diff --git a/src/lib/config.ts b/src/lib/config.ts
index 86abc08e..60d7f867 100644
--- a/src/lib/config.ts
+++ b/src/lib/config.ts
@@ -459,9 +459,29 @@ export async function renameProfileAsync(
   oldName: string,
   newName: string,
 ): Promise<void> {
+  if (oldName === newName) {
+    return;
+  }
+
+  const validationError = validateProfileName(newName);
+  if (validationError) {
+    throw new Error(validationError);
+  }
+
   const creds = readCredentials();
+  if (!creds) {
+    throw new Error('No credentials file found. Run: resend login');
+  }
+  if (!creds.profiles[oldName]) {
+    throw new Error(
+      `Profile "${oldName}" not found. Available profiles: ${Object.keys(creds.profiles).join(', ')}`,
+    );
+  }
+  if (creds.profiles[newName]) {
+    throw new Error(`Profile "${newName}" already exists.`);
+  }
 
-  if (creds?.storage === 'secure_storage') {
+  if (creds.storage === 'secure_storage') {
     const backend = await getCredentialBackend();
     if (backend.isSecure) {
       const key = await backend.get(SERVICE_NAME, oldName);
@@ -472,5 +492,10 @@ export async function renameProfileAsync(
     }
   }
 
-  renameProfile(oldName, newName);
+  creds.profiles[newName] = creds.profiles[oldName];
+  delete creds.profiles[oldName];
+  if (creds.active_profile === oldName) {
+    creds.active_profile = newName;
+  }
+  writeCredentials(creds);
 }
diff --git a/tests/lib/config-async.test.ts b/tests/lib/config-async.test.ts
index a5d7c364..9d9063fb 100644
--- a/tests/lib/config-async.test.ts
+++ b/tests/lib/config-async.test.ts
@@ -485,4 +485,159 @@ describe('renameProfileAsync', () => {
     expect(creds?.profiles['new-name']).toEqual({ api_key: 're_file_key' });
     expect(creds?.profiles['old-name']).toBeUndefined();
   });
+
+  test('no-op rename does not touch secure backend', async () => {
+    const configDir = join(tmpDir, 'resend');
+    mkdirSync(configDir, { recursive: true });
+    writeFileSync(
+      join(configDir, 'credentials.json'),
+      JSON.stringify({
+        active_profile: 'same-name',
+        storage: 'secure_storage',
+        profiles: { 'same-name': {} },
+      }),
+    );
+
+    const mockBackend = {
+      get: vi.fn(),
+      set: vi.fn(),
+      delete: vi.fn(),
+      isAvailable: vi.fn().mockResolvedValue(true),
+      name: 'mock-backend',
+      isSecure: true,
+    };
+
+    vi.resetModules();
+    vi.doMock('../../src/lib/credential-store', () => ({
+      getCredentialBackend: vi.fn().mockResolvedValue(mockBackend),
+      SERVICE_NAME: 'resend-cli',
+      resetCredentialBackend: vi.fn(),
+    }));
+
+    const { renameProfileAsync, readCredentials } = await import(
+      '../../src/lib/config'
+    );
+    await renameProfileAsync('same-name', 'same-name');
+    expect(mockBackend.get).not.toHaveBeenCalled();
+    expect(mockBackend.set).not.toHaveBeenCalled();
+    expect(mockBackend.delete).not.toHaveBeenCalled();
+    const creds = readCredentials();
+    expect(creds?.profiles['same-name']).toBeDefined();
+  });
+
+  test('rejects rename to existing profile without touching secure backend', async () => {
+    const configDir = join(tmpDir, 'resend');
+    mkdirSync(configDir, { recursive: true });
+    writeFileSync(
+      join(configDir, 'credentials.json'),
+      JSON.stringify({
+        active_profile: 'alpha',
+        storage: 'secure_storage',
