Terms of Service

Last updated: March 4, 2026

1. Agreement to Terms

By accessing or using Stone AI, Best AI, My Best AI, or any related services, applications, APIs, or websites (collectively, "the Service"), you agree to be bound by these Terms of Service ("Terms"). If you do not agree to these Terms, do not use the Service. The Service is owned and operated by Stone AI ("we", "us", "our", "Company"). These Terms constitute a legally binding agreement between you ("User", "you", "your") and Stone AI.

2. Description of Service

Stone AI is an AI-powered platform that provides conversational AI chat, specialized AI agents, AI companion ("Bestie") features, a community forum, and API access. The Service offers both local AI inference (processed on our hardware) and cloud AI inference (processed via third-party providers) depending on your subscription tier and settings. "Best AI" and "My Best AI" are companion products and extensions of the Stone AI platform, subject to these same Terms.

3. Account Registration

You must create an account to use the Service. You are responsible for maintaining the security of your account credentials and for all activity that occurs under your account. You must provide accurate, current, and complete information during registration. You must be at least 18 years old to use the Service. One person may not maintain more than one account. Sharing accounts is prohibited and may result in immediate termination without refund.

4. Subscription Plans and Billing

Stone AI offers free and paid subscription tiers. Paid subscriptions are billed through Stripe on a monthly, semi-annual, or annual basis depending on the billing period you select. By subscribing to a paid plan, you authorize us to charge your payment method on a recurring basis. You may cancel your subscription at any time through the billing portal. Cancellations take effect at the end of the current billing period. No refunds are provided for partial billing periods, unused credits, or tier downgrades. We reserve the right to change pricing with 30 days notice to existing subscribers; new subscribers are subject to current pricing.

Free trial periods may be offered at our discretion. Free trials are limited to one per person, household, and payment method. Abuse of free trials (including creating multiple accounts) will result in account termination. Enhanced free trials that require a payment method will automatically convert to a paid subscription at the end of the trial period unless canceled before the trial ends.

5. Advertising and Sponsored Content

The Service may display advertisements, sponsored content, and promotional materials on ad-supported tiers, including the Free tier. By using the Service, you acknowledge and consent to the display of such content as part of the ad-supported experience. Paid subscription tiers provide an ad-free experience. We reserve the right to determine the placement, format, and frequency of advertising content. Advertisements may be contextually targeted based on anonymized usage patterns as described in our Privacy Policy.

6. Usage Limits

Each subscription tier has defined usage limits including daily messages, monthly tokens, concurrent requests, and response length. Exceeding these limits may result in temporary throttling until the next reset period. Usage limits reset daily (messages) and monthly (tokens) based on UTC time. Attempting to circumvent usage limits through any means (including but not limited to multiple accounts, automated tools, or API abuse) constitutes a material breach of these Terms.

7. AI Agents and Bestie Companions

AI agents are specialized conversational assistants with domain-specific knowledge. AI Bestie companions are personalized conversational AI characters created and customized by users. Agent and Bestie availability depends on your subscription tier. Both provide informational guidance only and do not constitute professional advice. You should not rely on agent or Bestie output as a substitute for qualified professional counsel in legal, medical, financial, engineering, or compliance matters. Stone AI is not liable for any actions taken based on AI-generated advice.

8. API Access and Reselling

API access is available on the Pro plan. You may use the API to build products and services, including reselling AI capabilities to your own customers, subject to the Stone AI Reseller Agreement (available at /reseller-agreement). All reseller activity requires a separate executed Reseller Agreement. Unauthorized reselling is a material breach of these Terms and may result in immediate termination, forfeiture of all revenue generated through unauthorized resale, and legal action.

API usage is subject to the same rate limits as your subscription tier. You are responsible for your end users' compliance with these Terms. You may not misrepresent AI-generated output as human-created. You may not use the API for illegal purposes, spam, or generating harmful content. Stone AI reserves the right to revoke API access at any time for violations.

