diff --git a/addon/ScopeDetection.py b/addon/ScopeDetection.py
new file mode 100644
index 0000000..a955aeb
--- /dev/null
+++ b/addon/ScopeDetection.py
@@ -0,0 +1,53 @@
+import lib.target as target
+from lib.report import save_report
+
+class ScopeDetection:
+    def get_scope_from_query(self, query: str) -> str | None:
+        if not query:
+            return None
+        import urllib.parse
+        parsed = urllib.parse.parse_qs(query)
+        scope_values = parsed.get("scope", [])
+        if scope_values:
+            return scope_values[0]
+        return None
+
+    async def check_scope(self, flow):
+        req = flow.request
+        res = flow.response
+
+        # req.query가 MultiDictView일 수 있으므로 문자열로 변환
+        if hasattr(req.query, "urlencode"):
+            query = req.query.urlencode()
+        else:
+            query = str(req.query) if req.query else ""
+
+        location = res.headers.get("location", "")
+
+        query_scope = self.get_scope_from_query(query)
+        location_scope = self.get_scope_from_query(location)
+
+        result = []
+        if query_scope in ["all", "*"]:
+            result.append(f"Scope value issue detected in request: {query_scope}")
+        if location_scope in ["all", "*"]:
+            result.append(f"Scope value issue detected in response location: {location_scope}")
+
+        return result if result else 0
+
+    async def test(self, flow):
+        req = flow.request
+        method = req.method
+        url = req.pretty_url
+
+        result = await self.check_scope(flow)
+
+        if result != 0:
+            report_data = [{
+                'target': target.load(),
+                'status': "WARNING",
+                'title': "OAuth scope value issue",
+                'description': f"{method} {url}: {', '.join(result)}",
+                'uri': url
+            }]
+            save_report(report_data)
diff --git a/addon/init.py b/addon/init.py
index 25bebeb..6b93810 100644
--- a/addon/init.py
+++ b/addon/init.py
@@ -1,6 +1,7 @@
 from mitmproxy import http
 import asyncio
 from pkce_check import PKCEDowngradeChecker
+from ScopeDetection import ScopeDetection
 
 class PKCEAddon:
     def __init__(self):
@@ -13,4 +14,25 @@ class PKCEAddon:
         except Exception as e:
             print(f"[ERROR] Addon failed: {e}")
 
-addons = [PKCEAddon()]
+class ScopeAddon:
+    def __init__(self):
+        self.checker = ScopeDetection()
+        self._flow_map = {}  # 요청 정보를 저장
+
+    async def request(self, flow: http.HTTPFlow):
+        self._flow_map[flow.id] = {
+            "method": flow.request.method,
+            "url": flow.request.pretty_url,
+            "query": flow.request.query,
+        }
+
+    async def response(self, flow: http.HTTPFlow):
+        try:
+            await self.checker.test(flow)
+        except Exception as e:
+            print(f"[ERROR] ScopeDetection failed: {e}")
+
+
+addons = [PKCEAddon(),
+          ScopeAddon()
+]