diff --git a/src/App.css b/src/App.css
index f75d1e5..4eb40f9 100644
--- a/src/App.css
+++ b/src/App.css
@@ -359,3 +359,71 @@ pre {
   .main { grid-template-columns: 1fr; }
   .panel-left { border-right: none; border-bottom: 1px solid var(--border); }
 }
+/* ─── Server Group ─────────────────────────────────────────── */
+.server-group {
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  margin-bottom: 16px;
+  overflow: hidden;
+}
+
+.server-group-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 10px 14px;
+  cursor: pointer;
+  background: var(--surface);
+}
+
+.server-group-title {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.server-host-sub {
+  font-size: 0.75rem;
+  opacity: 0.6;
+}
+
+.server-status-dot {
+  width: 10px;
+  height: 10px;
+  border-radius: 50%;
+}
+.dot-ok      { background: #22c55e; }
+.dot-err     { background: #ef4444; }
+.dot-pending { background: #f59e0b; }
+
+.group-ok   { border-color: #22c55e44; }
+.group-err  { border-color: #ef444444; }
+
+.server-group-results {
+  padding: 8px;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.server-group-meta {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.group-chevron {
+  font-size: 11px;
+  color: var(--muted);
+}
+
+.server-errors {
+  font-family: var(--font-mono);
+  font-size: 11px;
+  color: var(--muted);
+}
+
+.group-err .server-errors {
+  color: var(--err);
+  font-weight: 600;
+}
diff --git a/src/App.jsx b/src/App.jsx
index 45a6426..06fab20 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -1,9 +1,11 @@
-import React, { useState, useEffect, useRef, useCallback } from "react";
+import React, { useState, useEffect, useRef, useCallback, useMemo } from "react";
 import { io } from "socket.io-client";
 import axios from "axios";
 import "./App.css";
 
-const SERVER_URL = "http://localhost:4000";
+const BASE = (import.meta.env.BASE_URL ?? "/").replace(/\/$/, "");
+const API_BASE = `${BASE}/api`;
+const SOCKET_IO_PATH = `${BASE}/socket.io`;
 
 const DEFAULT_HOSTS = [{ url: "", method: "GET" }];
 
@@ -27,6 +29,17 @@ function isToolResult(result) {
   );
 }
 
+function isResultError(result) {
+  if (!result) return false;
+  if (result.type === "error") return true;
+  const body = getToolBody(result);
+  if (body && typeof body.returncode === "number" && body.returncode !== 0) {
+    return true;
+  }
+  if (result.ok === false) return true;
+  return false;
+}
+
 // ─── StatusBadge ──────────────────────────────────────────────────────────────
 function StatusBadge({ status, ok }) {
   if (status === undefined) return <span className="badge pending">PENDING</span>;
@@ -171,6 +184,7 @@ export default function App() {
   const [progress, setProgress] = useState(null); // { done, total }
   const [running, setRunning] = useState(false);
   const [log, setLog] = useState([]);
+  const [collapsedGroups, setCollapsedGroups] = useState(new Set());
 
   const pushLog = useCallback((msg) => {
     setLog((l) => [`[${new Date().toLocaleTimeString()}] ${msg}`, ...l].slice(0, 50));
@@ -178,7 +192,7 @@ export default function App() {
 
   // ── Connect socket once ──────────────────────────────────────────────────
   useEffect(() => {
-    const socket = io(SERVER_URL);
+    const socket = io({ path: SOCKET_IO_PATH });
     socketRef.current = socket;
 
     socket.on("connect", () => {
@@ -274,7 +288,7 @@ export default function App() {
     console.log("sending:", JSON.stringify(payload));
 
     try {
-      await axios.post("http://localhost:4000/api/parallel-fetch", payload);
+      await axios.post(`${API_BASE}/parallel-fetch`, payload);
     } catch (err) {
       pushLog(`POST error: ${err.message}`);
       setRunning(false);
@@ -282,6 +296,22 @@ export default function App() {
   };
 
   const pct = progress ? Math.round((progress.done / progress.total) * 100) : 0;
+  const groupedResults = useMemo(() => {
+    const groups = new Map();
+    results.forEach((result, index) => {
+      if (!result) return;
+      const key = result.serverName || result.host || "Unknown server";
+      const entry = groups.get(key) || { items: [], errors: 0 };
+      entry.items.push({ result, index });
+      if (isResultError(result)) entry.errors += 1;
+      groups.set(key, entry);
+    });
+    return Array.from(groups.entries()).map(([serverName, data]) => ({
+      serverName,
+      items: data.items,
+      errors: data.errors,
+    }));
+  }, [results]);
 
   return (
     <div className="app">
@@ -354,9 +384,49 @@ export default function App() {
           )}
 
           <div className="results-list">
-            {results.map((r, i) => (
-              <ResultCard key={i} result={r} index={i} />
-            ))}
+            {groupedResults.map((group) => {
+              const { serverName, items, errors } = group;
+              const isCollapsed = collapsedGroups.has(serverName);
+              const hasErrors = errors > 0;
+              const groupClass = `server-group ${
+                hasErrors ? "group-err" : "group-ok"
+              }`;
+              return (
+                <div className={groupClass} key={serverName}>
+                  <div
+                    className="server-group-header"
+                    onClick={() =>
+                      setCollapsedGroups((prev) => {
+                        const next = new Set(prev);
+                        if (next.has(serverName)) next.delete(serverName);
+                        else next.add(serverName);
+                        return next;
+                      })
+                    }
+                  >
+                    <div className="server-group-title">
+                      <span className="group-chevron">
+                        {isCollapsed ? "▶" : "▼"}
+                      </span>
+                      <strong>{serverName}</strong>
+                    </div>
+                    <div className="server-group-meta">
+                      <span className="server-errors">
+                        {errors} error{errors === 1 ? "" : "s"}/
+                        {items.length} total
+                      </span>
+                    </div>
+                  </div>
+                  {!isCollapsed && (
+                    <div className="server-group-results">
+                      {items.map(({ result, index }) => (
+                        <ResultCard key={index} result={result} index={index} />
+                      ))}
+                    </div>
+                  )}
+                </div>
+              );
+            })}
           </div>
         </section>
       </main>
diff --git a/vite.config.js b/vite.config.js
index d1203cd..8e3c110 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -4,6 +4,7 @@ import babel from '@rolldown/plugin-babel'
 
 // https://vite.dev/config/
 export default defineConfig({
+  base: '/tool-gui/',
   plugins: [
     react(),
     babel({ presets: [reactCompilerPreset()] })