diff --git a/backend/packages/harness/deerflow/sandbox/search.py b/backend/packages/harness/deerflow/sandbox/search.py
index a85938870..a5cf1314e 100644
--- a/backend/packages/harness/deerflow/sandbox/search.py
+++ b/backend/packages/harness/deerflow/sandbox/search.py
@@ -67,11 +67,22 @@ class GrepMatch:
     line: str
 
 
+# ``should_ignore_name`` runs once per directory entry during glob/grep tree
+# walks, so we avoid ~50 ``fnmatch`` calls per name. Most ignore patterns are
+# literal names (O(1) set lookup after normcase); the few glob patterns are
+# pre-translated into a single combined regex. ``os.path.normcase`` keeps the
+# same case behavior ``fnmatch`` applies (case-sensitive on POSIX, folded on
+# Windows).
+_EXACT_IGNORE_NAMES = frozenset(os.path.normcase(p) for p in IGNORE_PATTERNS if not any(c in p for c in "*?["))
+_GLOB_IGNORE_PATTERNS = [p for p in IGNORE_PATTERNS if any(c in p for c in "*?[")]
+_GLOB_IGNORE_RE = re.compile("|".join(fnmatch.translate(os.path.normcase(p)) for p in _GLOB_IGNORE_PATTERNS)) if _GLOB_IGNORE_PATTERNS else None
+
+
 def should_ignore_name(name: str) -> bool:
-    for pattern in IGNORE_PATTERNS:
-        if fnmatch.fnmatch(name, pattern):
-            return True
-    return False
+    normalized = os.path.normcase(name)
+    if normalized in _EXACT_IGNORE_NAMES:
+        return True
+    return _GLOB_IGNORE_RE is not None and _GLOB_IGNORE_RE.match(normalized) is not None
 
 
 def should_ignore_path(path: str) -> bool:
diff --git a/backend/tests/test_should_ignore_name.py b/backend/tests/test_should_ignore_name.py
new file mode 100644
index 000000000..4fddae874
--- /dev/null
+++ b/backend/tests/test_should_ignore_name.py
@@ -0,0 +1,72 @@
+"""should_ignore_name must stay behavior-identical to the original per-pattern
+fnmatch loop while doing O(1) set lookup + one combined glob regex instead of
+~50 fnmatch calls per directory entry.
+"""
+
+from __future__ import annotations
+
+import fnmatch
+
+from deerflow.sandbox.search import IGNORE_PATTERNS, should_ignore_name, should_ignore_path
+
+
+def _reference(name: str) -> bool:
+    """Original implementation, kept here as the equivalence oracle."""
+    return any(fnmatch.fnmatch(name, pattern) for pattern in IGNORE_PATTERNS)
+
+
+_SAMPLES = [
+    # exact-name ignores
+    ".git",
+    "node_modules",
+    "__pycache__",
+    ".venv",
+    "env",
+    "logs",
+    "coverage",
+    ".pytest_cache",
+    ".DS_Store",
+    "Thumbs.db",
+    "desktop.ini",
+    # glob ignores
+    "thing.egg-info",
+    "x.swp",
+    "y.swo",
+    "z.log",
+    "a.tmp",
+    "b.temp",
+    "c.bak",
+    "d.cache",
+    "core~",
+    "shortcut.lnk",
+    # kept (must NOT be ignored)
+    "foo.py",
+    "README.md",
+    "src",
+    "myenv",
+    "node_modules_x",
+    "x.git",
+    "log",
+    "main.c",
+]
+
+
+def test_matches_reference_for_all_samples():
+    for name in _SAMPLES:
+        assert should_ignore_name(name) == _reference(name), name
+
+
+def test_known_ignored_names():
+    for name in [".git", "node_modules", "__pycache__", "x.swp", "z.log", "core~", "thing.egg-info"]:
+        assert should_ignore_name(name) is True
+
+
+def test_known_kept_names():
+    for name in ["foo.py", "README.md", "src", "myenv", "node_modules_x", "x.git"]:
+        assert should_ignore_name(name) is False
+
+
+def test_should_ignore_path_segments():
+    assert should_ignore_path("a/node_modules/b") is True
+    assert should_ignore_path("proj/.git/config") is True
+    assert should_ignore_path("a/b/c.py") is False