diff --git a/TASKS.md b/TASKS.md
index 0900790..f515676 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -2,20 +2,18 @@
 
 ## Current
 
-### `feat/distributed-mcp-session-store`
+### `feat/frontend-xss-hardening`
 
 Status: in_progress
 
 DoD:
-- transport sessions are stored behind a shared store abstraction
-- mcp-server no longer depends directly on process-local session storage implementation
-- in-memory session store remains available for tests and local fallback
-- production mcp-server uses a Postgres-backed transport session store
-- expired transport sessions are evicted on read and no longer leak indefinitely
+- API-provided values are not rendered into `innerHTML` on user-facing admin pages
+- error strings from API responses are rendered through text nodes
+- streaming admin pages use DOM construction instead of HTML string concatenation for dynamic cards
 
 ## Next
 
-- `feat/runtime-rate-limiting-and-backpressure`
+- `feat/distributed-mcp-session-store`
 
 ## Backlog
 
diff --git a/apps/ui/js/async-jobs.js b/apps/ui/js/async-jobs.js
index aa17190..a7adc06 100644
--- a/apps/ui/js/async-jobs.js
+++ b/apps/ui/js/async-jobs.js
@@ -33,8 +33,93 @@ document.addEventListener('DOMContentLoaded', function () {
     return new Date(value).toLocaleString();
   }
 
+  function element(tag, className, text) {
+    var node = document.createElement(tag);
+    if (className) node.className = className;
+    if (text !== undefined && text !== null) node.textContent = text;
+    return node;
+  }
+
   function renderEmpty(title, body) {
-    list.innerHTML = '<div class="empty-state"><div class="empty-state-title">' + title + '</div><div class="empty-state-text">' + body + '</div></div>';
+    list.innerHTML = '';
+    var empty = element('div', 'empty-state');
+    empty.appendChild(element('div', 'empty-state-title', title));
+    empty.appendChild(element('div', 'empty-state-text', body));
+    list.appendChild(empty);
+  }
+
+  function appendMetaItem(parent, label, value) {
+    var item = element('div', 'resource-meta-item');
+    item.appendChild(element('div', 'resource-meta-label', label));
+    item.appendChild(element('div', 'resource-meta-value', value));
+    parent.appendChild(item);
+  }
+
+  function appendDetailBlock(parent, title, value, dataResultFor) {
+    var block = element('div', 'resource-detail-block');
+    block.appendChild(element('div', 'resource-detail-title', title));
+    var pre = element('pre', 'resource-detail-pre', value);
+    if (dataResultFor) pre.setAttribute('data-result-for', dataResultFor);
+    block.appendChild(pre);
+    parent.appendChild(block);
+  }
+
+  function renderJobCard(item) {
+    var open = state.openId === item.id;
+    var card = element('div', 'resource-card');
+    card.setAttribute('data-job-id', item.id);
+
+    var header = element('div', 'resource-card-header');
+    var headerMain = element('div');
+    headerMain.appendChild(element('div', 'resource-card-title', item.id));
+    headerMain.appendChild(element('div', 'resource-card-subtitle', tKey('async_jobs.operation', { operation: item.operation_id })));
+
+    var pillRow = element('div', 'resource-pill-row');
+    pillRow.appendChild(
+      element('span', 'resource-status-pill ' + String(item.status || '').toLowerCase(), tKey('async_jobs.status.' + item.status))
+    );
+    headerMain.appendChild(pillRow);
+    header.appendChild(headerMain);
+
+    var actions = element('div', 'resource-card-actions');
+    if (item.status === 'created' || item.status === 'running') {
+      var cancelButton = element('button', 'btn-secondary', tKey('async_jobs.cancel'));
+      cancelButton.setAttribute('data-action', 'cancel');
+      cancelButton.setAttribute('data-job-id', item.id);
+      actions.appendChild(cancelButton);
+    }
+    var toggleButton = element(
+      'button',
+      'btn-secondary',
+      open ? tKey('async_jobs.hide_details') : tKey('async_jobs.show_details')
+    );
+    toggleButton.setAttribute('data-action', 'toggle');
+    toggleButton.setAttribute('data-job-id', item.id);
+    actions.appendChild(toggleButton);
+    header.appendChild(actions);
+    card.appendChild(header);
+
+    var metaGrid = element('div', 'resource-meta-grid');
+    appendMetaItem(metaGrid, tKey('async_jobs.meta.created'), formatDateTime(item.created_at));
+    appendMetaItem(metaGrid, tKey('async_jobs.meta.updated'), formatDateTime(item.updated_at));
+    appendMetaItem(metaGrid, tKey('async_jobs.meta.finished'), formatDateTime(item.finished_at));
+    appendMetaItem(metaGrid, tKey('async_jobs.meta.expires'), formatDateTime(item.expires_at));
+    card.appendChild(metaGrid);
+
+    if (open) {
+      appendDetailBlock(card, tKey('async_jobs.progress'), formatJson(item.progress));
+      appendDetailBlock(card, tKey('async_jobs.error_preview'), formatJson(item.error));
+      if (
+        item.status === 'completed' ||
+        item.status === 'failed' ||
+        item.status === 'cancelled' ||
+        item.status === 'expired'
+      ) {
+        appendDetailBlock(card, tKey('async_jobs.result'), tKey('async_jobs.result_loading'), item.id);
+      }
+    }
+
+    return card;
   }
 
   function render() {
@@ -55,44 +140,10 @@ document.addEventListener('DOMContentLoaded', function () {
       return;
     }
 
