diff --git a/src/data.js b/src/data.js
index 34ecf71..04be80a 100644
--- a/src/data.js
+++ b/src/data.js
@@ -2101,7 +2101,10 @@ function loadSessionDetail(sessionId, project) {
           if (role === 'user' || role === 'assistant') {
             const content = extractContent(entry.payload.content);
             if (content && !isSystemMessage(content)) {
-              messages.push({ role: role, content: content.slice(0, 2000), uuid: '' });
+              const msg = { role: role, content: content.slice(0, 2000), uuid: '' };
+              const structured = parseStructuredMessage('codex', role, content);
+              if (structured) msg.structured = structured;
+              messages.push(msg);
             }
           }
           // Codex function_call → attach as tool to last assistant message
@@ -2482,6 +2485,98 @@ function extractContent(raw) {
   return String(raw);
 }
 
+const CODEX_STRUCTURED_MESSAGE_FIELDS = {
+  user_shell_command: [
+    { field: 'command', max_length: 0 },
+    { field: 'result', max_length: 1500 },
+  ],
+  user_action: [
+    { field: 'context', max_length: 200 },
+    { field: 'action', max_length: 0 },
+    { field: 'results', max_length: 1500 },
+  ],
+};
+
+function normalizeStructuredField(value) {
+  return typeof value === 'string' ? value.trim() : '';
+}
+
+function truncateStructuredField(value, maxLength) {
+  if (typeof value !== 'string') return '';
+  if (!maxLength || maxLength < 0 || value.length <= maxLength) return value;
+  return value.slice(0, maxLength);
+}
+
+function parseStructuredWrapper(content) {
+  const trimmed = typeof content === 'string' ? content.trim() : '';
+  if (!trimmed) return null;
+  const match = trimmed.match(/^<([a-z_][a-z0-9_]*)>\s*([\s\S]*?)\s*<\/\1>$/i);
+  if (!match) return null;
+  return { tag: match[1], body: match[2] };
+}
+
+function parseStructuredFields(body, fieldDescriptors) {
+  if (!body || !Array.isArray(fieldDescriptors) || fieldDescriptors.length === 0) return null;
+
+  const fields = {};
+  const allowedFields = new Set(fieldDescriptors.map(function(def) { return def.field; }));
+  const pattern = /<([a-z_][a-z0-9_]*)>([\s\S]*?)<\/\1>/ig;
+  let cursor = 0;
+  let match;
+
+  while ((match = pattern.exec(body))) {
+    if (body.slice(cursor, match.index).trim()) return null;
+
+    const tag = match[1];
+    if (!allowedFields.has(tag) || fields[tag] !== undefined) return null;
+
+    const value = normalizeStructuredField(match[2]);
+    if (!value) return null;
+    fields[tag] = value;
+    cursor = match.index + match[0].length;
+  }
+
+  if (body.slice(cursor).trim()) return null;
+  if (Object.keys(fields).length !== fieldDescriptors.length) return null;
+
+  for (const def of fieldDescriptors) {
+    if (!fields[def.field]) return null;
+  }
+
+  return fields;
+}
+
+function applyStructuredFieldThresholds(fields, fieldDescriptors) {
+  const result = {};
+  for (const def of fieldDescriptors) {
+    result[def.field] = truncateStructuredField(fields[def.field], def.max_length || 0);
+  }
+  return result;
+}
+
+function parseCodexStructuredMessage(content) {
+  const wrapped = parseStructuredWrapper(content);
+  if (!wrapped) return null;
+
+  const fieldDescriptors = CODEX_STRUCTURED_MESSAGE_FIELDS[wrapped.tag];
+  if (!fieldDescriptors) return null;
+
+  const fields = parseStructuredFields(wrapped.body, fieldDescriptors);
+  if (!fields) return null;
+
+  return {
+    agent: 'codex',
+    kind: wrapped.tag,
+    fields: applyStructuredFieldThresholds(fields, fieldDescriptors),
+  };
+}
+
+function parseStructuredMessage(agent, role, content) {
+  if (role !== 'user' || !content) return null;
+  if (agent === 'codex') return parseCodexStructuredMessage(content);
+  return null;
+}
+
 // Extract MCP/Skill tool_use blocks from a Claude assistant message content array.
 // Returns deduplicated array of { type, server, tool } or { type, skill }.
 function extractTools(contentBlocks) {
diff --git a/src/frontend/detail.js b/src/frontend/detail.js
index 0f2ef85..c17abbb 100644
--- a/src/frontend/detail.js
+++ b/src/frontend/detail.js
@@ -184,6 +184,53 @@ function closeDetail() {
   if (overlay) overlay.classList.remove('open');
 }
 
