diff --git a/src/server/ai/tools/get-current-time.ts b/src/server/ai/tools/get-current-time.ts
index 4077a8f..34a20e8 100644
--- a/src/server/ai/tools/get-current-time.ts
+++ b/src/server/ai/tools/get-current-time.ts
@@ -10,6 +10,7 @@ export function createGetCurrentTime(logger?: Logger) {
     inputSchema: z.object({
       timezone: z.string().optional().describe("IANA 时区名称，如 'Asia/Shanghai'、'America/New_York'"),
     }),
+    metadata: { displayName: "获取当前时间" },
   });
 }
 
diff --git a/src/web/consoles/workbench/components/chat/ChatPanel.tsx b/src/web/consoles/workbench/components/chat/ChatPanel.tsx
index 9f47098..3b815fa 100644
--- a/src/web/consoles/workbench/components/chat/ChatPanel.tsx
+++ b/src/web/consoles/workbench/components/chat/ChatPanel.tsx
@@ -1,5 +1,5 @@
 import { useChat } from "@ai-sdk/react";
-import { CopyOutlined, EditOutlined, RedoOutlined, RobotOutlined } from "@ant-design/icons";
+import { ArrowDownOutlined, CopyOutlined, EditOutlined, RedoOutlined, RobotOutlined } from "@ant-design/icons";
 import { useQueryClient } from "@tanstack/react-query";
 import { DefaultChatTransport, type UIMessage } from "ai";
 import { App, Button, Card, Flex, Input, Spin, Typography } from "antd";
@@ -17,6 +17,7 @@ import { ChatInputArea } from "./ChatInputArea";
 import { ReasoningPart } from "./parts/ReasoningPart";
 import { TextPart } from "./parts/TextPart";
 import { ToolPart } from "./parts/ToolPart";
+import { useChatScroll } from "./use-chat-scroll";
 
 interface ChatPanelProps {
   conversationId: null | string;
@@ -55,6 +56,8 @@ export function ChatPanel({ conversationId, onConversationCreated, projectId }:
 
   const isLoading = status === "submitted" || status === "streaming";
 
+  const { isAtBottom, scrollToBottom } = useChatScroll({ messages, scrollRef, status });
+
   useEffect(() => {
     if (!conversationId) {
       setMessages([]);
@@ -125,10 +128,6 @@ export function ChatPanel({ conversationId, onConversationCreated, projectId }:
       });
   }, [conversationId, textModels, projectId, logger]);
 
-  useEffect(() => {
-    scrollRef.current?.scrollTo({ behavior: "smooth", top: scrollRef.current.scrollHeight });
-  }, [messages]);
-
   useEffect(() => {
     if (status === "ready" && conversationId) {
       void queryClient.invalidateQueries({ queryKey: ["conversations", projectId] });
@@ -380,6 +379,15 @@ export function ChatPanel({ conversationId, onConversationCreated, projectId }:
           </Flex>
         </div>
       )}
+      {!isAtBottom && (
+        <Button
+          className="chat-scroll-bottom-btn"
+          icon={<ArrowDownOutlined />}
+          onClick={scrollToBottom}
+          shape="circle"
+          size="small"
+        />
+      )}
       <ChatInputArea
         displayModelId={displayModelId}
         input={input}
diff --git a/src/web/consoles/workbench/components/chat/parts/ReasoningPart.tsx b/src/web/consoles/workbench/components/chat/parts/ReasoningPart.tsx
index c681182..6d06116 100644
--- a/src/web/consoles/workbench/components/chat/parts/ReasoningPart.tsx
+++ b/src/web/consoles/workbench/components/chat/parts/ReasoningPart.tsx
@@ -1,20 +1,40 @@
 import { CheckCircleFilled, LoadingOutlined } from "@ant-design/icons";
 import { Collapse, Flex, Typography } from "antd";
+import { useCallback, useMemo, useState } from "react";
 
 import type { PartProps } from "./types";
 
+const REASONING_KEY = "reasoning";
+
 export function ReasoningPart({ part }: PartProps) {
   const text = typeof part["text"] === "string" ? part["text"] : "";
   const state = typeof part["state"] === "string" ? part["state"] : "";
   const isStreaming = state === "streaming";
 
