diff --git a/apps/web/src/components/ai-sidebar/AiSidebar.tsx b/apps/web/src/components/ai-sidebar/AiSidebar.tsx
index 013b1858..39ece075 100644
--- a/apps/web/src/components/ai-sidebar/AiSidebar.tsx
+++ b/apps/web/src/components/ai-sidebar/AiSidebar.tsx
@@ -1661,7 +1661,12 @@ function AiSidebarSession({
               </Message>
               <Message from="assistant">
                 {turn.reasoning.trim() || turn.tools.length ? (
-                  <AiSidebarLocalProcess reasoning={turn.reasoning} tools={turn.tools} running={turn.status === "running"} />
+                  <AiSidebarLocalProcess
+                    reasoning={turn.reasoning}
+                    tools={turn.tools}
+                    running={turn.status === "running"}
+                    answering={turn.response.trim().length > 0 || turn.images.length > 0}
+                  />
                 ) : turn.status === "running" ? (
                   <p role="status" className="flex items-center gap-2 text-xs text-slate-500">
                     <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
diff --git a/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.test.mjs b/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.test.mjs
new file mode 100644
index 00000000..4e5e7e17
--- /dev/null
+++ b/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.test.mjs
@@ -0,0 +1,53 @@
+import { describe, expect, test } from "bun:test";
+import { createElement } from "react";
+import { renderToStaticMarkup } from "react-dom/server";
+import { createInstance } from "i18next";
+import { I18nextProvider } from "react-i18next";
+import { zhCN } from "../../../../../packages/shared/src/i18n/zh-CN.ts";
+import { AiSidebarLocalProcess } from "./AiSidebarLocalProcess.tsx";
+
+const renderProcess = async (props) => {
+  const i18n = createInstance();
+  await i18n.init({ lng: "zh-CN", resources: { "zh-CN": { translation: zhCN } } });
+  return renderToStaticMarkup(createElement(
+    I18nextProvider,
+    { i18n },
+    createElement(AiSidebarLocalProcess, props),
+  ));
+};
+
+describe("local agent thinking process", () => {
+  test("opens streamed reasoning while the agent is still thinking", async () => {
+    const markup = await renderProcess({
+      reasoning: "先按名称和价格把 12 个节点对齐。",
+      tools: [{ id: "tool-1", name: "view_file", status: "in_progress", title: "查看当前笔记" }],
+      running: true,
+    });
+    expect(markup).toContain("思考过程");
+    expect(markup).toContain("先按名称和价格把 12 个节点对齐。");
+    expect(markup).toContain('data-state="open"');
+    expect(markup).not.toContain('data-state="closed"');
+  });
+
+  test("starts collapsed once the answer is already on screen", async () => {
+    const markup = await renderProcess({
+      reasoning: "先按名称和价格把 12 个节点对齐。",
+      tools: [],
+      running: true,
+      answering: true,
+    });
+    expect(markup).toContain('data-state="closed"');
+    expect(markup).not.toContain('data-state="open"');
+  });
+
+  test("keeps a finished turn collapsed", async () => {
+    const markup = await renderProcess({
+      reasoning: "已经对过价格。",
+      tools: [],
+      running: false,
+    });
+    expect(markup).toContain("思考过程");
+    expect(markup).toContain('data-state="closed"');
+    expect(markup).not.toContain('data-state="open"');
+  });
+});
diff --git a/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.tsx b/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.tsx
index 4398e2b5..e799b6ec 100644
--- a/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.tsx
+++ b/apps/web/src/components/ai-sidebar/AiSidebarLocalProcess.tsx
@@ -1,8 +1,10 @@
 import { CollapsibleContent } from "@/components/ui/collapsible";
 import { Reasoning, ReasoningTrigger } from "@/components/ai-elements/reasoning";
 import { Loader2 } from "lucide-react";
+import { useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { AiSidebarMessage } from "./AiSidebarMessage";