+var structuredMessageRenderers = {
+  'codex:user_shell_command': renderCodexUserShellCommand,
+  'codex:user_action': renderCodexUserAction,
+};
+
+function renderStructuredBlock(text) {
+  return '<pre class="structured-block">' + escHtml(text || '') + '</pre>';
+}
+
+function renderStructuredSection(label, text) {
+  return '<div class="structured-section-label">' + escHtml(label) + '</div>' + renderStructuredBlock(text);
+}
+
+function renderCodexUserShellCommand(fields) {
+  if (!fields || !fields.command || !fields.result) return '';
+  var html = '<div class="msg-content structured-message">';
+  html += '<div class="structured-title">User Shell Command:</div>';
+  html += renderStructuredSection('Command:', fields.command);
+  html += renderStructuredSection('Result:', fields.result);
+  html += '</div>';
+  return html;
+}
+
+function renderCodexUserAction(fields) {
+  if (!fields || !fields.context || !fields.action || !fields.results) return '';
+  var html = '<div class="msg-content structured-message">';
+  html += '<div class="structured-title">User Action:</div>';
+  html += '<div class="structured-context"><span class="structured-context-label">Context:</span> ' + escHtml(fields.context) + '</div>';
+  html += renderStructuredSection('Action:', fields.action);
+  html += renderStructuredSection('Results:', fields.results);
+  html += '</div>';
+  return html;
+}
+
+function renderMessageContent(message) {
+  var structured = message && message.structured;
+  if (structured && structured.agent && structured.kind) {
+    var key = structured.agent + ':' + structured.kind;
+    var renderer = structuredMessageRenderers[key];
+    if (renderer) {
+      var rendered = renderer(structured.fields || {});
+      if (rendered) return rendered;
+    }
+  }
+  return '<div class="msg-content msg-content-plain">' + escHtml((message && message.content) || '') + '</div>';
+}
+
 function renderDetailMessages(container, messages) {
   var sort = localStorage.getItem('codedash-msg-sort') || 'asc';
   var sorted = sort === 'desc' ? messages.slice().reverse() : messages;
@@ -199,7 +246,7 @@ function renderDetailMessages(container, messages) {
     msgsHtml += '<div class="message ' + roleClass + (hasTools ? ' has-tools' : '') + '">';
     msgsHtml += '<div class="msg-inner">';
     msgsHtml += '<div class="msg-role">' + roleLabel + '</div>';
-    msgsHtml += '<div class="msg-content">' + escHtml(m.content) + '</div>';
+    msgsHtml += renderMessageContent(m);
     msgsHtml += '</div>';
     if (hasTools) {
       msgsHtml += '<div class="msg-tools">';
diff --git a/src/frontend/styles.css b/src/frontend/styles.css
index d810a4a..06560f4 100644
--- a/src/frontend/styles.css
+++ b/src/frontend/styles.css
@@ -1542,6 +1542,50 @@ body {
     white-space: pre-wrap;
 }
 
+.msg-content-plain {
+    white-space: pre-wrap;
+}
+
+.structured-message {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+    white-space: normal;
+}
+
+.structured-title,
+.structured-section-label {
+    font-size: 12px;
+    font-weight: 700;
+    color: var(--text-primary);
+}
+
+.structured-context {
+    font-size: 13px;
+    line-height: 1.5;
+    color: var(--text-secondary);
+}
+
+.structured-context-label {
+    font-weight: 700;
+    color: var(--text-primary);
+}
+
+.structured-block {
+    margin: 0;
+    padding: 10px 12px;
+    border-radius: 8px;
+    border: 1px solid var(--border);
+    background: var(--bg-card);
+    color: var(--text-primary);
+    font-family: monospace;
+    font-size: 12px;
+    line-height: 1.5;
+    white-space: pre-wrap;
+    word-break: break-word;
+    overflow-x: auto;
+}
+
 /* ── Commits ────────────────────────────────────────────────── */
 
 .commit-item {