  },
+
+  closeSessionManager() {
+    const modal = document.getElementById('sessionManagerModal');
+    if (modal) modal.classList.remove('active');
+  },
+
+  async _loadSessionManagerList(q = '') {
+    const list = document.getElementById('sessionManagerList');
+    if (!list) return;
+    try {
+      const url = '/api/sessions/unified?limit=200' + (q ? '&q=' + encodeURIComponent(q) : '');
+      const res = await fetch(url);
+      const data = await res.json();
+      const sessions = data.data?.sessions || [];
+      list.replaceChildren();
+      if (sessions.length === 0) {
+        const empty = document.createElement('p');
+        empty.className = 'empty-message';
+        empty.textContent = q ? 'No sessions match your search' : 'No sessions found';
+        list.appendChild(empty);
+        return;
+      }
+      for (const s of sessions) {
+        const item = this._buildHistoryItem(s, this.cases, { showViewAll: false });
+        // Close the modal when an item is clicked; the underlying
+        // resume/select (registered on the item) still fires because this
+        // is a capture-phase listener that does not stop propagation.
+        item.addEventListener('click', () => this.closeSessionManager(), true);
+        list.appendChild(item);
+      }
+    } catch (err) {
+      console.error('[_loadSessionManagerList]', err);
+      list.replaceChildren();
+      const errLine = document.createElement('p');
+      errLine.className = 'empty-message';
+      errLine.textContent = 'Failed to load sessions';
+      list.appendChild(errLine);
+    }
+  },
+
   setAwayDigestRange(range) {
     this.awayDigestRange = range;
     this._awayDigestLoadedSuccessfully = false;
diff --git a/src/web/public/styles.css b/src/web/public/styles.css
index d05f4d96..6d2c5398 100644
--- a/src/web/public/styles.css
+++ b/src/web/public/styles.css
@@ -5443,6 +5443,34 @@ kbd {
   padding: 1rem;
 }
 
+/* Session Manager modal (COD-121) */
+.session-manager-modal {
+  max-width: 720px;
+  width: min(92vw, 720px);
+  max-height: 70vh;
+  display: flex;
+  flex-direction: column;
+}
+
+.session-manager-modal .modal-body {
+  display: flex;
+  flex-direction: column;
+  gap: 0.6rem;
+  overflow: hidden;
+  padding: 1rem;
+}
+
+#sessionManagerSearch {
+  flex: 0 0 auto;
+}
+
+.session-manager-list {
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+  overflow-y: auto;
+}
+
 .away-digest-ranges {
   display: flex;
   flex-wrap: wrap;