-    list.innerHTML = state.items.map(function(item) {
-      var open = state.openId === item.id;
-      var statusLabel = tKey('async_jobs.status.' + item.status);
-      return [
-        '<div class="resource-card" data-job-id="' + item.id + '">',
-        '  <div class="resource-card-header">',
-        '    <div>',
-        '      <div class="resource-card-title">' + item.id + '</div>',
-        '      <div class="resource-card-subtitle">' + tKey('async_jobs.operation', { operation: item.operation_id }) + '</div>',
-        '      <div class="resource-pill-row">',
-        '        <span class="resource-status-pill ' + String(item.status || '').toLowerCase() + '">' + statusLabel + '</span>',
-        '      </div>',
-        '    </div>',
-        '    <div class="resource-card-actions">',
-        item.status === 'created' || item.status === 'running'
-          ? '      <button class="btn-secondary" data-action="cancel" data-job-id="' + item.id + '">' + tKey('async_jobs.cancel') + '</button>'
-          : '',
-        '      <button class="btn-secondary" data-action="toggle" data-job-id="' + item.id + '">' + (open ? tKey('async_jobs.hide_details') : tKey('async_jobs.show_details')) + '</button>',
-        '    </div>',
-        '  </div>',
-        '  <div class="resource-meta-grid">',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('async_jobs.meta.created') + '</div><div class="resource-meta-value">' + formatDateTime(item.created_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('async_jobs.meta.updated') + '</div><div class="resource-meta-value">' + formatDateTime(item.updated_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('async_jobs.meta.finished') + '</div><div class="resource-meta-value">' + formatDateTime(item.finished_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('async_jobs.meta.expires') + '</div><div class="resource-meta-value">' + formatDateTime(item.expires_at) + '</div></div>',
-        '  </div>',
-        open
-          ? '  <div class="resource-detail-block"><div class="resource-detail-title">' + tKey('async_jobs.progress') + '</div><pre class="resource-detail-pre">' + formatJson(item.progress) + '</pre></div>'
-          : '',
-        open
-          ? '  <div class="resource-detail-block"><div class="resource-detail-title">' + tKey('async_jobs.error_preview') + '</div><pre class="resource-detail-pre">' + formatJson(item.error) + '</pre></div>'
-          : '',
-        open && (item.status === 'completed' || item.status === 'failed' || item.status === 'cancelled' || item.status === 'expired')
-          ? '  <div class="resource-detail-block"><div class="resource-detail-title">' + tKey('async_jobs.result') + '</div><pre class="resource-detail-pre" data-result-for="' + item.id + '">' + tKey('async_jobs.result_loading') + '</pre></div>'
-          : '',
-        '</div>'
-      ].join('');
-    }).join('');
+    list.innerHTML = '';
+    state.items.forEach(function(item) {
+      list.appendChild(renderJobCard(item));
+    });
 
     list.querySelectorAll('[data-action="toggle"]').forEach(function(button) {
       button.addEventListener('click', function () {
diff --git a/apps/ui/js/stream-sessions.js b/apps/ui/js/stream-sessions.js
index 57e7b0d..aeae084 100644
--- a/apps/ui/js/stream-sessions.js
+++ b/apps/ui/js/stream-sessions.js
@@ -34,8 +34,83 @@ document.addEventListener('DOMContentLoaded', function () {
     return new Date(value).toLocaleString();
   }
 
