Belief Systems

Belief Systems – Terms of Service

Last Updated: August 29, 2026

These Terms of Service (“Terms”) govern your access to and use of the Belief Systems website, indices, data, analytics, and related services (collectively, the “Services”).

By accessing or using the Services, you agree to be bound by these Terms. If you do not agree, do not access or use the Services.

Changes to these Terms. We may revise these Terms. Revisions are effective on the Last Updated date shown above and apply prospectively. Your continued use of the Services after that date, and in any event your acceptance of the revised version in the developer portal, constitutes acceptance.

1. Provider; Assignment

The Services are provided by True Craft Ventures LLC, an Oregon limited liability company doing business as Belief Systems (“Belief Systems,” “we,” “us,” or “our”).

Belief Systems may assign or transfer these Terms and all associated rights and obligations to any affiliate, successor, or acquiring entity without prior notice to you. Such assignment shall not materially diminish your rights under these Terms.

2. Eligibility

You must be at least 18 years old and legally capable of entering into binding contracts to access or use the Services.

By using the Services, you represent and warrant that:

  • You are not prohibited from using the Services under applicable law; and
  • Your use of the Services complies with these Terms and all applicable laws and regulations.

3. Nature of the Services

Belief Systems is a benchmark administrator and data publisher. The Services consist of informational and research-oriented index data and analytics derived from publicly available prediction-market prices.

No investment products. The indices are theoretical, rules-based measurements. No assets track them, no fund or vehicle replicates them, and no interest in them can be acquired from or through Belief Systems. Belief Systems does not offer or accept any account, deposit, subscription, or investment of any kind. Index values are calculated quantities, not net asset values of any fund or portfolio. Nothing on or through the Services constitutes an offer to sell, or a solicitation of an offer to buy, any security or other financial instrument.

The Services are experimental and may change, pause, or terminate at any time.

4. No Advice; No Fiduciary Relationship

Nothing in the Services constitutes investment, financial, legal, or tax advice, or a recommendation or endorsement of any transaction or strategy. Belief Systems does not act as a broker, dealer, investment adviser, fiduciary, or agent for any user. You should consult your own advisors before making any financial decision.

5. Methodology, Accuracy, and Changes

All indices, analytics, values, and methodologies:

  • Are informational and model-based
  • May be incomplete, delayed, or erroneous
  • Are subject to change, subject to the notice practices described below

Index levels and related performance figures are informational, non-executable values computed from constituent market prices under the published methodology; they do not reflect trading fees, spreads, slippage, or market impact, and no result shown could necessarily be realized by trading. Belief Systems may modify, suspend, or discontinue any index, methodology, or feature. Where the published Index Governance policy specifies notice periods, correction windows, or disclosure practices, Belief Systems follows them; that policy is a statement of practice and does not limit this reservation where law, regulation, venue failure, or other events outside Belief Systems' reasonable control require otherwise.

Past performance does not guarantee future results.

6. No Reliance

You agree that:

  • You use the Services entirely at your own risk;
  • You will not rely on the Services as the sole basis for any financial decision; and
  • Any decisions you make based on the Services are your sole responsibility, made in consultation with your own advisors.

7. Data License and Acceptable Use

Ownership. The Belief Indices and the other data products Belief Systems publishes, including Belief Volatility series and any further index, volatility, or analytic families we publish — including levels, readings, constituent compositions and weights, reconstitution history, methodologies, and all derived analytics (collectively, the "Index Data") — are proprietary to Belief Systems. The underlying prediction-market probabilities are publicly available; the Index Data — the rules-based aggregation, the point-in-time archive, and the governed methodology — is not. The Index Data is licensed, not placed in the public domain.

Registered access — the free tier. The Index Data is distributed through three channels, each of which requires a registered account: the Data API at api.beliefsystems.xyz, the Model Context Protocol (MCP) endpoint at beliefsystems.xyz/api/mcp, and snapshot file downloads from the Data page and the developer portal. The Data API and the MCP endpoint require a valid API key presented in an authorization header; snapshot downloads require a valid API key or an authenticated browser session.

