The short version: your equations are not logged. Where we keep a record, we keep metadata.
1. What we do not collect
No account. No email required to use the web app or the npm package.
The equation text you submit is not written to a log. The MCP server records metadata only (tool name, timestamp, status code, duration).
No language model is in the request path, so nothing is retained by a third-party model provider on your behalf.
2. What we may store
Metering records — only when billing is enabled: an order id, a SHA-256 hash of the request, balance and call count, a timestamp, and source IP. This exists so the meter is auditable and double-charges are detectable.
Access logs — standard web access logs retained for operational security, per host policy.
3. Where it runs
The service is operated by Guangzhou Hongchen Lingjing and may be served from infrastructure outside the EU/EEA, including the United States. Where personal data is processed it is the minimum set listed above; transfers follow a data-protection agreement and, where applicable, Standard Contractual Clauses.
4. Your rights
You can request access, correction, or deletion of the records we hold about you, including meter records tied to an order id.
Contact: privacy@hongchenlingjing.com. We respond within 30 days.
5. Retention
Meter records are retained for the life of the account plus the statutory accounting period. After that they are deleted, not archived.