Terms of Service

1. Who we are

SHEAF is operated by SHEAF LTD, a private limited company registered in England and Wales (company number 17232059) with its registered office at Dormers, Quarry Wood Road, Cookham, Maidenhead, SL6 9UA, United Kingdom. References in these Terms to "SHEAF", "we", "us", or "our" mean SHEAF LTD.

You can reach us at hello@usesheaf.io for general matters or legal@usesheaf.io for matters relating to these Terms.

2. Acceptance of these Terms

By creating a SHEAF account, accessing the SHEAF website (the "Site"), the iOS application, the desktop web application, or any other SHEAF software or service (collectively, the "Service"), you confirm that:

• You have read and understood these Terms;
• You agree to be bound by these Terms and our Privacy Policy;
• You are at least 18 years of age, or the age of majority in your jurisdiction (whichever is higher);
• If you are accepting these Terms on behalf of a business or other organisation, you have authority to bind that organisation.

We require active acceptance of these Terms during account creation. Use of the Service without an account, where permitted, also constitutes acceptance.

3. Description of the Service

SHEAF is a research intelligence platform comprising three primary functions:

• A daily paper feed with AI-scored recommendations personalised to your research interests;
• A knowledge graph that connects the papers you save by concept, author, and semantic similarity;
• An AI writing assistant that produces structured literature reviews and reading paths from your saved collections.

The Service evolves continuously. We may add, remove, or modify features at our discretion, with reasonable notice for material changes that affect your use of paid tiers.

4. Account creation and security

4.1 Account responsibility

You are responsible for the security of your account and all activity that occurs under it. You must:

• Provide accurate and current information when registering;
• Choose a strong, unique password and keep it confidential;
• Notify us promptly at hello@usesheaf.io if you suspect unauthorised access;
• Not share your account credentials with any other person.

Each account is for use by one named individual unless explicitly purchased as part of a multi-seat Enterprise plan.

4.2 Account termination by you

You may close your account at any time from your profile settings. We provide a self-service export endpoint (GET /api/users/me/export) and a self-service deletion endpoint (DELETE /api/users/me) which you can use to download your data or permanently delete it.

5. Subscription plans and billing

5.1 Plans

SHEAF offers the following plans:

• Free — limited daily digest, read-only knowledge graph, two collections.
• Basic — full daily workflow, interactive knowledge graph, AI literature reviews (subject to monthly limits as displayed at point of subscription).
• Pro — Basic plus larger digest, increased review quota, dependency-ordered reading paths.
• Enterprise — multi-seat licences with shared collections, admin controls, API access, SSO, and dedicated support. Available by contract; contact hello@usesheaf.io.

Current pricing and feature limits are published on our Membership page.

5.2 Billing

Paid subscriptions are billed in advance on a monthly or annual basis. Payments are processed by Stripe (Stripe Payments UK Limited). SHEAF does not directly collect, store, or process payment card data; Stripe handles all payment data subject to its own terms and PCI compliance.

If your payment fails, we may suspend access to paid features until payment is restored.

5.3 Cancellation and refunds

You can cancel a paid subscription at any time. Cancellation takes effect at the end of the current billing period, and you retain access to paid features until that date.

We do not offer pro-rated refunds for partial periods. We may offer refunds at our discretion in exceptional circumstances (for example, prolonged service outages).

5.4 Price changes

We may change pricing at any time. For active paying customers, we will provide at least 30 days' advance notice of any price increase, by email and via in-app notice. If you do not accept the new pricing, you may cancel before it takes effect.

6. Acceptable use

You agree to use the Service only for lawful purposes and in accordance with these Terms. You agree to use the Service for:

• Personal research, study, and academic work;
• Internal research, knowledge-management, and writing within a single business or institution (subject to seat limits where applicable).

You agree not to use the Service for any other commercial purpose without our prior written agreement, including resale, sub-licensing, or any service offering substantially based on the SHEAF service or its outputs.

7. Prohibited conduct

You agree that you will not, and will not permit anyone else to:

• Reverse engineer, decompile, disassemble, or otherwise attempt to derive the source code of the Service or any part of it;
• Copy, reproduce, modify, distribute, publicly display, or create derivative works of the Service or any of its components, except as expressly permitted in these Terms;
• Use any automated means (including scrapers, robots, spiders, or AI agents) to extract, harvest, or collect data from the Service or the Site, other than search-engine crawlers operating in accordance with our robots.txt;
• Use the Service or its outputs to train, fine-tune, or develop any artificial intelligence model, machine learning system, or competing product, except for your own personal research where the outputs are not redistributed;
• Attempt to gain unauthorised access to any part of the Service, our systems, other users' accounts, or any network on which the Service is hosted;
• Interfere with, disrupt, or impose an undue burden on the Service or its infrastructure;
• Circumvent or attempt to circumvent any rate limits, usage limits, billing controls, or other technical limitations of the Service;
• Use the Service to submit, transmit, generate, or distribute any content that is unlawful, defamatory, infringing, harassing, hateful, fraudulent, or that violates the rights of any third party;
• Share, sub-licence, or otherwise transfer your account credentials or access rights to any third party;
• Misrepresent your identity or affiliation in connection with the Service.

