diff --git a/src/commands/auth/whoami.ts b/src/commands/auth/whoami.ts
index f662fde..7af04f4 100644
--- a/src/commands/auth/whoami.ts
+++ b/src/commands/auth/whoami.ts
@@ -10,6 +10,10 @@ export const authWhoamiCommand: Command = {
   async execute(config: Config): Promise<void> {
     const api = new PolylaneAPI(config);
     const user = await api.authWhoami();
+    if (config.quiet && config.output === 'text') {
+      process.stdout.write(`Signed in as ${user.email || user.id}\n`);
+      return;
+    }
     formatOutput(config, user);
   },
 };
diff --git a/test/auth-whoami.test.ts b/test/auth-whoami.test.ts
new file mode 100644
index 0000000..266543f
--- /dev/null
+++ b/test/auth-whoami.test.ts
@@ -0,0 +1,64 @@
+import { after, before, beforeEach, describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { authWhoamiCommand } from '../src/commands/auth/whoami';
+import { mockConfig } from './helpers/config';
+
+const user = {
+  id: 'user_123',
+  email: 'dev@example.test',
+  username: 'dev',
+  scope: 'read write',
+  _html_url: 'https://console.example.test/users/user_123',
+};
+
+describe('auth whoami', () => {
+  const originalFetch = globalThis.fetch;
+  const originalWrite = process.stdout.write;
+  let stdout = '';
+
+  before(() => {
+    process.stdout.write = ((chunk: string | Uint8Array): boolean => {
+      stdout += String(chunk);
+      return true;
+    }) as typeof process.stdout.write;
+  });
+
+  beforeEach(() => {
+    delete process.env.POLYLANE_API_KEY;
+    stdout = '';
+    globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
+      assert.equal(String(input), 'https://api.example.test/v1/auth/whoami');
+      assert.equal(new Headers(init?.headers).get('x-api-key'), 'test-key');
+      return Response.json({ success: true, error: null, result: user });
+    }) as typeof fetch;
+  });
+
+  after(() => {
+    globalThis.fetch = originalFetch;
+    process.stdout.write = originalWrite;
+  });
+
+  it('keeps the full identity in ordinary text output', async () => {
+    await authWhoamiCommand.execute(mockConfig({ apiKey: 'test-key', apiKeySource: 'flag', output: 'text' }), {}, {});
+    assert.match(stdout, /id\s+user_123/);
+    assert.match(stdout, /email\s+dev@example\.test/);
+    assert.match(stdout, /scope\s+read write/);
+    assert.match(stdout, /Console:  https:\/\/console\.example\.test\/users\/user_123/);
+  });
+
+  it('prints only the email on one line in quiet text output', async () => {
+    await authWhoamiCommand.execute(mockConfig({ apiKey: 'test-key', apiKeySource: 'flag', output: 'text', quiet: true }), {}, {});
+    assert.equal(stdout, 'Signed in as dev@example.test\n');
+  });
+
+  it('preserves structured JSON even when quiet is set', async () => {
+    await authWhoamiCommand.execute(mockConfig({ apiKey: 'test-key', apiKeySource: 'flag', output: 'json', quiet: true }), {}, {});
+    assert.deepEqual(JSON.parse(stdout), user);
+  });
+
+  it('uses the user id when an email is unavailable', async () => {
+    globalThis.fetch = (async () => Response.json({ success: true, error: null, result: { id: 'user_123', email: '' } })) as typeof fetch;
+    await authWhoamiCommand.execute(mockConfig({ apiKey: 'test-key', apiKeySource: 'flag', output: 'text', quiet: true }), {}, {});
+    assert.equal(stdout, 'Signed in as user_123\n');
+  });
+});