diff --git a/src/fosslight_source/_exclude.py b/src/fosslight_source/_exclude.py
index 830382f..cb05fcf 100644
--- a/src/fosslight_source/_exclude.py
+++ b/src/fosslight_source/_exclude.py
@@ -1,10 +1,14 @@
 # Copyright (c) 2026 LG Electronics Inc.
 # SPDX-License-Identifier: Apache-2.0
 
-"""Source-scanner filename excludes (not applied to dependency discovery)."""
+"""Source-scanner exclusion helpers (not applied to dependency discovery)."""
+
+import os
 
 from fosslight_util.exclude import is_excluded_filename
 
+DEFAULT_SKIP_SMALL_FILE_SIZE = 150
+
 # Build/package config noise for license scans.
 EXCLUDE_FILENAME_SOURCE = frozenset({
     "changelog", "config.guess", "config.sub", "changes", "ltmain.sh",
@@ -19,3 +23,11 @@
 
 def is_excluded_source_filename(file_path: str) -> bool:
     return is_excluded_filename(file_path, EXCLUDE_FILENAME_SOURCE)
+
+
+def is_small_file(file_path: str) -> bool:
+    """Return whether a file is at or below the KB/SCANOSS size threshold."""
+    try:
+        return os.path.getsize(file_path) <= DEFAULT_SKIP_SMALL_FILE_SIZE
+    except OSError:
+        return False
diff --git a/src/fosslight_source/_help.py b/src/fosslight_source/_help.py
index cd8844b..0051bf7 100644
--- a/src/fosslight_source/_help.py
+++ b/src/fosslight_source/_help.py
@@ -47,7 +47,6 @@
     --kb_token <token>     KB bearer token (priority: parameter > KB_TOKEN env)
                            HTTPS uses the OS certificate store. Set KB_SSL_VERIFY=false
                            only if certificate verification must be skipped.
-
     💡 Examples
     ────────────────────────────────────────────────────────────────────
     # Scan current directory
diff --git a/src/fosslight_source/_scan_item.py b/src/fosslight_source/_scan_item.py
index c0dce53..33b42f7 100644
--- a/src/fosslight_source/_scan_item.py
+++ b/src/fosslight_source/_scan_item.py
@@ -63,7 +63,7 @@ def __init__(self, value: str) -> None:
         self.checksum = get_checksum_sha1(value)
         self.kb_origin_url = ""  # URL from OSS KB
         self.kb_evidence = ""   # Evidence from KB API (exact_match or code snippet)
-        self._cached_kb_md5 = ""  # MD5 precomputed for KB lookup (set by _collect_kb_file_hashes)
+        self._cached_kb_md5: str | None = None  # None: not checked; empty: checked but no KB hash
 
     def __del__(self) -> None:
         pass
@@ -192,8 +192,9 @@ def set_oss_item(
             item = OssItem(self.oss_name, self.oss_version, self.licenses)
             if kb_origin_urls and not self.is_license_text:
                 md5_hash = self._cached_kb_md5
-                if not md5_hash:
+                if md5_hash is None:
                     md5_hash, _wfp = self._get_hash(path_to_scan)
+                    self._cached_kb_md5 = md5_hash
                 if md5_hash:
                     origin_url = kb_origin_urls.get(md5_hash, "")
                     if origin_url:
diff --git a/src/fosslight_source/cli.py b/src/fosslight_source/cli.py
index 3d1d778..00b64a6 100755
--- a/src/fosslight_source/cli.py
+++ b/src/fosslight_source/cli.py
@@ -22,7 +22,7 @@
 from fosslight_util.parsing_yaml import SUPPORT_OSS_INFO_FILES
 from .run_scancode import run_scan
 from fosslight_util.exclude import get_excluded_paths
-from ._exclude import EXCLUDE_FILENAME_SOURCE, is_excluded_source_filename
+from ._exclude import EXCLUDE_FILENAME_SOURCE, is_excluded_source_filename, is_small_file
 from .run_scanoss import run_scanoss_py
 from .run_scanoss import get_scanoss_extra_info
 import yaml
@@ -93,7 +93,6 @@ def main() -> None:
     parser.add_argument('--ui', action='store_true', required=False)
 
     args = parser.parse_args()
-
     if args.help:
         print_help_msg_source_scanner()
     if args.version:
@@ -362,9 +361,15 @@ def _collect_kb_file_hashes(
     extra_candidates: list[tuple[SourceItem, str]] = []
 
     for item in scancode_result:
-        if item.is_license_text or is_notice_file(item.source_name_or_path):
+        if item.is_license_text or item.download_location or is_notice_file(item.source_name_or_path):
+            item._cached_kb_md5 = ""
             continue
-        if item.download_location:
+        item_path = item.source_name_or_path
+        if not os.path.isabs(item_path):
+            item_path = os.path.join(path_to_scan, item_path)
+        if is_small_file(item_path):
+            # An empty cached hash means this item is checked and not KB-eligible.
+            item._cached_kb_md5 = ""
             continue
         md5_hash, _wfp = item._get_hash(path_to_scan)
         if md5_hash:
@@ -384,6 +389,8 @@ def _collect_kb_file_hashes(
         if (rel_path in scancode_paths or rel_path in excluded_files
                 or is_excluded_source_filename(rel_path) or is_notice_file(file_path)):
             continue
+        if is_small_file(file_path):
+            continue
         extra_item = SourceItem(rel_path)
         md5_hash, _wfp = extra_item._get_hash(path_to_scan)
         if md5_hash:
diff --git a/src/fosslight_source/run_scanoss.py b/src/fosslight_source/run_scanoss.py
index 51b0b99..4217286 100755
--- a/src/fosslight_source/run_scanoss.py
+++ b/src/fosslight_source/run_scanoss.py
@@ -10,6 +10,7 @@
 import json
 from typing import Tuple
 import fosslight_util.constant as constant
+from ._exclude import DEFAULT_SKIP_SMALL_FILE_SIZE
 from ._parsing_scanoss_file import parsing_scan_result  # scanoss
 from ._parsing_scanoss_file import parsing_extra_info  # scanoss
 from scanoss.scanner import Scanner, ScanType
@@ -66,6 +67,7 @@ def run_scanoss_py(path_to_scan: str, output_path: str = "", format: list = [],
         scanner = Scanner(
             ignore_cert_errors=True,
             skip_folders=list(path_to_exclude) if path_to_exclude else [],
+            skip_size=DEFAULT_SKIP_SMALL_FILE_SIZE + 1,
             scan_output=output_json_file,
             scan_options=ScanType.SCAN_SNIPPETS.value,
             nb_threads=num_threads if num_threads > 0 else 10,