Violation of this section may result in immediate suspension or termination of your account and may result in further legal action.

8. Intellectual property

8.1 Our intellectual property

The Service, the Site, and all related software, content, design, brand marks (including "SHEAF" and the SHEAF wordmark), trade marks, trade dress, look and feel, structure, organisation, and underlying technology are the exclusive property of SHEAF LTD and are protected by intellectual property laws including copyright, trade mark, database rights, and trade secret law in the United Kingdom and other jurisdictions.

"SHEAF" is the subject of UK trade mark application UK00004390181 (pending registration) filed in International Classes 9 and 42. All other rights are reserved at common law.

We grant you a limited, non-exclusive, non-transferable, revocable licence to access and use the Service for its intended purposes during the term of these Terms. We grant you no other rights, express or implied.

8.2 Your content

You retain ownership of any content you submit to the Service (for example, your interest profile, ratings, collections, notes, and any documents you upload via the BibTeX/RIS import). By submitting content to the Service you grant SHEAF a worldwide, non-exclusive, royalty-free licence to host, store, process, transmit, and display that content solely as necessary to provide the Service to you. We do not claim ownership of your content, and we will not use it for any other purpose without your explicit consent (see our Privacy Policy).

8.3 Third-party content

The Service surfaces academic papers and metadata sourced from arXiv, bioRxiv, PubMed, CrossRef, ChemRxiv, OpenAlex, Semantic Scholar, and similar academic data sources. Rights to those papers belong to their respective authors and publishers. The Service makes papers discoverable; it does not grant any additional rights in the underlying papers.

9. AI-generated outputs

SHEAF uses third-party large language models (currently provided by Anthropic) to generate scores, summaries, literature reviews, and reading paths (collectively, "AI Outputs"). The following applies to AI Outputs:

• As between you and SHEAF, you may use AI Outputs generated for your account for your own personal research and writing, including incorporating them into your own work product (subject to the prohibited-conduct restrictions in section 7);
• AI Outputs may contain inaccuracies, omissions, or fabricated citations. You are responsible for verifying any AI Output before relying on it. SHEAF makes no warranty as to the accuracy, completeness, or fitness of any AI Output for any particular purpose;
• AI Outputs are generated automatically and are not reviewed by a human before delivery. The scoring and ranking system is, in part, an automated decision-making system within the meaning of UK General Data Protection Regulation Article 22 — see our Privacy Policy for details on your rights regarding automated decisions.

10. Beta and confidentiality

During the period before the Service is generally available (the "Beta Period"), or while you are given access to any feature designated as "beta", "preview", or "early access", you agree to keep confidential any non-public information you observe about the Service, including:

• Performance characteristics, response times, and accuracy of AI Outputs;
• Implementation details and product architecture;
• Features not yet publicly announced;
• Bugs, defects, and limitations of pre-release features.

You may write about your own experience using the Service in general terms, but you agree not to publish screenshots, performance benchmarks, or feature lists of any non-public feature without our prior written consent.

Feedback you choose to share with us about the Service may be used by SHEAF without restriction and without obligation to compensate you.

11. Privacy and data protection

Your use of the Service is also governed by our Privacy Policy, which explains what personal data we collect, how we use it, and your rights under UK GDPR, EU GDPR, and other applicable privacy laws. By using the Service, you confirm you have read and understood the Privacy Policy.

12. Third-party services and sub-processors

The Service depends on a number of third-party services to operate. The most significant of these include:

• Anthropic PBC — provides the large language models used for AI Outputs;
• Stripe Payments UK Limited — handles all subscription billing and payment processing;
• Oracle Cloud Infrastructure — provides the hosting infrastructure;
• Sentry (Functional Software, Inc.) — error tracking and observability;
• Apple Inc. — distributes the iOS app via the App Store (and, where SHEAF push notifications are enabled in future, operates push-notification delivery).

A full and current list of sub-processors is maintained in our Privacy Policy. Each of these third parties is subject to its own terms of service and privacy policy.

13. Service availability

We will use reasonable efforts to make the Service available to you with reasonable uptime, but we do not guarantee uninterrupted, error-free, or uninterrupted operation. The Service may be unavailable from time to time for scheduled maintenance, unscheduled emergency maintenance, third-party outages (including Oracle Cloud, Anthropic, or Stripe), or other reasons beyond our control.

For Free-tier users, no service-level commitment is made. For Basic and Pro paid subscribers, we will use commercially reasonable efforts to maintain availability. Enterprise customers may negotiate a written service-level agreement separately.