+import { initialLocalProcessDisclosure, LOCAL_PROCESS_CLOSE_DELAY_MS, syncLocalProcessDisclosure, toggleLocalProcessDisclosure } from "./local-process-disclosure";
 
 type ToolRow = { id: string; name: string; status: string; title?: string };
 
@@ -29,56 +31,88 @@ function statusKey(status: string) {
   return "pending";
 }
 
-export function AiSidebarLocalProcess({ reasoning, tools, running }: { reasoning: string; tools: ToolRow[]; running: boolean }) {
+export function AiSidebarLocalProcess({ reasoning, tools, running, answering = false }: { reasoning: string; tools: ToolRow[]; running: boolean; answering?: boolean }) {
   const { t } = useTranslation();
+  const phase = { running, answering };
+  const [disclosure, setDisclosure] = useState(() => initialLocalProcessDisclosure(phase));
+  const disclosureRef = useRef(disclosure);
+  disclosureRef.current = disclosure;
+  const scroller = useRef<HTMLDivElement>(null);
+  const thinking = running && !answering;
+  useEffect(() => {
+    const next = syncLocalProcessDisclosure(disclosureRef.current, { running, answering });
+    if ("closeSoon" in next) {
+      const timer = window.setTimeout(() => {
+        setDisclosure((current) => current.heldOpen || !current.open ? current : { ...current, open: false });
+      }, LOCAL_PROCESS_CLOSE_DELAY_MS);
+      return () => window.clearTimeout(timer);
+    }
+    const current = disclosureRef.current;
+    if (next.open !== current.open || next.dismissed !== current.dismissed || next.heldOpen !== current.heldOpen) {
+      setDisclosure(next);
+    }
+  }, [running, answering]);
+  useEffect(() => {
+    const node = scroller.current;
+    if (!thinking || !disclosure.open || !node) return;
+    node.scrollTop = node.scrollHeight;
+  }, [reasoning, tools, thinking, disclosure.open]);
   if (!reasoning.trim() && !tools.length) return null;
   return (
-    <Reasoning isStreaming={running} defaultOpen={false} className="mb-2">
+    <Reasoning
+      isStreaming={thinking}
+      open={disclosure.open}
+      defaultOpen={false}
+      onOpenChange={(next) => setDisclosure((current) => toggleLocalProcessDisclosure(current, next, phase))}
+      className="mb-2"
+    >
       <ReasoningTrigger
         className="-ml-1 min-h-7 w-fit gap-1.5 rounded-sm px-1 py-1 text-xs leading-4 text-slate-500 hover:text-slate-800 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400 [&_svg]:size-3"
         getThinkingMessage={() => (
           <span className="flex items-center gap-1.5">
             {t("companion.process")}
-            {running ? <Loader2 className="size-3 animate-spin" aria-hidden="true" /> : null}
+            {thinking ? <Loader2 className="size-3 animate-spin" aria-hidden="true" /> : null}
           </span>
         )}
       />
-      <CollapsibleContent className="mt-2 max-h-80 overflow-y-auto rounded-lg border border-slate-200 bg-slate-50/70 p-3 text-xs leading-5 text-slate-600">
-        {reasoning.trim() ? (
-          <div className="[&_p]:my-1 [&_h1]:my-1 [&_h2]:my-1 [&_h3]:my-1 [&_li]:my-0">
-            <AiSidebarMessage className="text-xs leading-5">{reasoning}</AiSidebarMessage>
-          </div>
-        ) : null}
-        {tools.length ? (
-          <div className={reasoning.trim() ? "mt-3 border-t border-slate-200 pt-2" : ""}>
-            <p className="mb-1.5 text-[11px] font-medium text-slate-500">{t("aiAssistant.sidebar.processTools.activity")}</p>
-            <ul className="space-y-1.5">
-              {tools.slice(-5).map((tool) => {
-                const { label, detail } = toolSummary(tool, t);
-                const state = statusKey(tool.status);
-                return (
-                  <li key={tool.id} className="flex min-w-0 items-center gap-2">
-                    <span className={`size-1.5 shrink-0 rounded-full ${state === "running" ? "bg-sky-500" : state === "failed" ? "bg-rose-500" : "bg-slate-400"}`} aria-hidden="true" />
-                    <span className="min-w-0 flex-1 truncate">
