diff --git a/studio/frontend/src/features/chat/components/chat-search-dialog.tsx b/studio/frontend/src/features/chat/components/chat-search-dialog.tsx
index e6f51e2da8..cbd02d2bae 100644
--- a/studio/frontend/src/features/chat/components/chat-search-dialog.tsx
+++ b/studio/frontend/src/features/chat/components/chat-search-dialog.tsx
@@ -12,23 +12,32 @@ import { Cancel01Icon, Message01Icon, Search01Icon } from "@hugeicons/core-free-
 import { HugeiconsIcon } from "@hugeicons/react";
 import { useNavigate } from "@tanstack/react-router";
 import { Command as CommandPrimitive } from "cmdk";
-import { useEffect } from "react";
+import { useEffect, useMemo, useState } from "react";
 import { useChatSearchIndex } from "../hooks/use-chat-search-index";
 import { useChatSearchStore } from "../stores/chat-search-store";
 
-// cmdk's default fuzzy scorer keeps non-matching rows visible (issue #5572), so
-// require every whitespace token to be a substring of the item's keywords.
-// `value` is the unique thread id (cmdk selection); title/preview come via keywords.
-export function chatSearchFilter(
-  _value: string,
-  search: string,
-  keywords?: string[],
-): number {
-  const query = search.trim().toLowerCase();
-  if (query === "") return 1;
-  const haystack = (keywords ?? []).join(" ").toLowerCase();
-  const tokens = query.split(/\s+/);
-  return tokens.every((token) => haystack.includes(token)) ? 1 : 0;
+// Lowercased whitespace tokens of the query (haystacks are lowercased in the index).
+function queryTokens(search: string): string[] {
+  return search.trim().toLowerCase().split(/\s+/).filter(Boolean);
+}
+
+function haystackMatches(haystack: string, tokens: string[]): boolean {
+  return tokens.every((token) => haystack.includes(token));
+}
+
+// We filter rows here (cmdk runs with shouldFilter=false) so we control the
+// two-tier behavior and avoid cmdk's fuzzy scorer keeping non-matches visible
+// (issue #5572): every whitespace token must be a substring. User messages are
+// searched first; expand to the full conversation only when user text alone
+// matches nothing anywhere (user messages are short, assistant replies can be huge).
+export function selectVisibleChats<
+  T extends { userSearchText: string; searchText: string },
+>(items: T[], search: string): T[] {
+  const tokens = queryTokens(search);
+  if (tokens.length === 0) return items;
+  const userHits = items.filter((it) => haystackMatches(it.userSearchText, tokens));
+  if (userHits.length > 0) return userHits;
+  return items.filter((it) => haystackMatches(it.searchText, tokens));
 }
 
 function formatRelative(createdAt: number): string {
@@ -46,6 +55,16 @@ export function ChatSearchDialog() {
   const close = useChatSearchStore((s) => s.close);
   const navigate = useNavigate();
   const { items, loading } = useChatSearchIndex(isOpen);
+  const [query, setQuery] = useState("");
+
+  const visibleItems = useMemo(
+    () => selectVisibleChats(items, query),
+    [items, query],
+  );
+
+  useEffect(() => {
+    if (!isOpen) setQuery("");
+  }, [isOpen]);
 
   useEffect(() => {
     const handler = (e: KeyboardEvent) => {
@@ -67,7 +86,7 @@ export function ChatSearchDialog() {
       className="chat-search-surface rounded-3xl! top-1/2 -translate-y-1/2 w-[635px] max-w-[calc(100%-2rem)] gap-0 p-0 ring-0 sm:max-w-[635px]"
       overlayClassName="bg-transparent"
     >
-      <Command className="rounded-3xl p-0" filter={chatSearchFilter}>
+      <Command className="rounded-3xl p-0" shouldFilter={false}>
         <div className="flex items-center gap-3 border-b border-border/40 px-4 py-3">
           <HugeiconsIcon
             icon={Search01Icon}
@@ -76,6 +95,7 @@ export function ChatSearchDialog() {
           />
           <CommandPrimitive.Input
             placeholder="Search chats..."
+            onValueChange={setQuery}
             className="flex-1 bg-transparent text-sm outline-none placeholder:text-muted-foreground"
           />
           <button
@@ -96,11 +116,10 @@ export function ChatSearchDialog() {
                 : "No chats match."}
           </CommandEmpty>
           <CommandGroup className="p-0">
-            {items.map((item) => (
+            {visibleItems.map((item) => (
               <CommandPrimitive.Item
                 key={item.id}
                 value={item.id}
-                keywords={[item.title, item.preview]}
                 onSelect={() => {
                   navigate({
                     to: "/chat",
diff --git a/studio/frontend/src/features/chat/hooks/use-chat-search-index.ts b/studio/frontend/src/features/chat/hooks/use-chat-search-index.ts
index dc9226fb8e..841f2c2a2f 100644
--- a/studio/frontend/src/features/chat/hooks/use-chat-search-index.ts
+++ b/studio/frontend/src/features/chat/hooks/use-chat-search-index.ts
@@ -13,37 +13,72 @@ export interface ChatSearchItem {
   type: "single" | "compare";
   id: string;
   title: string;
-  preview: string;
+  // Lowercased title + user messages only (short); searched first.
+  userSearchText: string;
+  // Lowercased title + every message (incl. tool calls); fallback when user
+  // text matches nothing. Prebuilt so filtering never re-lowercases per keystroke.
+  searchText: string;
   createdAt: number;
   projectId?: string | null;
 }
 
 const THREAD_LIMIT = 200;
-const PREVIEW_MAX = 120;
 const SEARCH_REBUILD_DEBOUNCE_MS = 300;
 