+        profiles: { alpha: {}, beta: {} },
+      }),
+    );
+
+    const mockBackend = {
+      get: vi.fn(),
+      set: vi.fn(),
+      delete: vi.fn(),
+      isAvailable: vi.fn().mockResolvedValue(true),
+      name: 'mock-backend',
+      isSecure: true,
+    };
+
+    vi.resetModules();
+    vi.doMock('../../src/lib/credential-store', () => ({
+      getCredentialBackend: vi.fn().mockResolvedValue(mockBackend),
+      SERVICE_NAME: 'resend-cli',
+      resetCredentialBackend: vi.fn(),
+    }));
+
+    const { renameProfileAsync, readCredentials } = await import(
+      '../../src/lib/config'
+    );
+    await expect(renameProfileAsync('alpha', 'beta')).rejects.toThrow(
+      'already exists',
+    );
+    expect(mockBackend.get).not.toHaveBeenCalled();
+    expect(mockBackend.set).not.toHaveBeenCalled();
+    expect(mockBackend.delete).not.toHaveBeenCalled();
+    const creds = readCredentials();
+    expect(creds?.profiles.alpha).toBeDefined();
+    expect(creds?.profiles.beta).toBeDefined();
+  });
+
+  test('rejects invalid new name without touching secure backend', async () => {
+    const configDir = join(tmpDir, 'resend');
+    mkdirSync(configDir, { recursive: true });
+    writeFileSync(
+      join(configDir, 'credentials.json'),
+      JSON.stringify({
+        active_profile: 'valid',
+        storage: 'secure_storage',
+        profiles: { valid: {} },
+      }),
+    );
+
+    const mockBackend = {
+      get: vi.fn(),
+      set: vi.fn(),
+      delete: vi.fn(),
+      isAvailable: vi.fn().mockResolvedValue(true),
+      name: 'mock-backend',
+      isSecure: true,
+    };
+
+    vi.resetModules();
+    vi.doMock('../../src/lib/credential-store', () => ({
+      getCredentialBackend: vi.fn().mockResolvedValue(mockBackend),
+      SERVICE_NAME: 'resend-cli',
+      resetCredentialBackend: vi.fn(),
+    }));
+
+    const { renameProfileAsync } = await import('../../src/lib/config');
+    await expect(renameProfileAsync('valid', 'has spaces')).rejects.toThrow(
+      'letters',
+    );
+    expect(mockBackend.get).not.toHaveBeenCalled();
+    expect(mockBackend.set).not.toHaveBeenCalled();
+    expect(mockBackend.delete).not.toHaveBeenCalled();
+  });
+
+  test('rejects rename of non-existent profile without touching secure backend', async () => {
+    const configDir = join(tmpDir, 'resend');
+    mkdirSync(configDir, { recursive: true });
+    writeFileSync(
+      join(configDir, 'credentials.json'),
+      JSON.stringify({
+        active_profile: 'exists',
+        storage: 'secure_storage',
+        profiles: { exists: {} },
+      }),
+    );
+
+    const mockBackend = {
+      get: vi.fn(),
+      set: vi.fn(),
+      delete: vi.fn(),
+      isAvailable: vi.fn().mockResolvedValue(true),
+      name: 'mock-backend',
+      isSecure: true,
+    };
+
+    vi.resetModules();
+    vi.doMock('../../src/lib/credential-store', () => ({
+      getCredentialBackend: vi.fn().mockResolvedValue(mockBackend),
+      SERVICE_NAME: 'resend-cli',
+      resetCredentialBackend: vi.fn(),
+    }));
+
+    const { renameProfileAsync } = await import('../../src/lib/config');
+    await expect(renameProfileAsync('nope', 'new-name')).rejects.toThrow(
+      'not found',
+    );
+    expect(mockBackend.get).not.toHaveBeenCalled();
+    expect(mockBackend.set).not.toHaveBeenCalled();
+    expect(mockBackend.delete).not.toHaveBeenCalled();
+  });
 });