diff --git a/frontend-web/src/components/workspace/messages/message-token-usage.tsx b/frontend-web/src/components/workspace/messages/message-token-usage.tsx
index f45b2ef0..21cf508b 100644
--- a/frontend-web/src/components/workspace/messages/message-token-usage.tsx
+++ b/frontend-web/src/components/workspace/messages/message-token-usage.tsx
@@ -31,6 +31,44 @@ export function formatDuration(ms: number): string {
   return `${mins}m ${secs}s`;
 }
 
+/**
+ * 速度条颜色含义图例 —— 生成结束后常驻在速度条下方一行，向用户解释进度条
+ * 颜色代表的「模型生成延迟」状态。进度条本身仍是 5 档(极快/流畅/一般/偏慢/
+ * 缓慢)的连续配色;这里把它归并成用户视角的 3 类延迟 + 「无响应」来说明:
+ *   绿(#16a34a，极快/流畅) → 延迟正常
+ *   黄(#eab308，一般)       → 延迟微长
+ *   红(#ef4444，偏慢/缓慢)  → 延迟长，可能失败
+ *   灰(#9ca3af)            → 无响应(无进度条/0 tok/s)，任务失败，请重试
+ */
+const SPEED_LEGEND: { color: string; label: string }[] = [
+  { color: "#16a34a", label: "延迟正常" },
+  { color: "#eab308", label: "延迟微长" },
+  { color: "#ef4444", label: "延迟长，可能失败" },
+  { color: "#9ca3af", label: "无响应，任务失败，请重试" },
+];
+
+export function SpeedLegend({ className }: { className?: string }) {
+  return (
+    <span
+      className={cn(
+        "text-muted-foreground inline-flex flex-wrap items-center gap-x-2.5 gap-y-0.5",
+        className,
+      )}
+    >
+      {SPEED_LEGEND.map((item) => (
+        <span className="inline-flex items-center gap-1" key={item.label}>
+          <span
+            aria-hidden
+            className="inline-block size-2 shrink-0 rounded-full"
+            style={{ backgroundColor: item.color }}
+          />
+          {item.label}
+        </span>
+      ))}
+    </span>
+  );
+}
+
 export function SpeedPill({ metric }: { metric: MessageMetric }) {
   const fill = Math.max(0, Math.min(1, metric.tokensPerSec / FULL_SCALE_TOKENS_PER_SEC));
   const { color, label } = classifySpeed(metric.tokensPerSec);
@@ -132,6 +170,8 @@ export function MessageTokenUsage({
               {formatDuration(resolvedMetric.durationMs)}
             </span>
           )}
+          {/* 生成结束(非流式中)后常驻一行颜色含义说明。 */}
+          {!resolvedMetric.isActive && <SpeedLegend className="basis-full" />}
         </>
       ) : null}
     </div>
diff --git a/offline-backend-20260512/backend/packages/harness/deerflow/persistence/task_buttons/model.py b/offline-backend-20260512/backend/packages/harness/deerflow/persistence/task_buttons/model.py
index 838eadc0..be18d180 100644
--- a/offline-backend-20260512/backend/packages/harness/deerflow/persistence/task_buttons/model.py
+++ b/offline-backend-20260512/backend/packages/harness/deerflow/persistence/task_buttons/model.py
@@ -50,7 +50,10 @@ class TaskButtonRow(Base):
     open_mode: Mapped[str | None] = mapped_column(String(16), default="blank")
     # ``url`` 跳转是否追加登录态（token 登录的上游 token + 登录用户名），供外链所在的外部系统
     # 校验当前登录用户。仅 token 登录（前端存有 token1）时实际拼上；非 token 登录自动跳过。
-    append_auth: Mapped[bool] = mapped_column(Boolean, default=False)
+    # ``server_default`` 必须显式声明：否则在已存在 ``task_buttons`` 表的旧库上，
+    # 启动期自动补列 ``_ensure_orm_columns_sync`` 会跳过「NOT NULL 且无 server_default」
+    # 的列（见 engine.py），导致该列永远补不上 → GET 查询报 Unknown column → 500。
+    append_auth: Mapped[bool] = mapped_column(Boolean, default=False, server_default="0")
     # 追加 token / 用户名的查询参数名。可空，读时归一化为 ``token`` / ``username``。
     auth_token_param: Mapped[str | None] = mapped_column(String(64), default="token")
     auth_name_param: Mapped[str | None] = mapped_column(String(64), default="username")