diff --git a/release-please-config.json b/release-please-config.json
index f473b24..fc1a9dd 100644
--- a/release-please-config.json
+++ b/release-please-config.json
@@ -8,7 +8,8 @@
             "bump-patch-for-minor-pre-major": false,
             "draft": false,
             "prerelease": false,
-            "include-component-in-tag": false
+            "include-component-in-tag": false,
+            "extra-files": ["sdk/version.ts"]
         }
     },
     "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
diff --git a/sdk/utils.ts b/sdk/utils.ts
index 016e274..660249e 100644
--- a/sdk/utils.ts
+++ b/sdk/utils.ts
@@ -1,11 +1,11 @@
 import { createHash } from 'crypto';
 import { Fetch, FlagsmithTraitValue, TraitConfig } from './types.js';
 import { Dispatcher } from 'undici-types';
+import { SDK_VERSION } from './version.js';
 
 type Traits = { [key: string]: TraitConfig | FlagsmithTraitValue };
 
 const FLAGSMITH_USER_AGENT = 'flagsmith-nodejs-sdk';
-const FLAGSMITH_UNKNOWN_VERSION = 'unknown';
 
 export function isTraitConfig(
     traitValue: TraitConfig | FlagsmithTraitValue
@@ -130,11 +130,5 @@ export class Deferred<T> {
 }
 
 export function getUserAgent(): string {
-    try {
-        const packageJson = require('../package.json');
-        const version = packageJson?.version;
-        return version ? `${FLAGSMITH_USER_AGENT}/${version}` : FLAGSMITH_UNKNOWN_VERSION;
-    } catch {
-        return FLAGSMITH_UNKNOWN_VERSION;
-    }
+    return `${FLAGSMITH_USER_AGENT}/${SDK_VERSION}`;
 }
diff --git a/sdk/version.ts b/sdk/version.ts
new file mode 100644
index 0000000..8e9cf2d
--- /dev/null
+++ b/sdk/version.ts
@@ -0,0 +1 @@
+export const SDK_VERSION = '9.0.1'; // x-release-please-version
diff --git a/tests/sdk/flagsmith.test.ts b/tests/sdk/flagsmith.test.ts
index 766367c..acaf939 100644
--- a/tests/sdk/flagsmith.test.ts
+++ b/tests/sdk/flagsmith.test.ts
@@ -512,8 +512,7 @@ test('getIdentityFlags succeeds if initial fetch failed then succeeded', async (
     expect(flags2.isFeatureEnabled('some_feature')).toBe(true);
 });
 
-// Skip in ESM build: require() path resolution differs
-test.skipIf(isEsmBuild)('get_user_agent_extracts_version_from_package_json', async () => {
+test('get_user_agent_matches_package_version', async () => {
     const userAgent = getUserAgent();
     const packageJson = require('../../package.json');