diff --git a/app/(docs)/@docs/[lang]/[pageId]/chatForm.tsx b/app/(docs)/@docs/[lang]/[pageId]/chatForm.tsx
index f38ce7ee..1a1abb6e 100644
--- a/app/(docs)/@docs/[lang]/[pageId]/chatForm.tsx
+++ b/app/(docs)/@docs/[lang]/[pageId]/chatForm.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, FormEvent, useEffect } from "react";
+import { useState, FormEvent, useEffect, useRef, useCallback } from "react";
 // import useSWR from "swr";
 // import {
 //   getQuestionExample,
@@ -9,9 +9,10 @@ import { useState, FormEvent, useEffect } from "react";
 // import { getLanguageName } from "../pagesList";
 import { useEmbedContext } from "@/terminal/embedContext";
 import { DynamicMarkdownSection, PagePath } from "@/lib/docs";
-import { useRouter } from "next/navigation";
+import { usePathname, useRouter } from "next/navigation";
 import { ChatStreamEvent } from "@/api/chat/route";
 import { useStreamingChatContext } from "@/(docs)/streamingChatContext";
+import { revalidateChatAction } from "@/actions/revalidateChat";
 
 interface ChatFormProps {
   path: PagePath;
@@ -32,6 +33,37 @@ export function ChatForm({ path, sectionContent, close }: ChatFormProps) {
   const router = useRouter();
   const streamingChatContext = useStreamingChatContext();
 
+  const pathname = usePathname();
+  const pendingRouterPushTarget = useRef<null | string>(null);
+  const pendingRouterPushResolver = useRef<null | (() => void)>(null);
+  // router.pushの完了を待つ関数。pathnameの変化でページ遷移の完了を検知し、解決する。
+  const asyncRouterPush = useCallback(
+    (url: string, options?: { scroll?: boolean }) => {
+      if (pendingRouterPushTarget.current) {
+        console.error(
+          "Already navigating to",
+          pendingRouterPushTarget.current,
+          "can't navigate to",
+          url
+        );
+        return;
+      }
+      pendingRouterPushTarget.current = url;
+      return new Promise<void>((resolve) => {
+        pendingRouterPushResolver.current = resolve;
+        router.push(url, options);
+      });
+    },
+    [router]
+  );
+  useEffect(() => {
+    if (pendingRouterPushTarget.current === pathname) {
+      pendingRouterPushResolver.current?.();
+      pendingRouterPushTarget.current = null;
+      pendingRouterPushResolver.current = null;
+    }
+  }, [pathname]);
+
   // const documentContentInView = sectionContent
   //   .filter((s) => s.inView)
   //   .map((s) => s.rawContent)
@@ -98,6 +130,7 @@ export function ChatForm({ path, sectionContent, close }: ChatFormProps) {
     const reader = response.body!.getReader();
     const decoder = new TextDecoder();
     let buffer = "";
+    let chatId: string | null = null;
     let navigated = false;
 
     // ストリームを非同期で読み続ける（ナビゲーション後もバックグラウンドで継続）
@@ -118,11 +151,16 @@ export function ChatForm({ path, sectionContent, close }: ChatFormProps) {
               const event = JSON.parse(line) as ChatStreamEvent;
 
               if (event.type === "chat") {
+                // revalidateChatは/api/chatの中では呼ばず、別のServerActionとして呼び出す
+                await revalidateChatAction(event.chatId, path);
+                chatId = event.chatId;
                 streamingChatContext.startStreaming(event.chatId);
                 document.getElementById(event.sectionId)?.scrollIntoView({
                   behavior: "smooth",
                 });
-                router.push(`/chat/${event.chatId}`, { scroll: false });
+                await asyncRouterPush(`/chat/${event.chatId}`, {
+                  scroll: false,
+                });
                 router.refresh();
                 navigated = true;
                 setIsLoading(false);
@@ -131,6 +169,9 @@ export function ChatForm({ path, sectionContent, close }: ChatFormProps) {
               } else if (event.type === "chunk") {
                 streamingChatContext.appendChunk(event.text);
               } else if (event.type === "done") {
+                if (chatId) {
+                  await revalidateChatAction(chatId, path);
+                }
                 streamingChatContext.finishStreaming();
                 router.refresh();
               } else if (event.type === "error") {
@@ -138,7 +179,11 @@ export function ChatForm({ path, sectionContent, close }: ChatFormProps) {
                   setErrorMessage(event.message);
                   setIsLoading(false);
                 }
+                if (chatId) {
+                  await revalidateChatAction(chatId, path);
+                }
                 streamingChatContext.finishStreaming();
+                router.refresh();
               }
             } catch {
               // ignore JSON parse errors
diff --git a/app/actions/deleteChat.ts b/app/actions/deleteChat.ts
index 65ec9507..9edcac82 100644
--- a/app/actions/deleteChat.ts
+++ b/app/actions/deleteChat.ts
@@ -1,10 +1,22 @@
 "use server";
 