-                      {label}{detail ? <span className="text-slate-400"> · {detail}</span> : null}
-                    </span>
-                    <span className="shrink-0 text-[11px] text-slate-400">{t(`aiAssistant.sidebar.processTools.${state}`)}</span>
-                  </li>
-                );
-              })}
-            </ul>
-            <details className="mt-2 text-[11px] text-slate-500">
-              <summary className="w-fit cursor-pointer rounded-sm hover:text-slate-800 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400">
-                {t("aiAssistant.sidebar.processTools.raw")}
-              </summary>
-              <ul className="mt-1.5 space-y-1 border-l border-slate-200 pl-2 font-mono leading-4">
-                {tools.map((tool) => (
-                  <li key={tool.id} className="break-all">{tool.title || tool.name} · {tool.status}</li>
-                ))}
+      <CollapsibleContent className="mt-2 rounded-lg border border-slate-200 bg-slate-50/70 text-xs leading-5 text-slate-600">
+        <div ref={scroller} className="max-h-80 overflow-y-auto p-3">
+          {reasoning.trim() ? (
+            <div className="[&_p]:my-1 [&_h1]:my-1 [&_h2]:my-1 [&_h3]:my-1 [&_li]:my-0">
+              <AiSidebarMessage className="text-xs leading-5" isAnimating={thinking}>{reasoning}</AiSidebarMessage>
+            </div>
+          ) : null}
+          {tools.length ? (
+            <div className={reasoning.trim() ? "mt-3 border-t border-slate-200 pt-2" : ""}>
+              <p className="mb-1.5 text-[11px] font-medium text-slate-500">{t("aiAssistant.sidebar.processTools.activity")}</p>
+              <ul className="space-y-1.5">
+                {tools.slice(-5).map((tool) => {
+                  const { label, detail } = toolSummary(tool, t);
+                  const state = statusKey(tool.status);
+                  return (
+                    <li key={tool.id} className="flex min-w-0 items-center gap-2">
+                      <span className={`size-1.5 shrink-0 rounded-full ${state === "running" ? "bg-sky-500" : state === "failed" ? "bg-rose-500" : "bg-slate-400"}`} aria-hidden="true" />
+                      <span className="min-w-0 flex-1 truncate">
+                        {label}{detail ? <span className="text-slate-400"> · {detail}</span> : null}
+                      </span>
+                      <span className="shrink-0 text-[11px] text-slate-400">{t(`aiAssistant.sidebar.processTools.${state}`)}</span>
+                    </li>
+                  );
+                })}
               </ul>
-            </details>
-          </div>
-        ) : null}
+              <details className="mt-2 text-[11px] text-slate-500">
+                <summary className="w-fit cursor-pointer rounded-sm hover:text-slate-800 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-slate-400">
+                  {t("aiAssistant.sidebar.processTools.raw")}
+                </summary>
+                <ul className="mt-1.5 space-y-1 border-l border-slate-200 pl-2 font-mono leading-4">
+                  {tools.map((tool) => (
+                    <li key={tool.id} className="break-all">{tool.title || tool.name} · {tool.status}</li>
+                  ))}
+                </ul>
+              </details>
+            </div>
+          ) : null}
+        </div>
       </CollapsibleContent>
     </Reasoning>
   );
diff --git a/apps/web/src/components/ai-sidebar/local-process-disclosure.test.mjs b/apps/web/src/components/ai-sidebar/local-process-disclosure.test.mjs
new file mode 100644
index 00000000..b8fdde25
--- /dev/null
+++ b/apps/web/src/components/ai-sidebar/local-process-disclosure.test.mjs
@@ -0,0 +1,49 @@
+import { describe, expect, test } from "bun:test";
+import {
+  initialLocalProcessDisclosure,
+  LOCAL_PROCESS_CLOSE_DELAY_MS,
+  syncLocalProcessDisclosure,
+  toggleLocalProcessDisclosure,
+} from "./local-process-disclosure.ts";
+
+const thinking = { running: true, answering: false };