Subject to your continuing compliance with these Terms, Belief Systems grants you a limited, revocable, non-exclusive, non-transferable, non-sublicensable right to access and use the Index Data through those channels for evaluation, research, and internal business analytics. This grant is conditioned on (i) registration of an account with accurate, current, and complete information, (ii) your acceptance of these Terms, and (iii) your observance of the rate, request-volume, and history limits published at docs.beliefsystems.xyz/data-access/data-api-limits, as those limits are published from time to time. We may change those limits; changes apply prospectively from publication and do not make prior use a breach. Any Index Data you publish, quote, display, or otherwise make available to any person outside your organization must carry the attribution "Source: Belief Systems (beliefsystems.xyz)."

How this grant is accepted. You accept these Terms for purposes of this grant by affirmatively indicating acceptance in the developer portal before creating your first API key. We record the version and content hash of the Terms you accepted, the date and time, and the network address and user agent from which acceptance was submitted. If these Terms are revised, we will require acceptance of the revised version before you create a further key; keys already issued remain governed by the version in effect when they were issued until you accept the revision.

API keys and session credentials are issued to, and personal to, the individual who registered the account; they may not be shared with, used by, or operated on behalf of any other individual, including colleagues within your organization, and accounts may not be pooled. Each individual requiring access must register separately. A key may run in scripts and systems the account holder operates as part of the use this grant permits. If you use the Services in the course of your work for an organization, you are responsible for ensuring that use complies with these Terms; if you have authority to bind that organization, "you" and "your" also include it. You are responsible for all activity conducted through your account and keys, and you must notify us promptly upon learning of any unauthorized use.

The registration requirement, the API-key requirement, and the published rate, volume, and history limits are access controls under the acceptable-use terms below. Circumventing them — including by registering more than one account, using another person's account or key, distributing requests in order to obtain more request volume than the published per-key limits allow, or scraping around the registration gate — is prohibited.

Usage records. We log the requests made with your key or session, including the route called, the time of the call, and a hashed network address, and we may use those records to operate the Services, enforce the published limits, and verify compliance with this Section. How that information is collected, used, and retained is described in our Privacy Policy.

Citation and quotation. You may quote, cite, and display individual Index Data values and figures derived from them in research, commentary, and editorial work, including externally published work, provided each such use carries the attribution above and does not amount to the redistribution of a substantial portion of the Index Data or to a substitute for access to the Services. This permission does not extend to bulk or systematic reproduction, which is addressed below.

This grant does not include, and a separate written license through Index Services is required for, each of the following:

  • Redistribution, resale, or other provision of Index Data to any third party, whether or not for a fee, except to the extent expressly permitted by the CC BY-NC 4.0 license and editorial-use grant described below as to the contents of snapshot files;
  • Incorporation of Index Data into any product, service, feed, benchmark, fund, or index-linked instrument;
  • Use of Index Data in any production system, whether internal or external, on which you or any third party relies for operational, valuation, settlement, or risk-management purposes; and
  • Extraction or accumulation of Index Data in excess of the rate and request-volume limits published for your keys, or by any means designed to evade those limits.

For the avoidance of doubt, evaluation, research, and internal business analytics conducted within your organization remain within this grant, and use by a commercial entity is not, by itself, outside it; what requires a license is the distribution, productization, and reliance described above.

Belief Systems may modify, restrict, suspend, or terminate any channel, any account or key, or this grant at any time, with or without notice.

Snapshot content license — research and editorial use. Access to snapshot files is governed by the registered-access grant above. The license on their contents is unchanged: the point-in-time dataset snapshots we publish are made available free of charge for non-commercial research and editorial use under the Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0), together with a limited editorial-use grant, provided each use carries the attribution "Source: Belief Systems (beliefsystems.xyz)." Journalists and researchers may reproduce and cite the Index Data contained in a snapshot on these terms without a separate agreement. That content license governs what you may do with a snapshot file you have obtained through your registered account; it is not itself a right of access, and it does not displace the registration, key, and access-control requirements of this Section, which govern access to the Services. Where the CC BY-NC 4.0 license permits a use of snapshot contents that this Section would otherwise restrict, the CC BY-NC 4.0 license controls as to those contents. The rights CC BY-NC 4.0 grants over a snapshot file you have already obtained are not revoked by termination of your account, your key, or the registered-access grant; what terminates is your right of further access. The dated archive index pages at beliefsystems.xyz/data/archive remain publicly available and may be cited and linked freely.

