diff --git a/static/js/chat.js b/static/js/chat.js
index 60149d005..7ecefdb7d 100644
--- a/static/js/chat.js
+++ b/static/js/chat.js
@@ -1082,7 +1082,7 @@ import { wireArrowUpRecall, getLastUserMessageFromChatHistory } from './composer
       let _lastToolName = '';
       const _searchIcon = '<svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" style="vertical-align:-2px;margin-right:4px"><circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/></svg>';
       const _toolLabels = {
-        'web_search': _searchIcon + 'Searching',
+        'web_search': 'Searching',
         'bash': 'Running',
         'python': 'Running',
         'create_document': 'Writing',
@@ -1102,6 +1102,9 @@ import { wireArrowUpRecall, getLastUserMessageFromChatHistory } from './composer
         'list_models': 'Browsing',
         'ui_control': 'Adjusting',
       };
+      const _toolIcons = {
+        'web_search': _searchIcon,
+      };
       function _thinkingLabel() {
         if (!_lastToolName) {
           return 'Thinking';
@@ -2049,10 +2052,11 @@ import { wireArrowUpRecall, getLastUserMessageFromChatHistory } from './composer
                 }
                 threadWrap.classList.add('streaming');
                 const toolLabel = _toolLabels[json.tool.toLowerCase()] || json.tool;
+                const toolIcon = _toolIcons[json.tool.toLowerCase()] || '\u25B6';
                 const node = document.createElement('div')
                 node.className = 'agent-thread-node running';
                 const cmdHtml = cmd ? `<pre class="agent-thread-cmd">${esc(cmd)}</pre>` : '';
-                node.innerHTML = `<div class="agent-thread-dot"></div><div class="agent-thread-header"><span class="agent-thread-icon">\u25B6</span><span class="agent-thread-tool">${esc(toolLabel)}</span><span class="agent-thread-wave">▁▂▃</span></div><div class="agent-thread-content">${cmdHtml}</div>`;
+                node.innerHTML = `<div class="agent-thread-dot"></div><div class="agent-thread-header"><span class="agent-thread-icon">${toolIcon}</span><span class="agent-thread-tool">${esc(toolLabel)}</span><span class="agent-thread-wave">▁▂▃</span></div><div class="agent-thread-content">${cmdHtml}</div>`;
                 // Expand/collapse via delegated click handler (init at module bottom).
                 threadWrap.appendChild(node);
                 currentToolBubble = node;
diff --git a/tests/test_web_search_tool_icon_js.py b/tests/test_web_search_tool_icon_js.py
new file mode 100644
index 000000000..6e855df40
--- /dev/null
+++ b/tests/test_web_search_tool_icon_js.py
@@ -0,0 +1,119 @@
+"""Pin the web_search tool-icon rendering in the agent thread (PR #??).
+
+Verifies:
+- web_search renders an <svg> icon instead of raw markup
+- Other tools get the default ▶ icon
+- Hostile tool names are HTML-escaped in the label
+
+Pure JS via node --input-type=module (same approach as
+test_composer_arrow_up_recall_js.py). Skips when node is not installed.
+"""
+
+import json
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+_REPO = Path(__file__).resolve().parent.parent
+_HAS_NODE = shutil.which("node") is not None
+
+_CHECK_JS = r"""
+function esc(s) {
+  const map = { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' };
+  return (s || '').replace(/[&<>"']/g, (m) => map[m]);
+}
+
+const _searchIcon = '<svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" style="vertical-align:-2px;margin-right:4px"><circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/></svg>';
+
+const _toolLabels = {
+  web_search: 'Searching',
+  bash: 'Running',
+};
+
+const _toolIcons = {
+  web_search: _searchIcon,
+};
+
+function renderIcon(toolName) {
+  return _toolIcons[toolName.toLowerCase()] || '\u25B6';
+}
+
+function renderLabel(toolName) {
+  return _toolLabels[toolName.toLowerCase()] || toolName;
+}
+
+function renderThreadHTML(toolName, cmd) {
+  const label = renderLabel(toolName);
+  const icon = renderIcon(toolName);
+  const cmdHtml = cmd ? `<pre class="agent-thread-cmd">${esc(cmd)}</pre>` : '';
+  return `<div class="agent-thread-dot"></div><div class="agent-thread-header"><span class="agent-thread-icon">${icon}</span><span class="agent-thread-tool">${esc(label)}</span><span class="agent-thread-wave">\u2581\u2582\u2583</span></div><div class="agent-thread-content">${cmdHtml}</div>`;
+}
+
+const cases = CASES_JSON;
+const results = cases.map(c => {
+  const html = renderThreadHTML(c.tool, c.cmd || '');
+  return { tool: c.tool, html };
+});
+console.log(JSON.stringify(results));
+"""
+
+
+def _run(cases: list) -> list:
+    js = _CHECK_JS.replace("CASES_JSON", json.dumps(cases))
+    proc = subprocess.run(
+        ["node", "--input-type=module"],
+        input=js,
+        capture_output=True,
+        text=True,
+        encoding="utf-8",
+        cwd=str(_REPO),
+        timeout=30,
+    )
+    assert proc.returncode == 0, proc.stderr
+    return json.loads(proc.stdout.strip())
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_web_search_icon_contains_svg():
+    out = _run([{"tool": "web_search"}])[0]
+    assert "<svg" in out["html"], "Expected <svg> in agent-thread-icon for web_search"
+    assert "Searching" in out["html"], "Expected 'Searching' label for web_search"
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_default_tool_icon_is_triangle():
+    out = _run([{"tool": "bash"}])[0]
+    assert "▶" in out["html"], "Expected ▶ icon for tools without custom icon"
+    assert "<svg" not in out["html"], "Expected no <svg> for bash"
+    assert "Running" in out["html"], "Expected 'Running' label for bash"
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_unknown_tool_falls_back_to_name():
+    out = _run([{"tool": "my_custom_tool"}])[0]
+    assert "▶" in out["html"], "Expected ▶ for unknown tool"
+    assert "my_custom_tool" in out["html"], "Expected tool name as label"
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_hostile_tool_name_is_escaped():
+    out = _run([{"tool": '<img src=x onerror="alert(1)">'}])[0]
+    assert "&lt;img" in out["html"], "Expected < to be HTML-escaped"
+    assert "&gt;" in out["html"], "Expected > to be HTML-escaped"
+    assert "<img" not in out["html"], "Raw <img> must not appear"
+    assert "onerror" not in out["html"] or "&quot;" in out["html"], "onerror must not be executable"
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_unknown_tool_case_insensitive_matches_icons():
+    out = _run([{"tool": "WEB_SEARCH"}, {"tool": "Web_Search"}])
+    for r in out:
+        assert "<svg" in r["html"], f"Expected SVG for case-variant '{r['tool']}'"
+
+
+@pytest.mark.skipif(not _HAS_NODE, reason="node binary not on PATH")
+def test_command_is_escaped():
+    out = _run([{"tool": "bash", "cmd": "echo $HOME && ls"}])[0]
+    assert "echo $HOME" in out["html"], "Expected command text in output"