+  const [userToggled, setUserToggled] = useState(false);
+  const [userActiveKey, setUserActiveKey] = useState<string[]>([]);
+
+  const autoActiveKey = useMemo(() => {
+    if (isStreaming) return [REASONING_KEY];
+    if (state === "complete" || text.length > 0) return [];
+    return [];
+  }, [isStreaming, state, text]);
+
+  const activeKey = userToggled ? userActiveKey : autoActiveKey;
+
+  const handleChange = useCallback((keys: string | string[]) => {
+    setUserToggled(true);
+    setUserActiveKey(keys as string[]);
+  }, []);
+
   return (
     <Collapse
+      activeKey={activeKey}
       ghost
       items={[
         {
           children: <Typography.Text type="secondary">{text}</Typography.Text>,
-          key: "reasoning",
+          key: REASONING_KEY,
           label: isStreaming ? (
             <Flex align="center" component="span" gap={4}>
               <LoadingOutlined className="icon-primary" />
@@ -28,6 +48,7 @@ export function ReasoningPart({ part }: PartProps) {
           ),
         },
       ]}
+      onChange={handleChange}
       size="small"
     />
   );
diff --git a/src/web/consoles/workbench/components/chat/parts/TextPart.tsx b/src/web/consoles/workbench/components/chat/parts/TextPart.tsx
index 7c703a4..320de35 100644
--- a/src/web/consoles/workbench/components/chat/parts/TextPart.tsx
+++ b/src/web/consoles/workbench/components/chat/parts/TextPart.tsx
@@ -1,8 +1,25 @@
+import type { ComponentType, SVGProps } from "react";
+
+import { CheckOutlined, CopyOutlined, DownloadOutlined } from "@ant-design/icons";
 import { Typography } from "antd";
 import { Streamdown } from "streamdown";
 
 import type { PartProps } from "./types";
 
+type IconComponent = ComponentType<SVGProps<SVGSVGElement> & { size?: number }>;
+
+const STREAMDOWN_ICONS: Partial<Record<"CheckIcon" | "CopyIcon" | "DownloadIcon", IconComponent>> = {
+  CheckIcon: CheckOutlined as IconComponent,
+  CopyIcon: CopyOutlined as IconComponent,
+  DownloadIcon: DownloadOutlined as IconComponent,
+};
+
+const STREAMDOWN_TRANSLATIONS = {
+  copied: "已复制",
+  copyCode: "复制",
+  downloadFile: "下载",
+};
+
 interface TextPartProps extends PartProps {
   role: string;
 }
@@ -15,7 +32,9 @@ export function TextPart({ part, role }: TextPartProps) {
       {role === "user" ? (
         <Typography.Paragraph className="message-body-text">{text}</Typography.Paragraph>
       ) : (
-        <Streamdown parseIncompleteMarkdown>{text}</Streamdown>
+        <Streamdown icons={STREAMDOWN_ICONS} parseIncompleteMarkdown translations={STREAMDOWN_TRANSLATIONS}>
+          {text}
+        </Streamdown>
       )}
     </div>
   );
diff --git a/src/web/consoles/workbench/components/chat/parts/ToolPart.tsx b/src/web/consoles/workbench/components/chat/parts/ToolPart.tsx
index a5c760c..87db9d0 100644
--- a/src/web/consoles/workbench/components/chat/parts/ToolPart.tsx
+++ b/src/web/consoles/workbench/components/chat/parts/ToolPart.tsx
@@ -8,6 +8,7 @@ interface ToolPartData {
   input?: unknown;
   output?: unknown;
   toolCallId?: string;
+  toolMetadata?: Record<string, unknown>;
   toolName?: string;
   type?: string;
 }
@@ -24,7 +25,9 @@ const FORMAT_JSON = (v: unknown) => JSON.stringify(v, null, 2);
 export function ToolPart({ part }: PartProps) {
   const toolPart = part as unknown as ToolPartData;
   const state = getToolState(toolPart);
-  const toolName = toolPart.toolName ?? (toolPart.type ?? "unknown").replace(/^tool-/, "");
+  const rawToolName = toolPart.toolName ?? (toolPart.type ?? "unknown").replace(/^tool-/, "");
+  const toolName =
+    typeof toolPart.toolMetadata?.["displayName"] === "string" ? toolPart.toolMetadata["displayName"] : rawToolName;
 
   const isStreaming = state === "input-streaming" || state === "input-available";
 
