diff --git a/gateway/internal/handler/me.go b/gateway/internal/handler/me.go
index 06c5de1..ad740c3 100644
--- a/gateway/internal/handler/me.go
+++ b/gateway/internal/handler/me.go
@@ -153,6 +153,18 @@ func MeSendMail(w http.ResponseWriter, r *http.Request) {
 			repo.AgentModeEnforcement(r.Context(), to.Name))
 	}
 
+	// 续谈已有会话时，人也可以显式改档位。人是权限的源头，
+	// 可以任改三档——与 Agent 不同，人没有「只能同档或更严」的约束。
+	if !created && req.PermissionMode != "" {
+		mode := models.NormalizePermissionMode(req.PermissionMode)
+		if _, err := repo.SetSessionPermissionMode(r.Context(), sessionID, mode); err != nil {
+			Error(w, http.StatusInternalServerError, "Failed to update permission mode")
+			return
+		}
+		_ = repo.SetSessionEnforcement(r.Context(), sessionID,
+			repo.AgentModeEnforcement(r.Context(), to.Name))
+	}
+
 	// 人类侧不产生改名提议（人直接有改名按钮，用不着向自己提议），
 	// 但仍然剥掉标记：粘贴进正文时它会被渲染成一行可见的转义文本。
 	_, body := extractRenameProposal(req.Body)
diff --git a/web/src/components/ComposePage.tsx b/web/src/components/ComposePage.tsx
index baf927b..0dc7295 100644
--- a/web/src/components/ComposePage.tsx
+++ b/web/src/components/ComposePage.tsx
@@ -30,7 +30,7 @@ export default function ComposePage() {
   // 而不是事后到管理员页面去调某个 Agent 的全局配额。
   const [maxRounds, setMaxRounds] = useState('');
   // 权限档位（仅新建会话时生效）：plan / workspace / full。
-  const [permissionMode, setPermissionMode] = useState('');
+  const [permissionMode, setPermissionMode] = useState('workspace');
   // 收件 Agent 的默认预算；null = 还没查到（未注册的收件人也是 null）
   const [agentDefault, setAgentDefault] = useState<number | null>(null);
   const [attachments, setAttachments] = useState<PendingAttachment[]>([]);
@@ -111,7 +111,7 @@ export default function ComposePage() {
         ...(isNewSession && maxRounds.trim() !== ''
           ? { max_rounds: Number(maxRounds.trim()) }
           : {}),
-        ...(isNewSession && permissionMode ? { permission_mode: permissionMode } : {}),
+        ...(permissionMode ? { permission_mode: permissionMode } : {}),
       });
       const where = res.session_alias
         ? `会话别名 ${res.session_alias}`
@@ -191,31 +191,29 @@ export default function ComposePage() {
           </Field>
         )}
 
-        {isNewSession && (
-          <Field label="权限档位" hint="Agent 在这类任务里被允许动手的程度；只在新建会话时生效">
-            <div className="flex items-center gap-2">
-              {[
-                { value: 'plan', label: '只读', desc: '不许写/改/执行' },
-                { value: 'workspace', label: '目录内', desc: '越界问人' },
-                { value: 'full', label: '全权', desc: '自动放行' },
-              ].map(o => (
-                <button
-                  key={o.value}
-                  type="button"
-                  onClick={() => setPermissionMode(o.value)}
-                  title={o.desc}
-                  className={`px-2.5 py-1.5 rounded-md border text-xs font-medium transition-colors ${
-                    permissionMode === o.value
-                      ? 'border-blue-500 bg-blue-50 text-blue-700'
-                      : 'border-gray-300 bg-white text-gray-600 hover:bg-gray-50'
-                  }`}
-                >
-                  {o.label}
-                </button>
-              ))}
-            </div>
-          </Field>
-        )}
+        <Field label="权限档位" hint={isNewSession ? "Agent 在这类任务里被允许动手的程度" : "改了即刻生效（该会话的档位会更新）"}>
+          <div className="flex items-center gap-2">
+            {[
+              { value: 'plan', label: '只读', desc: '不许写/改/执行' },
+              { value: 'workspace', label: '目录内', desc: '越界问人' },
+              { value: 'full', label: '全权', desc: '自动放行' },
+            ].map(o => (
+              <button
+                key={o.value}
+                type="button"
+                onClick={() => setPermissionMode(o.value)}
+                title={o.desc}
+                className={`px-2.5 py-1.5 rounded-md border text-xs font-medium transition-colors ${
+                  permissionMode === o.value
+                    ? 'border-blue-500 bg-blue-50 text-blue-700'
+                    : 'border-gray-300 bg-white text-gray-600 hover:bg-gray-50'
+                }`}
+              >
+                {o.label}
+              </button>
+            ))}
+          </div>
+        </Field>
 
         {isNewSession && (
           <Field label="往返预算" hint="留空 = 用该 Agent 的默认值；之后可在对话页随时调整">