Licensed tier — commercial and systematic use. Any other use requires a separate written license through Index Services. This includes, without limitation: live or programmatic data feeds; automated, bulk, or systematic extraction of Index Data from this website or its interfaces, or from any distribution channel beyond the published limits of the registered free tier; redistribution or resale; incorporation into any product, benchmark, fund, or index-linked instrument; and any other commercial use. Registered access under this Section is an evaluation and internal-analytics grant and is not a licensed data feed: it confers no service level, no continuity or availability commitment, no right of reliance, and no production rights. The public website and its endpoints are likewise not a licensed data feed; accessing any of them as one confers no license and is prohibited under the acceptable-use terms below.

Acceptable use. You agree not to:

  • Share, publish, sell, or transfer an API key or session credential, or use a credential issued to another account;
  • Register more than one account, or use another person's account or key, in order to obtain more request volume than the published per-key limits allow;
  • Scrape, crawl, or systematically extract Index Data from the Services, including from public pages, in excess of the published limits or in order to avoid the registration requirement;
  • Circumvent, defeat, or attempt to defeat the registration, key, rate-limit, or session access controls on the Data API, the MCP endpoint, or snapshot files, or any other security measure;
  • Provide false or misleading registration information;
  • Interfere with or disrupt the Services;
  • Introduce malware or malicious code;
  • Use the Services in violation of applicable law.

8. Suspension and Termination

Belief Systems reserves the right to suspend or terminate access to the Services, in whole or in part, at its sole discretion and without liability, including to protect system integrity or manage risk.

Sections 4, 6, 7 (as to Index Data already obtained), 9, 10, 11, 12, and 13 survive any termination or suspension of your access. On termination you must cease accessing the Services through the affected account or key. Rights already granted to you under the CC BY-NC 4.0 license on snapshot contents are unaffected.

9. Disclaimers

THE SERVICES ARE PROVIDED “AS IS” AND “AS AVAILABLE.”

TO THE MAXIMUM EXTENT PERMITTED BY LAW, BELIEF SYSTEMS AND ITS MEMBERS, MANAGERS, OFFICERS, AND AGENTS DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, AND NON-INFRINGEMENT.

10. Limitation of Liability

Subject to the carve-outs below, and to the maximum extent permitted by law, in no event shall Belief Systems, its members, managers, officers, or agents be liable for any indirect, incidental, consequential, special, exemplary, or punitive damages arising out of your use of the Services, and their aggregate liability for such use shall not exceed USD $100.

This Section 10 does not apply to, and shall not be construed to limit, waive, or cap:

  • Any liability that cannot be limited or waived under applicable law; or
  • Any liability for fraud, intentional misrepresentation, willful misconduct, or gross negligence.

11. Indemnification

You agree to indemnify and hold harmless Belief Systems, its members, managers, officers, employees, and agents from any claims, damages, losses, or expenses (including reasonable attorneys' fees) arising from your use of the Services or violation of these Terms. This Section 11 does not require indemnification for any loss to the extent caused by Belief Systems' own fraud, willful misconduct, or gross negligence.

12. Arbitration; Class Action Waiver

Any dispute arising out of or relating to these Terms or the Services shall be resolved by binding arbitration administered by the American Arbitration Association in Portland, Oregon. You waive any right to participate in a class action or representative proceeding.

This Section 12 does not waive, and shall not be construed to waive, any right or remedy that cannot be waived under applicable law.

13. Governing Law

These Terms are governed by the laws of the State of Oregon, without regard to conflict-of-laws principles.

14. Contact

For questions regarding these Terms:

True Craft Ventures LLC d/b/a Belief Systems Email: contact@beliefsystems.xyz