diff --git a/src/web/consoles/workbench/components/chat/use-chat-scroll.ts b/src/web/consoles/workbench/components/chat/use-chat-scroll.ts
new file mode 100644
index 0000000..570a6ce
--- /dev/null
+++ b/src/web/consoles/workbench/components/chat/use-chat-scroll.ts
@@ -0,0 +1,55 @@
+import type { UIMessage } from "ai";
+
+import { useCallback, useEffect, useState } from "react";
+
+const NEAR_BOTTOM_THRESHOLD = 80;
+
+interface UseChatScrollOptions {
+  messages: UIMessage[];
+  scrollRef: React.RefObject<HTMLDivElement | null>;
+  status: string;
+}
+
+export function useChatScroll({ messages, scrollRef, status }: UseChatScrollOptions) {
+  const [isAtBottom, setIsAtBottom] = useState(true);
+  const isStreaming = status === "streaming";
+
+  const checkNearBottom = useCallback(() => {
+    const el = scrollRef.current;
+    if (!el) return true;
+    return el.scrollHeight - el.scrollTop - el.clientHeight < NEAR_BOTTOM_THRESHOLD;
+  }, [scrollRef]);
+
+  useEffect(() => {
+    const el = scrollRef.current;
+    if (!el) return;
+
+    setIsAtBottom(checkNearBottom());
+
+    const handleScroll = () => {
+      setIsAtBottom(checkNearBottom());
+    };
+
+    el.addEventListener("scroll", handleScroll, { passive: true });
+    return () => el.removeEventListener("scroll", handleScroll);
+  }, [scrollRef, checkNearBottom]);
+
+  useEffect(() => {
+    const el = scrollRef.current;
+    if (!el || !isAtBottom) return;
+
+    el.scrollTo({
+      behavior: isStreaming ? "instant" : "smooth",
+      top: el.scrollHeight,
+    });
+  }, [messages, isStreaming, isAtBottom, scrollRef]);
+
+  const scrollToBottom = useCallback(() => {
+    const el = scrollRef.current;
+    if (!el) return;
+    el.scrollTo({ behavior: "smooth", top: el.scrollHeight });
+    setIsAtBottom(true);
+  }, [scrollRef]);
+
+  return { isAtBottom, scrollToBottom };
+}
diff --git a/src/web/styles.css b/src/web/styles.css
index e30dfca..3fd6bb8 100644
--- a/src/web/styles.css
+++ b/src/web/styles.css
@@ -141,6 +141,7 @@ body {
   flex-direction: column;
   min-height: 0;
   min-width: 0;
+  position: relative;
 }
 
 .chat-welcome-area {
@@ -251,6 +252,47 @@ body {
   color: var(--ant-color-text-secondary);
 }
 
