1. About the app
Cangtian Mail Assistant ("the app") is a command-line utility that organises Gmail messages by applying labels to them, according to a fixed set of classification rules. It is developed and operated by a single individual for their own Gmail account.
The app is not a commercial product. It is not distributed, licensed, sold, or otherwise made available to any other person, and no service is provided to the public.
2. Acceptance of these terms
By installing, running, or otherwise using the app, the operator accepts these terms. If these terms are not acceptable, the app should not be used, and the operator should revoke its access to the relevant Google Account.
3. Permitted use
The app is provided for personal, non-commercial use limited to the following:
- organising messages in the operator's own Gmail account;
- reading the app's source code and documentation for the operator's own reference;
- modifying the app for the operator's own private, non-commercial purposes.
4. Prohibited use
The app must not be used to:
- access any Gmail account other than one the operator owns and is authorised to access;
- violate Google's terms of service, the Google API Services User Data Policy, or any applicable law or regulation;
- send unsolicited messages, conduct bulk mail operations, or otherwise abuse Gmail infrastructure;
- process data on behalf of, or for the benefit of, any third party;
- circumvent any security, rate limit, or access control imposed by Google.
5. Third-party services
The app connects to the Gmail API using Google OAuth 2.0. Use of Google services is governed by Google's own terms and policies, including the Google APIs Terms of Service and the Google API Services User Data Policy. These terms do not replace, modify, or supersede them.
The app is not affiliated with, endorsed by, or sponsored by Google. Google, Gmail, and related marks are the property of their respective owners.
6. No warranty
The app is provided "as is" and "as available", without warranty of any kind, express or implied, including but not limited to the implied warranties of merchantability, fitness for a particular purpose, and non-infringement.
No warranty is given that the app will be uninterrupted, error-free, or that the classification of any particular message will be accurate. Labels are assigned by automated rules and may be incorrect. The operator is responsible for reviewing the results.
7. Limitation of liability
To the maximum extent permitted by applicable law, the operator of the app shall not be liable for any indirect, incidental, special, consequential, or punitive damages, or for any loss of data, messages, labels, profits, or goodwill, arising out of or in connection with the use of or inability to use the app.
Because the app is used solely by its own operator, on their own account, this limitation applies as between the operator and any party that might otherwise claim through them.
8. Intellectual property
The app's source code is the property of its author. Third-party libraries incorporated into the app remain subject to their own licences. Nothing in these terms grants any right to use Google's trademarks, logos, or brand assets beyond what Google's own policies permit.
9. Privacy
The handling of Google user data is described in the Privacy Policy, which forms part of these terms. In summary, the app reads a limited window of message metadata to apply labels, stores no message content, and shares nothing with any third party.
10. Changes to these terms
These terms may be revised if the app's behaviour or the applicable rules change. The current version will always be published on this page with an updated effective date. Continued use of the app after a revision constitutes acceptance of the revised terms.
11. Termination
Use of the app may be discontinued at any time. Access to the relevant Google Account can be revoked at myaccount.google.com/permissions, which immediately ends the app's ability to read or modify anything.
12. Governing law
These terms are governed by the laws of the People's Republic of China, without regard to conflict-of-law principles. Nothing in these terms limits any right that cannot lawfully be limited.
13. Contact
Questions about these terms should be sent to:
These terms were last updated on 4 October 2026.