+const answering = { running: true, answering: true };
+const finished = { running: false, answering: true };
+
+describe("local process disclosure", () => {
+  test("starts open only while thinking", () => {
+    expect(initialLocalProcessDisclosure(thinking).open).toBe(true);
+    expect(initialLocalProcessDisclosure(answering).open).toBe(false);
+    expect(initialLocalProcessDisclosure(finished).open).toBe(false);
+    expect(LOCAL_PROCESS_CLOSE_DELAY_MS).toBe(1000);
+  });
+
+  test("stays open through thinking and schedules a close once the answer starts", () => {
+    const open = initialLocalProcessDisclosure(thinking);
+    expect(syncLocalProcessDisclosure(open, thinking)).toEqual(open);
+    expect(syncLocalProcessDisclosure(open, answering)).toEqual({ closeSoon: true });
+    expect(syncLocalProcessDisclosure(open, finished)).toEqual({ closeSoon: true });
+  });
+
+  test("does not reopen a panel the user collapsed while thinking", () => {
+    const collapsed = toggleLocalProcessDisclosure(initialLocalProcessDisclosure(thinking), false, thinking);
+    expect(collapsed).toEqual({ open: false, dismissed: true, heldOpen: false });
+    expect(syncLocalProcessDisclosure(collapsed, thinking)).toEqual(collapsed);
+    expect(syncLocalProcessDisclosure(collapsed, answering)).toEqual(collapsed);
+  });
+
+  test("keeps a manual reopen after the answer starts", () => {
+    const closed = { open: false, dismissed: false, heldOpen: false };
+    const reopened = toggleLocalProcessDisclosure(closed, true, answering);
+    expect(reopened.heldOpen).toBe(true);
+    expect(syncLocalProcessDisclosure(reopened, answering)).toEqual(reopened);
+    expect(syncLocalProcessDisclosure(reopened, finished)).toEqual(reopened);
+  });
+
+  test("still closes when the user reopens during thinking and the answer then starts", () => {
+    const collapsed = toggleLocalProcessDisclosure(initialLocalProcessDisclosure(thinking), false, thinking);
+    const reopened = toggleLocalProcessDisclosure(collapsed, true, thinking);
+    expect(reopened).toEqual({ open: true, dismissed: false, heldOpen: false });
+    expect(syncLocalProcessDisclosure(reopened, answering)).toEqual({ closeSoon: true });
+  });
+});
diff --git a/apps/web/src/components/ai-sidebar/local-process-disclosure.ts b/apps/web/src/components/ai-sidebar/local-process-disclosure.ts
new file mode 100644
index 00000000..b40b4dcc
--- /dev/null
+++ b/apps/web/src/components/ai-sidebar/local-process-disclosure.ts
@@ -0,0 +1,41 @@
+export const LOCAL_PROCESS_CLOSE_DELAY_MS = 1000;
+
+export type LocalProcessPhase = { running: boolean; answering: boolean };
+
+export type LocalProcessDisclosure = {
+  open: boolean;
+  /** The user collapsed the panel while thinking was still the only output. */
+  dismissed: boolean;
+  /** The user reopened the panel after the answer had already started. */
+  heldOpen: boolean;
+};
+
+export const initialLocalProcessDisclosure = (phase: LocalProcessPhase): LocalProcessDisclosure => ({
+  open: phase.running && !phase.answering,
+  dismissed: false,
+  heldOpen: false,
+});
+
+export function syncLocalProcessDisclosure(
+  current: LocalProcessDisclosure,
+  phase: LocalProcessPhase,
+): LocalProcessDisclosure | { closeSoon: true } {
+  if (current.heldOpen) return current;
+  if (phase.running && !phase.answering) {
+    if (current.dismissed) return { ...current, open: false };
+    return { open: true, dismissed: false, heldOpen: false };
+  }
+  if (!current.open) return { ...current, open: false };
+  return { closeSoon: true };
+}
+
+export function toggleLocalProcessDisclosure(
+  current: LocalProcessDisclosure,
+  open: boolean,
+  phase: LocalProcessPhase,
+): LocalProcessDisclosure {
+  if (open) {
+    return { open: true, dismissed: false, heldOpen: !phase.running || phase.answering };
+  }
+  return { open: false, dismissed: phase.running && !phase.answering, heldOpen: false };
+}