+.chat-scroll-bottom-btn {
+  position: absolute;
+  bottom: 115px;
+  left: 50%;
+  transform: translateX(-50%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 10;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
+}
+
+[data-streamdown="code-block-actions"] {
+  gap: 4px;
+}
+
+[data-streamdown="code-block-actions"] button {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 28px;
+  height: 28px;
+  padding: 0 6px;
+  border-radius: var(--ant-border-radius-sm);
+  border: 1px solid var(--ant-color-border-secondary);
+  background: var(--ant-color-bg-container);
+  color: var(--ant-color-text-secondary);
+  font-size: 12px;
+  transition: all 0.2s;
+}
+
+[data-streamdown="code-block-actions"] button:hover {
+  color: var(--ant-color-primary);
+  border-color: var(--ant-color-primary);
+}
+
+[data-streamdown="code-block-actions"] button svg {
+  width: 14px;
+  height: 14px;
+}
+
 .app-page-flex {
   flex: 1;
 }
diff --git a/tests/web/components/chat/ReasoningPart.test.tsx b/tests/web/components/chat/ReasoningPart.test.tsx
new file mode 100644
index 0000000..9ddba2e
--- /dev/null
+++ b/tests/web/components/chat/ReasoningPart.test.tsx
@@ -0,0 +1,49 @@
+import { fireEvent, screen } from "@testing-library/react";
+import { describe, expect, test } from "bun:test";
+import { createElement } from "react";
+
+import { ReasoningPart } from "../../../../src/web/consoles/workbench/components/chat/parts/ReasoningPart";
+import { renderWithProviders } from "../../test-utils";
+
+describe("ReasoningPart", () => {
+  test("流式状态时自动展开显示文本", () => {
+    const part = { state: "streaming", text: "正在思考...", type: "reasoning" };
+
+    renderWithProviders(createElement(ReasoningPart, { part }));
+
+    expect(screen.getByText("正在思考...")).toBeTruthy();
+    expect(screen.getByText("思考中")).toBeTruthy();
+  });
+
+  test("完成状态时显示思考完成标签", () => {
+    const part = { state: "complete", text: "思考内容", type: "reasoning" };
+
+    renderWithProviders(createElement(ReasoningPart, { part }));
+
+    expect(screen.getByText("思考完成")).toBeTruthy();
+  });
+
+  test("无状态时默认收起", () => {
+    const part = { text: "默认内容", type: "reasoning" };
+
+    const { container } = renderWithProviders(createElement(ReasoningPart, { part }));
+
+    const expanded = container.querySelector('[aria-expanded="true"]');
+    expect(expanded).toBeNull();
+  });
+
+  test("用户点击折叠后尊重用户意图", () => {
+    const part = { state: "streaming", text: "思考中内容", type: "reasoning" };
+
+    const { container } = renderWithProviders(createElement(ReasoningPart, { part }));
+
+    const collapseHeader = container.querySelector(".ant-collapse-header");
+    expect(collapseHeader).toBeTruthy();
+
+    if (collapseHeader) {
+      fireEvent.click(collapseHeader);
+    }
+
+    expect(screen.getByText("思考中内容")).toBeTruthy();
+  });
+});
diff --git a/tests/web/components/chat/ToolPart.test.tsx b/tests/web/components/chat/ToolPart.test.tsx
new file mode 100644
index 0000000..245a6c2
--- /dev/null
+++ b/tests/web/components/chat/ToolPart.test.tsx
@@ -0,0 +1,65 @@
+import { screen } from "@testing-library/react";
+import { describe, expect, test } from "bun:test";
+import { createElement } from "react";
+
+import { ToolPart } from "../../../../src/web/consoles/workbench/components/chat/parts/ToolPart";
+import { renderWithProviders } from "../../test-utils";
+
+describe("ToolPart 工具显示名", () => {
+  test("无 toolMetadata 时使用 toolName", () => {
+    const part = {
+      input: { timezone: "Asia/Shanghai" },
+      output: { iso: "2024-01-01T00:00:00.000Z", local: "2024年1月1日", timestamp: 1704067200000 },
+      toolCallId: "call-1",
+      toolName: "getCurrentTime",
+      type: "tool-getCurrentTime",
+    };
+
+    renderWithProviders(createElement(ToolPart, { part }));
+
+    expect(screen.getByText(/getCurrentTime/)).toBeTruthy();
+  });
+
+  test("有 toolMetadata.displayName 时优先使用显示名", () => {
+    const part = {
+      input: { timezone: "Asia/Shanghai" },
+      output: { iso: "2024-01-01T00:00:00.000Z", local: "2024年1月1日", timestamp: 1704067200000 },
+      toolCallId: "call-1",
+      toolMetadata: { displayName: "获取当前时间" },
+      toolName: "getCurrentTime",
+      type: "tool-getCurrentTime",
+    };
+
+    renderWithProviders(createElement(ToolPart, { part }));
+
+    expect(screen.getByText("获取当前时间")).toBeTruthy();
+    expect(screen.queryByText(/getCurrentTime/)).toBeNull();
+  });
+
+  test("toolMetadata.displayName 非字符串时回退到 toolName", () => {
+    const part = {
+      input: {},
+      output: {},
+      toolCallId: "call-2",
+      toolMetadata: { displayName: 123 },
+      type: "tool-someTool",
+    };
+
+    renderWithProviders(createElement(ToolPart, { part }));
+
+    expect(screen.getByText("someTool")).toBeTruthy();
+  });
+
+  test("错误状态时使用显示名", () => {
+    const part = {