9. Community Forum

The community forum is provided for users to share tips, ask questions, and interact with each other. You retain ownership of content you post. By posting, you grant Stone AI a perpetual, worldwide, royalty-free, non-exclusive license to display, reproduce, distribute, and create derivative works from your content on the platform and in marketing materials. You may not post content that is illegal, harassing, defamatory, or violates the rights of others. We reserve the right to remove content and suspend accounts that violate these guidelines without notice.

10. Acceptable Use

You agree not to:

  • Use the Service to generate illegal, harmful, deceptive, or defamatory content
  • Attempt to bypass rate limits, security measures, or access controls
  • Reverse engineer, decompile, disassemble, or extract the AI models, algorithms, or training data
  • Use automated tools to scrape, crawl, or bulk-access the Service
  • Share your account credentials or API keys with unauthorized parties
  • Impersonate other users, Stone AI staff, or any third party
  • Upload malicious code, viruses, or exploit vulnerabilities
  • Use the Service to compete with or build a competing product to Stone AI
  • Resell, sublicense, or redistribute access to the Service without a valid Reseller Agreement
  • Use the Service to train, fine-tune, or develop competing AI models
  • Engage in prompt injection, jailbreaking, or attempts to extract system prompts
  • Misrepresent your identity, tier, or relationship with Stone AI

11. Intellectual Property and Trademarks

You own the content you create using the Service, including AI-generated outputs produced from your prompts. Stone AI retains all right, title, and interest in the platform, AI models, agent configurations, agent prompts, knowledge bases, Bestie personality system, brand assets, trademarks, trade dress, and all underlying technology. The names "Stone AI", "Best AI", "My Best AI", and all associated logos, insignias, designs, and trade dress are trademarks or pending trademarks of Stone AI. You may not copy, redistribute, sell, license, or create derivative works from Stone AI's proprietary technology or brand assets.

Trademark Usage: You may not use Stone AI trademarks, logos, or brand assets without prior written permission. Authorized use (e.g., by approved resellers) must comply with our Brand Guidelines. Any unauthorized use of our trademarks will be met with legal action. You may not register domain names, social media accounts, or business names that are confusingly similar to Stone AI, Best AI, or My Best AI trademarks.

12. Brand Protection

Stone AI takes its brand integrity seriously. You agree not to:

  • Use Stone AI's name, logo, or trademarks in any way that suggests endorsement, affiliation, or sponsorship without written authorization
  • Register or use any domain name, trademark, or business name that is confusingly similar to any Stone AI trademark
  • Create or distribute marketing materials that misrepresent the nature of your relationship with Stone AI
  • Modify, distort, or use Stone AI brand assets in a way that diminishes or tarnishes the brand
  • Engage in keyword advertising, SEO manipulation, or social media practices that trade on Stone AI's brand reputation

Violations of brand protection provisions entitle Stone AI to seek immediate injunctive relief without posting bond, in addition to any other remedies available at law or equity.

13. Confidentiality

You acknowledge that through use of the Service, you may have access to information that is confidential to Stone AI, including but not limited to system prompts, agent configurations, pricing structures, business strategies, and technical architecture ("Confidential Information"). You agree to maintain the confidentiality of all Confidential Information and not to disclose it to any third party. This obligation survives termination of your account for a period of three (3) years.

14. Indemnification

You agree to indemnify, defend, and hold harmless Stone AI, its officers, directors, employees, agents, and affiliates from and against any and all claims, damages, losses, liabilities, costs, and expenses (including reasonable attorneys' fees) arising out of or related to: (a) your use of the Service; (b) your violation of these Terms; (c) your violation of any third-party rights; (d) content you create, distribute, or make available through the Service; or (e) any reselling activity conducted through your account. This indemnification obligation survives termination of your account.

15. Disclaimers

THE SERVICE IS PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, AND ACCURACY. AI-generated content may contain errors, inaccuracies, hallucinations, or biases. Stone AI does not guarantee the accuracy, completeness, timeliness, or reliability of any AI output. The Service is not a substitute for professional advice. We are not liable for decisions made based on AI-generated content. Service availability is not guaranteed and may be interrupted for maintenance, updates, or unforeseen circumstances.

16. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, STONE AI'S TOTAL AGGREGATE LIABILITY ARISING OUT OF OR RELATED TO THESE TERMS OR THE SERVICE SHALL NOT EXCEED THE GREATER OF (A) THE AMOUNTS YOU PAID TO STONE AI IN THE TWELVE (12) MONTHS PRECEDING THE CLAIM, OR (B) ONE HUNDRED U.S. DOLLARS ($100). IN NO EVENT SHALL STONE AI BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMAGES, INCLUDING LOSS OF PROFITS, DATA, GOODWILL, OR BUSINESS OPPORTUNITIES, REGARDLESS OF WHETHER SUCH DAMAGES WERE FORESEEABLE OR WHETHER STONE AI WAS ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

17. Dispute Resolution and Arbitration

Any dispute, claim, or controversy arising out of or relating to these Terms or the Service shall be resolved through binding arbitration administered by the American Arbitration Association ("AAA") under its Commercial Arbitration Rules. Arbitration shall take place in the state where Stone AI is headquartered. The arbitrator's award shall be final and binding. Judgment on the award may be entered in any court of competent jurisdiction.

CLASS ACTION WAIVER: You agree that any dispute resolution proceedings will be conducted only on an individual basis and not in a class, consolidated, or representative action. If this class action waiver is found to be unenforceable, the entirety of this arbitration provision shall be null and void.

Exception: Either party may seek injunctive or other equitable relief in any court of competent jurisdiction to prevent the actual or threatened infringement, misappropriation, or violation of intellectual property rights or confidentiality obligations.

18. Governing Law

These Terms shall be governed by and construed in accordance with the laws of the United States and the state where Stone AI is headquartered, without regard to conflict of law principles. For any matters not subject to arbitration, exclusive jurisdiction and venue shall be in the state and federal courts located in Stone AI's headquarter jurisdiction.

19. Account Termination

We may suspend or terminate your account immediately and without notice for violations of these Terms, abusive behavior, suspected fraud, or non-payment. You may delete your account at any time by contacting support. Upon termination: (a) all licenses granted to you under these Terms immediately cease; (b) you must immediately stop using the Service and any Stone AI materials; (c) your data will be deleted within 30 days, except as required by law or for legitimate business purposes; (d) any outstanding fees become immediately due and payable; (e) Sections 11-18 survive termination.

20. Non-Circumvention

You agree not to circumvent, avoid, or bypass Stone AI in any business relationship or transaction introduced or facilitated through the Service. This includes but is not limited to: directly contacting or soliciting Stone AI's AI model providers, infrastructure partners, or other vendors with the intent to bypass Stone AI's platform. Violation of this provision entitles Stone AI to damages equal to the value of the circumvented transaction plus reasonable attorneys' fees.

21. Audit Rights

Stone AI reserves the right to audit your use of the Service, API, and any reselling activity to ensure compliance with these Terms. You agree to cooperate with any such audit and to provide access to relevant records upon reasonable notice. For Pro and API users, Stone AI may conduct automated monitoring of API usage patterns to detect violations.

22. Force Majeure

Stone AI shall not be liable for any failure or delay in performance resulting from causes beyond its reasonable control, including but not limited to acts of God, natural disasters, pandemic, war, terrorism, government actions, internet or telecommunications failures, power outages, or third-party service provider failures.

23. Severability

If any provision of these Terms is found to be unenforceable or invalid, that provision shall be limited or eliminated to the minimum extent necessary so that these Terms shall otherwise remain in full force and effect. The unenforceability of any provision shall not affect the validity of any other provision.

24. Entire Agreement

These Terms, together with the Privacy Policy and any applicable Reseller Agreement, constitute the entire agreement between you and Stone AI regarding the Service and supersede all prior agreements, understandings, negotiations, and discussions, whether oral or written. No waiver of any provision shall be deemed a further or continuing waiver of such provision or any other provision.

25. Changes to Terms

We may update these Terms at any time. Material changes will be communicated via email or in-app notification at least 14 days before taking effect. Continued use of the Service after changes constitutes acceptance of the updated Terms. If you do not agree to the updated Terms, you must stop using the Service before the changes take effect.

26. Contact

For questions about these Terms, contact us at legal@stone-ai.net or support@stone-ai.net.