diff --git a/src/usage-api.ts b/src/usage-api.ts
index c4f9b72..347c78b 100644
--- a/src/usage-api.ts
+++ b/src/usage-api.ts
@@ -48,6 +48,7 @@ const CACHE_FAILURE_TTL_MS = 15_000; // 15 seconds for failed requests
 const KEYCHAIN_TIMEOUT_MS = 3000;
 const KEYCHAIN_BACKOFF_MS = 60_000; // Backoff on keychain failures to avoid re-prompting
 const USAGE_API_TIMEOUT_MS_DEFAULT = 15_000;
+export const USAGE_API_USER_AGENT = 'claude-code/2.1';
 
 interface CacheFile {
   data: UsageData;
@@ -662,7 +663,7 @@ function fetchUsageApi(accessToken: string): Promise<UsageApiResult> {
       headers: {
         'Authorization': `Bearer ${accessToken}`,
         'anthropic-beta': 'oauth-2025-04-20',
-        'User-Agent': 'claude-hud/1.0',
+        'User-Agent': USAGE_API_USER_AGENT,
       },
       timeout: timeoutMs,
       agent: proxyUrl ? createProxyTunnelAgent(proxyUrl) : undefined,
diff --git a/tests/usage-api.test.js b/tests/usage-api.test.js
index bde6232..1c6c46b 100644
--- a/tests/usage-api.test.js
+++ b/tests/usage-api.test.js
@@ -9,6 +9,7 @@ import {
   getUsageApiTimeoutMs,
   isNoProxy,
   getProxyUrl,
+  USAGE_API_USER_AGENT,
 } from '../dist/usage-api.js';
 import { mkdtemp, rm, mkdir, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
@@ -505,6 +506,10 @@ describe('getUsage', () => {
   });
 });
 
+test('usage API user agent matches the working Claude Code identifier', () => {
+  assert.equal(USAGE_API_USER_AGENT, 'claude-code/2.1');
+});
+
 describe('getKeychainServiceName', () => {
   test('uses legacy default service name for default config directory', () => {
     const homeDir = '/tmp/claude-hud-home-default';