The Service is not directed to children under 13. By using the Service you represent that you are at least 13 years old, or the minimum age of digital consent in your location, whichever is higher. If you are a parent or guardian and a minor in your care is using the Service, you are responsible for supervising that use and for the minor's compliance with these terms.

You are responsible for keeping your account credentials secure and for all activity that occurs under your account. You must provide accurate account information and notify us promptly of any unauthorized access. We may refuse, suspend, or terminate accounts at our discretion, including to protect the Service, enforce these terms, or comply with applicable law.

You may use the Service only for lawful chess analysis, study, and account management. The Acceptable Use Policy is incorporated into these terms by reference. Violations of the Acceptable Use Policy are violations of these terms.

You retain ownership of the chess games, PGNs, annotations, prompts, and feedback text you submit (“User Content”). You grant zen.reinit.net a worldwide, non-exclusive, royalty-free licence to host, store, copy, process, transmit, display, and create derivative works of User Content solely as needed to operate, maintain, secure, debug, and improve the Service. This licence ends when you delete the relevant User Content, except to the extent retention is required for backups, security investigations, abuse review, or legal obligations.

You represent and warrant that you have all rights necessary to submit your User Content and that it does not infringe any third party's rights or violate any law.

Cassia combines a deterministic chess analysis pipeline with Stockfish evaluation and templated explanations. An optional AI-assisted layer may rephrase or expand facts established by that pipeline. The AI Disclosure describes what may be sent, where it may be sent, and what is logged.

Cassia output, engine evaluations, classifications, and accuracy estimates are provided as study aids only. They may be incomplete, incorrect, or misleading and must not be treated as authoritative analysis, tournament advice, or any form of professional guidance. You are responsible for independently verifying anything you rely on.

When you flag a Cassia response or submit feedback, we store the position, the relevant moves, the classification, the Cassia text that was shown to you, any reason you provide, and your account identifier. We use this feedback to investigate failures and improve the Service. By submitting feedback you grant us a perpetual, irrevocable, royalty-free licence to use the submission for product improvement, internal testing, and quality review. Do not include sensitive personal information in feedback text.

The Service may link to an external Ko-fi page where you can voluntarily support development. Donations are processed entirely by Ko-fi under Ko-fi's own terms and privacy policy. zen.reinit.net does not process card data, store payment information, or receive personally identifying payment details. Donations are voluntary, non-refundable through us, do not create any contractual right to features, support, or continued availability of the Service, and do not modify these terms.

The Service is offered in an evolving beta state. We may add, modify, degrade, restrict, or remove features, quotas, providers, integrations, or entire portions of the Service at any time, with or without notice. We do not guarantee uptime, response time, or that the Service will be free of errors, defects, or interruptions.

We may suspend or terminate your access at any time, with or without notice, including to protect the Service, investigate suspected abuse, comply with law or third-party requests, or enforce these terms. You may stop using the Service at any time. Sections that by their nature should survive termination (including ownership, licences granted to us, disclaimers, limitation of liability, indemnification, and dispute terms) will survive.

THE SERVICE, INCLUDING ALL COACH OUTPUT, ENGINE ANALYSIS, EVALUATIONS, CLASSIFICATIONS, AND ANY AI OUTPUT, IS PROVIDED “AS IS” AND “AS AVAILABLE” WITHOUT WARRANTIES OF ANY KIND, WHETHER EXPRESS, IMPLIED, OR STATUTORY. TO THE MAXIMUM EXTENT PERMITTED BY LAW, WE DISCLAIM ALL WARRANTIES, INCLUDING MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, RELIABILITY, NON-INFRINGEMENT, AND THAT THE SERVICE WILL BE UNINTERRUPTED, SECURE, OR ERROR-FREE.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, ZEN.REINIT.NET AND THE PEOPLE BEHIND IT WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMAGES, OR FOR ANY LOSS OF PROFITS, REVENUES, DATA, GOODWILL, RATING POINTS, OR OTHER INTANGIBLE LOSSES, ARISING OUT OF OR RELATED TO YOUR USE OF THE SERVICE, EVEN IF WE HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. OUR TOTAL AGGREGATE LIABILITY FOR ALL CLAIMS RELATED TO THE SERVICE WILL NOT EXCEED THE GREATER OF (A) THE AMOUNTS, IF ANY, YOU PAID DIRECTLY TO ZEN.REINIT.NET IN THE THREE MONTHS BEFORE THE CLAIM AROSE, OR (B) FIFTY UNITED STATES DOLLARS (US$50). SOME JURISDICTIONS DO NOT ALLOW CERTAIN LIMITATIONS, IN WHICH CASE THE ABOVE LIMITATIONS APPLY ONLY TO THE EXTENT PERMITTED.

You agree to defend, indemnify, and hold harmless zen.reinit.net and the people behind it from and against any claims, liabilities, damages, losses, and expenses (including reasonable legal fees) arising out of or related to your User Content, your use of the Service, your violation of these terms, or your violation of any law or third-party right.

The Service, including its software, design, text, and branding (excluding User Content), is owned by zen.reinit.net or its licensors and is protected by intellectual property laws. You receive no licence to zen.reinit.net trademarks or proprietary materials except as needed to use the Service as intended.

If you believe content on the Service infringes your copyright, send a notice to [email protected] identifying the work, the allegedly infringing material and its location, your contact information, a good-faith statement that the use is not authorized, a statement under penalty of perjury that the notice is accurate and you are the rights holder or authorized to act on their behalf, and your physical or electronic signature. We may remove or disable access to content we believe in good faith to be infringing and may terminate accounts of repeat infringers.

We may update these terms from time to time. When we do, we will revise the “Last updated” date above. For material changes we will use reasonable effort to provide additional notice (for example, in-product or by email). Your continued use of the Service after the updated terms take effect constitutes acceptance of the changes. If you do not accept the updated terms, stop using the Service.

These terms and any dispute arising out of or related to them or the Service will be governed by the laws of the operator's place of residence at the time the dispute arises, without regard to conflict-of-law rules. You and zen.reinit.net agree to attempt to resolve any dispute informally first by contacting [email protected]. Nothing in these terms limits any non-waivable rights you may have under the mandatory consumer law of your country of residence.

These terms, together with the documents they reference, constitute the entire agreement between you and zen.reinit.net regarding the Service. If any provision is held unenforceable, the remaining provisions remain in effect. Our failure to enforce a provision is not a waiver. You may not assign these terms; we may assign them to an affiliate or successor. There are no third-party beneficiaries.

Questions about these terms can be sent to [email protected].