diff --git a/packages/commons/src/awsSdkUtils.ts b/packages/commons/src/awsSdkUtils.ts
index df922f9e27..5eabe7f396 100644
--- a/packages/commons/src/awsSdkUtils.ts
+++ b/packages/commons/src/awsSdkUtils.ts
@@ -47,9 +47,23 @@ const isSdkClient = (client: unknown): client is SdkClient =>
 const customUserAgentMiddleware = (feature: string) => {
   return <T extends MiddlewareArgsLike>(next: (arg0: T) => Promise<T>) =>
     async (args: T) => {
-      const powertoolsUserAgent = `PT/${feature}/${PT_VERSION} PTEnv/${EXEC_ENV}`;
+      const existingUserAgent = args.request.headers['user-agent'] || '';
+      if (existingUserAgent.includes('PT/NO-OP')) {
+        const featureSpecificUserAgent = existingUserAgent.replace(
+          'PT/NO-OP',
+          `PT/${feature}/${PT_VERSION} PTEnv/${EXEC_ENV}`
+        );
+
+        args.request.headers['user-agent'] = featureSpecificUserAgent;
+        return await next(args);
+      }
+      if (existingUserAgent.includes('PT/')) {
+        return await next(args);
+      }
       args.request.headers['user-agent'] =
-        `${args.request.headers['user-agent']} ${powertoolsUserAgent}`;
+        existingUserAgent === ''
+          ? `PT/${feature}/${PT_VERSION} PTEnv/${EXEC_ENV}`
+          : `${existingUserAgent} PT/${feature}/${PT_VERSION} PTEnv/${EXEC_ENV}`;
 
       return await next(args);
     };
diff --git a/packages/commons/src/index.ts b/packages/commons/src/index.ts
index 591ad8ccff..03b21e2ef7 100644
--- a/packages/commons/src/index.ts
+++ b/packages/commons/src/index.ts
@@ -1,3 +1,8 @@
+import { PT_VERSION } from './version.js';
+if (!process.env.AWS_SDK_UA_APP_ID) {
+  process.env.AWS_SDK_UA_APP_ID = `PT/NO-OP/${PT_VERSION}`;
+}
+export { PT_VERSION } from './version.js';
 export {
   isRecord,
   isString,
@@ -19,4 +24,3 @@ export {
   METRICS_KEY,
   IDEMPOTENCY_KEY,
 } from './middleware/constants.js';
-export { PT_VERSION } from './version.js';
diff --git a/packages/commons/tests/unit/awsSdkUtils.test.ts b/packages/commons/tests/unit/awsSdkUtils.test.ts
index 907409b25d..c8f233e355 100644
--- a/packages/commons/tests/unit/awsSdkUtils.test.ts
+++ b/packages/commons/tests/unit/awsSdkUtils.test.ts
@@ -96,26 +96,49 @@ describe('Helpers: awsSdk', () => {
       expect(middleware).toBeInstanceOf(Function);
     });
 
-    it('adds the Powertools UA to the request headers', async () => {
+    const feature = 'my-feature';
+    const middleware = customUserAgentMiddleware(feature);
+
+    it.each([
+      {
+        case: 'adds the feature-specific UA when none is present',
+        headers: {},
+        expected: `PT/my-feature/${version} PTEnv/NA`,
+      },
+      {
+        case: 'concatenates the ua to existing ones',
+        headers: {
+          'user-agent': 'foo',
+        },
+        expected: `foo PT/my-feature/${version} PTEnv/NA`,
+      },
+      {
+        case: 'replaces no-op UA with the feature-specific one',
+        headers: {
+          'user-agent': 'PT/NO-OP',
+        },
+        expected: `PT/my-feature/${version} PTEnv/NA`,
+      },
+      {
+        case: 'leaves a feature-specific UA intact',
+        headers: {
+          'user-agent': 'PT/other-feature/1.0 PTEnv/NA',
+        },
+        expected: 'PT/other-feature/1.0 PTEnv/NA',
+      },
+    ])('it $case', async ({ headers, expected }) => {
       // Prepare
-      const feature = 'my-feature';
-      const middleware = customUserAgentMiddleware(feature);
-      const next = vi.fn();
       const args = {
         request: {
-          headers: {
-            'user-agent': 'foo',
-          },
+          headers,
         },
       };
 
       // Act
-      await middleware(next)(args);
+      await middleware(vi.fn())(args);
 
       // Assess
-      expect(args.request.headers['user-agent']).toEqual(
-        `foo PT/my-feature/${version} PTEnv/NA`
-      );
+      expect(args.request.headers['user-agent']).toEqual(expected);
     });
   });