+      errorText: "超时",
+      toolCallId: "call-3",
+      toolMetadata: { displayName: "获取当前时间" },
+      type: "tool-getCurrentTime",
+    };
+
+    renderWithProviders(createElement(ToolPart, { part }));
+
+    expect(screen.getByText(/获取当前时间.*失败/)).toBeTruthy();
+  });
+});
diff --git a/tests/web/hooks/use-chat-scroll.test.ts b/tests/web/hooks/use-chat-scroll.test.ts
new file mode 100644
index 0000000..73779a4
--- /dev/null
+++ b/tests/web/hooks/use-chat-scroll.test.ts
@@ -0,0 +1,137 @@
+import type { UIMessage } from "ai";
+
+import { act, renderHook } from "@testing-library/react";
+import { describe, expect, mock, test } from "bun:test";
+
+import { useChatScroll } from "../../../src/web/consoles/workbench/components/chat/use-chat-scroll";
+
+interface MockedElement {
+  addEventListener: ReturnType<typeof mock>;
+  clientHeight: number;
+  removeEventListener: ReturnType<typeof mock>;
+  scrollHeight: number;
+  scrollTo: ReturnType<typeof mock>;
+  scrollTop: number;
+}
+
+function asHTMLElement(el: MockedElement): HTMLElement {
+  return el as unknown as HTMLElement;
+}
+
+function asRef(el: MockedElement): React.RefObject<HTMLElement | null> {
+  return { current: asHTMLElement(el) };
+}
+
+function createScrollElement(overrides: Partial<MockedElement> = {}): MockedElement {
+  return {
+    addEventListener: mock(() => {}),
+    clientHeight: 400,
+    removeEventListener: mock(() => {}),
+    scrollHeight: 1000,
+    scrollTo: mock(() => {}),
+    scrollTop: 600,
+    ...overrides,
+  };
+}
+
+describe("useChatScroll", () => {
+  test("在底部附近时自动滚动", () => {
+    const el = createScrollElement({ scrollHeight: 1000, scrollTop: 920 });
+    const scrollRef = asRef(el);
+    const messages: UIMessage[] = [{ id: "1", parts: [], role: "user" }] as UIMessage[];
+
+    const { rerender } = renderHook(
+      ({
+        messages,
+        scrollRef,
+        status,
+      }: {
+        messages: UIMessage[];
+        scrollRef: React.RefObject<HTMLElement | null>;
+        status: string;
+      }) => useChatScroll({ messages, scrollRef, status }),
+      {
+        initialProps: { messages, scrollRef, status: "streaming" },
+      },
+    );
+
+    const newMessages: UIMessage[] = [
+      { id: "1", parts: [], role: "user" },
+      { id: "2", parts: [], role: "assistant" },
+    ] as UIMessage[];
+
+    rerender({ messages: newMessages, scrollRef, status: "streaming" });
+
+    expect(el.scrollTo).toHaveBeenCalled();
+  });
+
+  test("不在底部时不自动滚动", () => {
+    const el = createScrollElement({ scrollHeight: 1000, scrollTop: 200 });
+    const scrollRef = asRef(el);
+    const messages: UIMessage[] = [{ id: "1", parts: [], role: "user" }] as UIMessage[];
+
+    const { rerender } = renderHook(
+      ({
+        messages,
+        scrollRef,
+        status,
+      }: {
+        messages: UIMessage[];
+        scrollRef: React.RefObject<HTMLElement | null>;
+        status: string;
+      }) => useChatScroll({ messages, scrollRef, status }),
+      {
+        initialProps: { messages, scrollRef, status: "streaming" },
+      },
+    );
+
+    const handlerCalls = el.addEventListener.mock.calls as unknown[][];
+    const scrollHandler = handlerCalls.find((c) => c[0] === "scroll")?.[1];
+
+    if (scrollHandler) {
+      el.scrollTop = 200;
+      (scrollHandler as () => void)();
+    }
+
+    el.scrollTo.mockClear();
+
+    const newMessages: UIMessage[] = [
+      { id: "1", parts: [], role: "user" },
+      { id: "2", parts: [], role: "assistant" },
+    ] as UIMessage[];
+
+    rerender({ messages: newMessages, scrollRef, status: "streaming" });
+
+    const scrollToCalls = el.scrollTo.mock.calls as unknown[][];
+    expect(scrollToCalls.length).toBe(0);
+  });
+
+  test("scrollToBottom 使用 smooth 滚动", () => {
+    const el = createScrollElement({ scrollHeight: 1000, scrollTop: 200 });
+    const scrollRef = asRef(el);
+    const messages: UIMessage[] = [];
+
+    const { result } = renderHook(() => useChatScroll({ messages, scrollRef, status: "ready" }));
+
+    act(() => {
+      result.current.scrollToBottom();
+    });
+
+    expect(el.scrollTo).toHaveBeenCalledWith({ behavior: "smooth", top: 1000 });
+  });
+
+  test("流式时使用 instant 滚动", () => {
+    const el = createScrollElement({ scrollHeight: 1000, scrollTop: 920 });
+    const scrollRef = asRef(el);
+    const messages: UIMessage[] = [{ id: "1", parts: [], role: "user" }] as UIMessage[];
+
+    renderHook(() => useChatScroll({ messages, scrollRef, status: "streaming" }));
+
+    const calls = el.scrollTo.mock.calls as unknown[][];
+    const instantCall = calls.find((call) => {
+      const opts = call[0] as Record<string, unknown> | undefined;
+      return opts?.["behavior"] === "instant";
+    });
+    expect(instantCall).toBeTruthy();
+  });
+});