Terms of Service

Effective date: 18 October 2026 · Last updated: 18 October 2026

1. About these terms

These terms cover Keisan Cards ("the app"), a personal tool operated by Hidenobu Nagai. Using the app means accepting these terms.

2. Scope of use

The app is for the personal use of its owner and a small number of people he knows personally. It is not offered as a public or commercial service, and access is limited to accounts the operator has allowed.

3. What the app does and does not guarantee

Output produced by AI models may be wrong or incomplete. The app is a convenience; it is not a records-management, legal or compliance system.
The operator is responsible for keeping independent backups of anything important. Where the app moves, renames or rewrites files, mistakes are possible.
The app depends on third-party services (including Google, Cloudflare, Vercel, AI providers and, where applicable, LINE). Outages, quota limits, model changes or API changes can interrupt it or change its output.
The app is provided "as is", without warranty of any kind, express or implied, including merchantability, fitness for a particular purpose and non-infringement.

4. Acceptable use

Use the app only on data you are entitled to process, and in compliance with the terms of the services it depends on and with applicable law. Do not use it to access content you are not entitled to access, or to bypass any access control.

5. Limitation of liability

To the maximum extent permitted by law, the operator is not liable for indirect, incidental, special, consequential or punitive damages, nor for any loss of data, files or profits, arising from the use of, or inability to use, the app.

6. Privacy

How the app handles data is described in the Privacy Policy, which forms part of these terms.

7. Changes and termination

The app may be changed, suspended or discontinued at any time without notice, since it serves only its operator and the people he knows. These terms may be updated; the current version is always this page. Access can be ended at any time by revoking the app's access at myaccount.google.com/permissions.

8. Contact

Operated by Hidenobu Nagai. The support address for the app is set as the support address on the app's OAuth consent screen. You can also reach the operator through https://github.com/hidenobunagai.