 import { z } from "zod";
-import { deleteChat, initContext } from "@/lib/chatHistory";
+import { deleteChat, initContext, revalidateChat } from "@/lib/chatHistory";
+import { section } from "@/schema/chat";
+import { eq } from "drizzle-orm";
 
 export async function deleteChatAction(chatId: string) {
   chatId = z.uuid().parse(chatId);
   const ctx = await initContext();
-  await deleteChat(chatId, ctx);
+  if (!ctx.userId) {
+    throw new Error("Not authenticated");
+  }
+  const deletedChat = await deleteChat(chatId, ctx);
+
+  const targetSection = await ctx.drizzle.query.section.findFirst({
+    where: eq(section.sectionId, deletedChat[0].sectionId),
+  });
+  if (targetSection) {
+    await revalidateChat(chatId, ctx.userId, targetSection.pagePath);
+  }
 }
diff --git a/app/actions/revalidateChat.ts b/app/actions/revalidateChat.ts
new file mode 100644
index 00000000..1f502ece
--- /dev/null
+++ b/app/actions/revalidateChat.ts
@@ -0,0 +1,26 @@
+"use server";
+
+import { initContext, revalidateChat } from "@/lib/chatHistory";
+import { PagePath, PagePathSchema } from "@/lib/docs";
+import { z } from "zod";
+
+export async function revalidateChatAction(
+  chatId: string,
+  pagePath: string | PagePath
+) {
+  chatId = z.uuid().parse(chatId);
+  if (typeof pagePath === "string") {
+    if (!/^[a-z0-9_-]+\/[a-z0-9_-]+$/.test(pagePath)) {
+      throw new Error("Invalid pagePath format");
+    }
+    const [lang, page] = pagePath.split("/");
+    pagePath = PagePathSchema.parse({ lang, page });
+  } else {
+    pagePath = PagePathSchema.parse(pagePath);
+  }
+  const ctx = await initContext();
+  if (!ctx.userId) {
+    throw new Error("Not authenticated");
+  }
+  await revalidateChat(chatId, ctx.userId, pagePath);
+}
diff --git a/app/lib/chatHistory.ts b/app/lib/chatHistory.ts
index c2182006..e1392102 100644
--- a/app/lib/chatHistory.ts
+++ b/app/lib/chatHistory.ts
@@ -28,7 +28,11 @@ export function cacheKeyForChat(chatId: string) {
   return `${CACHE_KEY_BASE}/getChatOne?chatId=${chatId}`;
 }
 
-async function revalidateChat(
+// nextjsのキャッシュのrevalidateはRouteHandlerではなくServerActionから呼ばないと正しく動作しないらしい。
+// https://github.com/vercel/next.js/issues/69064
+// そのためlib/以下の関数では直接revalidateChatを呼ばず、ServerActionの関数から呼ぶようにする。
+// Nextjs 16 に更新したらこれをupdateTag()で置き換える。
+export async function revalidateChat(
   chatId: string,
   userId: string,
   pagePath: string | PagePath
@@ -126,8 +130,6 @@ export async function addChat(
     chatDiffs = [] as never[];
   }
 
-  await revalidateChat(newChat.chatId, userId, path);
-
   return {
     ...newChat,
     section: {
@@ -173,8 +175,6 @@ export async function addMessagesAndDiffs(
       }))
     );
   }
-
-  await revalidateChat(chatId, userId, path);
 }
 
 export async function deleteChat(chatId: string, context: Context) {
@@ -192,10 +192,7 @@ export async function deleteChat(chatId: string, context: Context) {
   await drizzle.delete(message).where(eq(message.chatId, chatId));
   await drizzle.delete(diff).where(eq(diff.chatId, chatId));
 
-  const targetSection = await drizzle.query.section.findFirst({
-    where: eq(section.sectionId, deletedChat[0].sectionId),
-  });
-  await revalidateChat(chatId, userId, targetSection?.pagePath ?? "");
+  return deletedChat;
 }
 
 export async function getAllChat(