+  function element(tag, className, text) {
+    var node = document.createElement(tag);
+    if (className) node.className = className;
+    if (text !== undefined && text !== null) node.textContent = text;
+    return node;
+  }
+
   function renderEmpty(title, body) {
-    list.innerHTML = '<div class="empty-state"><div class="empty-state-title">' + title + '</div><div class="empty-state-text">' + body + '</div></div>';
+    list.innerHTML = '';
+    var empty = element('div', 'empty-state');
+    empty.appendChild(element('div', 'empty-state-title', title));
+    empty.appendChild(element('div', 'empty-state-text', body));
+    list.appendChild(empty);
+  }
+
+  function appendMetaItem(parent, label, value) {
+    var item = element('div', 'resource-meta-item');
+    item.appendChild(element('div', 'resource-meta-label', label));
+    item.appendChild(element('div', 'resource-meta-value', value));
+    parent.appendChild(item);
+  }
+
+  function appendDetailBlock(parent, title, value) {
+    var block = element('div', 'resource-detail-block');
+    block.appendChild(element('div', 'resource-detail-title', title));
+    block.appendChild(element('pre', 'resource-detail-pre', formatJson(value)));
+    parent.appendChild(block);
+  }
+
+  function renderSessionCard(item) {
+    var open = state.openId === item.id;
+    var card = element('div', 'resource-card');
+    card.setAttribute('data-session-id', item.id);
+
+    var header = element('div', 'resource-card-header');
+    var headerMain = element('div');
+    headerMain.appendChild(element('div', 'resource-card-title', item.id));
+    headerMain.appendChild(element('div', 'resource-card-subtitle', tKey('stream_sessions.operation', { operation: item.operation_id })));
+
+    var pillRow = element('div', 'resource-pill-row');
+    var statusPill = element('span', 'resource-status-pill ' + String(item.status || '').toLowerCase(), tKey('stream_sessions.status.' + item.status));
+    pillRow.appendChild(statusPill);
+    pillRow.appendChild(element('span', 'resource-status-pill', item.mode));
+    pillRow.appendChild(element('span', 'resource-status-pill', item.protocol));
+    headerMain.appendChild(pillRow);
+    header.appendChild(headerMain);
+
+    var actions = element('div', 'resource-card-actions');
+    if (item.status === 'created' || item.status === 'running') {
+      var stopButton = element('button', 'btn-secondary', tKey('stream_sessions.stop'));
+      stopButton.setAttribute('data-action', 'stop');
+      stopButton.setAttribute('data-session-id', item.id);
+      actions.appendChild(stopButton);
+    }
+    var toggleButton = element(
+      'button',
+      'btn-secondary',
+      open ? tKey('stream_sessions.hide_details') : tKey('stream_sessions.show_details')
+    );
+    toggleButton.setAttribute('data-action', 'toggle');
+    toggleButton.setAttribute('data-session-id', item.id);
+    actions.appendChild(toggleButton);
+    header.appendChild(actions);
+    card.appendChild(header);
+
+    var metaGrid = element('div', 'resource-meta-grid');
+    appendMetaItem(metaGrid, tKey('stream_sessions.meta.created'), formatDateTime(item.created_at));
+    appendMetaItem(metaGrid, tKey('stream_sessions.meta.last_poll'), formatDateTime(item.last_poll_at));
+    appendMetaItem(metaGrid, tKey('stream_sessions.meta.expires'), formatDateTime(item.expires_at));
+    appendMetaItem(metaGrid, tKey('stream_sessions.meta.agent'), item.agent_id || '—');
+    card.appendChild(metaGrid);
+
+    if (open) {
+      appendDetailBlock(card, tKey('stream_sessions.cursor'), item.cursor);
+    }
+
+    return card;
   }
 
   function render() {
@@ -56,40 +131,10 @@ document.addEventListener('DOMContentLoaded', function () {
       return;
     }
 
-    list.innerHTML = state.items.map(function(item) {
-      var open = state.openId === item.id;
-      var statusLabel = tKey('stream_sessions.status.' + item.status);
-      return [
-        '<div class="resource-card" data-session-id="' + item.id + '">',
-        '  <div class="resource-card-header">',
-        '    <div>',
-        '      <div class="resource-card-title">' + item.id + '</div>',
-        '      <div class="resource-card-subtitle">' + tKey('stream_sessions.operation', { operation: item.operation_id }) + '</div>',
-        '      <div class="resource-pill-row">',
-        '        <span class="resource-status-pill ' + String(item.status || '').toLowerCase() + '">' + statusLabel + '</span>',
-        '        <span class="resource-status-pill">' + item.mode + '</span>',
-        '        <span class="resource-status-pill">' + item.protocol + '</span>',
-        '      </div>',
-        '    </div>',
-        '    <div class="resource-card-actions">',
-        item.status === 'created' || item.status === 'running'
-          ? '      <button class="btn-secondary" data-action="stop" data-session-id="' + item.id + '">' + tKey('stream_sessions.stop') + '</button>'
-          : '',
-        '      <button class="btn-secondary" data-action="toggle" data-session-id="' + item.id + '">' + (open ? tKey('stream_sessions.hide_details') : tKey('stream_sessions.show_details')) + '</button>',
-        '    </div>',
-        '  </div>',
-        '  <div class="resource-meta-grid">',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('stream_sessions.meta.created') + '</div><div class="resource-meta-value">' + formatDateTime(item.created_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('stream_sessions.meta.last_poll') + '</div><div class="resource-meta-value">' + formatDateTime(item.last_poll_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('stream_sessions.meta.expires') + '</div><div class="resource-meta-value">' + formatDateTime(item.expires_at) + '</div></div>',
-        '    <div class="resource-meta-item"><div class="resource-meta-label">' + tKey('stream_sessions.meta.agent') + '</div><div class="resource-meta-value">' + (item.agent_id || '—') + '</div></div>',
-        '  </div>',
-        open
-          ? '  <div class="resource-detail-block"><div class="resource-detail-title">' + tKey('stream_sessions.cursor') + '</div><pre class="resource-detail-pre">' + formatJson(item.cursor) + '</pre></div>'
-          : '',
-        '</div>'
-      ].join('');
-    }).join('');
+    list.innerHTML = '';
+    state.items.forEach(function(item) {
+      list.appendChild(renderSessionCard(item));
+    });
 
     list.querySelectorAll('[data-action="toggle"]').forEach(function(button) {
       button.addEventListener('click', function () {