+// Keys whose values are base64 image/audio payloads, not searchable text.
+const BINARY_KEY = /b64|base64|^(images?|audio|video)$/i;
+
+// Readable text from tool args/results, dropping base64 image/audio blobs so
+// they never bloat the index (object fields by key, plus data URLs / long
+// base64 runs and the "__IMAGES__" suffix inside strings).
+function searchableText(value: unknown, depth = 0): string {
+  if (typeof value === "string") {
+    const cut = value.indexOf("\n__IMAGES__:");
+    return (cut === -1 ? value : value.slice(0, cut))
+      .replace(/data:[^;,\s]+;base64,[A-Za-z0-9+/=]+/g, " ")
+      .replace(/[A-Za-z0-9+/]{120,}={0,2}/g, " ");
+  }
+  if (value == null || depth > 4) return "";
+  if (Array.isArray(value)) {
+    return value.map((v) => searchableText(v, depth + 1)).join(" ");
+  }
+  if (typeof value === "object") {
+    const out: string[] = [];
+    for (const [k, v] of Object.entries(value)) {
+      if (!BINARY_KEY.test(k)) out.push(searchableText(v, depth + 1));
+    }
+    return out.join(" ");
+  }
+  return "";
+}
+
+// Pull searchable text from a message: plain text, reasoning/thinking, tool
+// calls (name + args + result) and cited sources (title + url).
 function extractText(message: MessageRecord): string {
   const content = message.content;
   if (!Array.isArray(content)) return "";
   const parts: string[] = [];
   for (const part of content) {
     if (!part || typeof part !== "object") continue;
-    const p = part as { type?: string; text?: unknown };
-    if (
-      (p.type === "text" || p.type === "reasoning") &&
-      typeof p.text === "string"
-    ) {
+    const p = part as Record<string, unknown>;
+    if ((p.type === "text" || p.type === "reasoning") && typeof p.text === "string") {
       parts.push(p.text);
+    } else if (p.type === "thinking") {
+      const t = typeof p.thinking === "string" ? p.thinking : p.text;
+      if (typeof t === "string") parts.push(t);
+    } else if (p.type === "tool-call") {
+      if (typeof p.toolName === "string") parts.push(p.toolName);
+      const args = searchableText(typeof p.argsText === "string" ? p.argsText : p.args);
+      if (args) parts.push(args);
+      const result = searchableText(p.result);
+      if (result) parts.push(result);
+    } else if (p.type === "source") {
+      for (const v of [p.title, p.url]) if (typeof v === "string") parts.push(v);
     }
   }
   return parts.join(" ").replace(/\s+/g, " ").trim();
 }
 
-function truncate(text: string, max: number): string {
-  if (text.length <= max) return text;
-  return `${text.slice(0, max).trimEnd()}…`;
-}
-
 async function buildIndex(): Promise<ChatSearchItem[]> {
   const active = (
     await listStoredChatThreads({ includeArchived: false })
@@ -51,7 +86,10 @@ async function buildIndex(): Promise<ChatSearchItem[]> {
 
   const itemThreadIds = new Map<
     string,
-    { item: Omit<ChatSearchItem, "preview">; threadIds: string[] }
+    {
+      item: Omit<ChatSearchItem, "searchText" | "userSearchText">;
+      threadIds: string[];
+    }
   >();
   const seenPairs = new Set<string>();
 
@@ -125,15 +163,19 @@ async function buildIndex(): Promise<ChatSearchItem[]> {
     }
     merged.sort((a, b) => b.createdAt - a.createdAt);
 
-    let preview = "";
+    // Two tiers: user messages (short, searched first) and the full
+    // conversation incl. tool calls (fallback when user text matches nothing).
+    const userParts: string[] = [item.title];
+    const allParts: string[] = [item.title];
     for (const m of merged) {
       const text = extractText(m);
-      if (text) {
-        preview = truncate(text, PREVIEW_MAX);
-        break;
-      }
+      if (!text) continue;
+      allParts.push(text);
+      if (m.role === "user") userParts.push(text);
     }
-    results.push({ ...item, preview });
+    const userSearchText = userParts.join(" ").toLowerCase();
+    const searchText = allParts.join(" ").toLowerCase();
+    results.push({ ...item, userSearchText, searchText });
   }
 
   results.sort((a, b) => b.createdAt - a.createdAt);