14. Disclaimers

To the maximum extent permitted by law:

• The Service is provided "as is" and "as available", without warranties of any kind, whether express, implied, statutory, or otherwise;
• We disclaim all warranties of merchantability, fitness for a particular purpose, non-infringement, and any warranties arising out of course of dealing or usage of trade;
• We make no warranty that the Service will meet your requirements, operate without interruption, or be free from errors, viruses, or other harmful components;
• We make no warranty as to the accuracy, completeness, currency, or quality of any content within the Service, including paper metadata, AI Outputs, or the knowledge graph.

Nothing in these Terms limits or excludes any liability that cannot be limited or excluded under UK law, including liability for death or personal injury caused by negligence, fraud or fraudulent misrepresentation, or any other liability that cannot be excluded.

15. Limitation of liability

To the maximum extent permitted by law:

• SHEAF, our directors, officers, employees, contractors, and licensors shall not be liable for any indirect, incidental, consequential, special, exemplary, or punitive damages, including loss of profit, loss of business, loss of data, loss of goodwill, or loss of opportunity, arising out of or in connection with the Service or these Terms, whether based in contract, tort (including negligence), or any other theory of liability;
• Our total aggregate liability arising out of or in connection with the Service or these Terms shall not exceed the amount you paid SHEAF for the Service in the twelve (12) months immediately preceding the event giving rise to the liability. For users of the Free tier who have made no payment, this cap shall not exclude any liability that cannot lawfully be excluded;
• These limitations apply even if SHEAF has been advised of the possibility of such damages and even if a remedy fails of its essential purpose.

16. Indemnification

You agree to indemnify and hold harmless SHEAF, our directors, officers, employees, and contractors from and against any claim, demand, loss, liability, damage, or expense (including reasonable legal fees) arising out of or related to:

• Your use of the Service in violation of these Terms;
• Your violation of any law or the rights of any third party;
• Any content you submit to the Service;
• Your misrepresentation of any fact in connection with the Service.

17. Suspension and termination

We may suspend or terminate your access to the Service, with or without notice, if:

• You materially breach these Terms;
• We are required to do so by applicable law or court order;
• Your account presents a security risk to other users or to the Service itself;
• Your account has been inactive for an extended period (we will give reasonable advance notice in this case).

You may terminate your account at any time as described in section 4.2. Sections that by their nature should survive termination — including sections on intellectual property, disclaimers, limitation of liability, indemnification, governing law, and miscellaneous — will survive any termination.

18. Modifications to these Terms

We may update these Terms from time to time. If we make material changes, we will notify you in advance by email (at the address on file with your account) and via in-app notice, and we will update the "Last updated" date at the top of this document. Material changes will take effect at least 14 days after notice. Your continued use of the Service after the effective date constitutes acceptance of the updated Terms.

Non-material changes (typo corrections, clarifications that do not change the substance of the Terms) take effect immediately on posting.

19. Governing law and jurisdiction

These Terms and any non-contractual obligations arising out of or in connection with them are governed by the laws of England and Wales.

You agree to submit to the exclusive jurisdiction of the courts of England and Wales in respect of any dispute or claim arising out of or in connection with these Terms or the Service. If you are a consumer resident in another part of the United Kingdom, you may also bring proceedings in the courts of the part of the UK in which you reside.

20. Contact

For questions about these Terms, you can reach us at:

• General: hello@usesheaf.io
• Legal and compliance: legal@usesheaf.io
• Post: SHEAF LTD, Dormers, Quarry Wood Road, Cookham, Maidenhead, SL6 9UA, United Kingdom

21. Miscellaneous

21.1 Entire agreement

These Terms, together with the Privacy Policy and any other policies or terms expressly referenced, constitute the entire agreement between you and SHEAF concerning the Service, and supersede any prior agreements between you and SHEAF on the same subject matter.

21.2 Severability

If any provision of these Terms is found to be unenforceable or invalid by a court of competent jurisdiction, that provision will be modified to the minimum extent necessary to make it enforceable, and the remaining provisions will continue in full force and effect.

21.3 No waiver

Our failure to enforce any right or provision of these Terms will not be deemed a waiver of that right or provision. Any waiver must be in writing and signed by an authorised representative of SHEAF.

21.4 Assignment

You may not assign or transfer your rights or obligations under these Terms without our prior written consent. We may assign these Terms in connection with a merger, acquisition, sale of assets, or by operation of law, with notice to you.

21.5 Third-party beneficiaries

Except as expressly provided in these Terms, no third party shall have any right to enforce any provision of these Terms under the Contracts (Rights of Third Parties) Act 1999.

21.6 Force majeure

Neither party will be liable for any failure or delay in performance under these Terms due to causes beyond its reasonable control, including acts of God, war, terrorism, riots, embargoes, acts of civil or military authorities, fire, flood, accidents, network or internet failures, or shortages of transportation, facilities, fuel, energy, labour, or materials.