diff --git a/background/contribution-oauth.js b/background/contribution-oauth.js
index 7dc5608..e95cbc3 100644
--- a/background/contribution-oauth.js
+++ b/background/contribution-oauth.js
@@ -599,6 +599,7 @@
         body: {
           nickname: buildNickname(currentState, options.nickname),
           qq: buildContributionQq(currentState, options.qq),
+          email: normalizeString(currentState.email),
           source: 'cpa',
           channel: 'codex-extension',
         },
diff --git a/tests/background-contribution-mode.test.js b/tests/background-contribution-mode.test.js
index b3d6901..67202c7 100644
--- a/tests/background-contribution-mode.test.js
+++ b/tests/background-contribution-mode.test.js
@@ -423,6 +423,7 @@ test('contribution oauth manager starts session, opens auth url, submits callbac
   assert.match(fetchCalls[0].url, /\/start$/);
   assert.match(String(fetchCalls[0].options.body || ''), /"nickname":""/);
   assert.match(String(fetchCalls[0].options.body || ''), /"qq":""/);
+  assert.match(String(fetchCalls[0].options.body || ''), /"email":"user@example\.com"/);
   assert.match(fetchCalls[1].url, /\/status\?/);
 
   const callbackState = await manager.handleCapturedCallback(