Terms of Service

Effective Date: March 24, 2026
Last Updated: March 24, 2026
Previous Version: January 17, 2026

These Terms of Service ("Terms") govern your access to and use of the services offered by Sigma5C Corp ("Sigma5C," "we," "us," or "our"), including the Sigma5C platform, the Sigma5C Model Observatory, our applications, APIs, software, tools, documentation, 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 use the Services.

If you are using the Services on behalf of an organization, you represent that you have authority to bind that organization, and "you" refers to that organization.

1. Definitions

"Sigma5C," "we," "us," or "our" means Sigma5C Corp, a Delaware C Corp.
"User" means an individual who accesses or uses the Services.
"Customer" means an organization or individual that has a paid account with us.
"Customer Content" means any data, prompts, text, files, images, audio, video, code, or other materials submitted to the Services by you.
"Output" means content generated by the Services in response to Customer Content.
"AI Models" means machine-learning or artificial-intelligence systems used to generate Outputs.
"Observatory" means the Sigma5C Model Observatory, a service that publishes observational data about AI model behavior under defined conditions.
"Observation Data" means the data, metrics, tier classifications, and analysis produced by the Observatory, including model behavior measurements, condition reports, and longitudinal studies.
"Subscription Plan" means a paid tier of access to the Services, as described in Section 8.
"API Access" means programmatic access to the Services through published application programming interfaces.
"Third-Party AI Providers" means external AI model providers through which Sigma5C may route requests, including but not limited to providers accessible via OpenRouter and direct API integrations.
"Documentation" means user guides, technical docs, API references, and policies we publish.
"Usage Data" means telemetry, logs, and analytics derived from use of the Services, including API call volumes, response times, and feature utilization.

2. Eligibility and Account Registration

2.1 Eligibility

You must be at least 18 years old (or the age of majority in your jurisdiction) to use the Services.

2.2 Account Responsibility

You are responsible for:

Providing accurate account information
Maintaining the confidentiality of credentials and API keys
All activity that occurs under your account

You must notify us promptly of any unauthorized access or security breach at security@sigma5c.com.

3. Scope of Services

Sigma5C provides the following categories of services:

3.1 Sigma5C Model Observatory

The Observatory is an independent research and observability service that publishes data about AI model behavior under defined conditions. The Observatory includes:

Free Public Access: Browse observation summaries, tier classifications, and selected research findings at no cost. No account required.
Paid API Access: Programmatic access to detailed Observation Data, historical records, model comparisons, and data exports via authenticated API. Requires a Subscription Plan (see Section 8).

Observatory-specific terms are detailed in Section 4.

3.2 Data Marketplace and AI Brain

Access to curated datasets, AI-powered data processing, and intelligent retrieval services. These services include:

Access to 500+ curated datasets
AI Brain multi-provider orchestration
MCP (Model Context Protocol) servers
Document ingestion and retrieval
Conversational and agent-based AI

3.3 Developer Tools and APIs

Programmatic access to Sigma5C services, including:

RESTful APIs with published documentation
API key management and usage tracking
Webhook integrations

3.4 Enterprise Services

Custom solutions for organizations, including dedicated infrastructure, white-label options, and custom integrations. Enterprise services are governed by separate order forms that supplement these Terms.

We may modify, add, or remove features at any time. Material changes to paid features will be communicated with reasonable notice.

4. Observatory Terms

4.1 Nature of Observation Data

Important: Observation Data reflects AI model behavior under specific, defined conditions at the time of observation. Observation Data is not a guarantee of future model behavior, an endorsement or recommendation of any model, or a comprehensive assessment of model capabilities. Model behavior may vary based on hardware, software versions, network conditions, provider-side updates, prompt content, and other factors. You must independently evaluate any model before making deployment or purchasing decisions.

4.2 Free Public Observatory

The free public Observatory is provided for informational and research purposes. Free access is subject to:

Fair use: automated scraping or systematic downloading of Observatory content is prohibited
Attribution: if you cite or republish Observatory findings, you must credit "Sigma5C Model Observatory" as the source
No redistribution: you may not create competing data products based solely on scraped Observatory content

4.3 Paid Observatory API

Paid API access to Observation Data is governed by the Subscription Plan you select (see Section 8) and the API usage terms in Section 7. In addition:

You may use retrieved Observation Data for internal analysis, product development, and derived works
You may publish analyses derived from Observation Data with attribution to "Sigma5C Model Observatory"
You may not resell raw Observation Data feeds or sublicense API access to third parties
You may not use Observation Data to construct a substantially similar competing observatory service

4.4 Research Independence

The Observatory operates as an independent research service. Observation methodology, conditions, and results are not influenced by model providers, advertisers, or commercial relationships.

4.5 Observation Data Ownership

Sigma5C retains all rights to Observation Data, including the methodologies, scoring frameworks, tier classifications, and analytical outputs produced by the Observatory. The license granted to you under your Subscription Plan is limited to the uses described in Sections 4.2 and 4.3.

5. Customer Content and Output

5.1 Ownership

You retain ownership of Customer Content.
Subject to these Terms, you own the Outputs generated for you through the Data Marketplace and AI Brain services.
Observation Data is owned by Sigma5C (see Section 4.5).

5.2 License to Sigma5C

You grant Sigma5C a limited, non-exclusive, worldwide license to process Customer Content solely to:

Provide and operate the Services
Maintain security and reliability
Comply with legal obligations

5.3 AI Training and Improvement

      AI Training Policy: Sigma5C does not use Customer Content to train or improve AI models unless you explicitly opt in through account settings. We may use aggregated, de-identified Usage Data to improve system performance and reliability. Observation Data generated by the Observatory is produced by Sigma5C and is not derived from Customer Content.
    

5.4 Output Limitations

Important: Outputs are generated probabilistically and may be inaccurate, incomplete, or outdated. Outputs should not be relied upon as professional, legal, medical, or financial advice. You are responsible for reviewing and validating all Outputs before use. AI model behavior is non-deterministic; the same input may produce different outputs at different times.

6. Acceptable Use Policy

You agree not to use the Services to:

Violate any law or regulation
Infringe intellectual property or privacy rights
Generate or distribute malware or exploits
Engage in fraud, deception, or impersonation
Produce content that is unlawful, violent, or abusive
Attempt to reverse engineer, extract, or clone models
Bypass rate limits, safeguards, or access controls
Use Outputs to build or train competing AI systems without authorization
Generate content that exploits or harms minors
Conduct unauthorized security testing
Systematically scrape, harvest, or bulk-download data beyond your Subscription Plan limits
Misrepresent Observation Data, attribute fabricated findings to Sigma5C, or remove required attribution

We may suspend or terminate access for violations, with notice where practicable. Repeated or severe violations may result in immediate suspension without prior notice.

7. API and Developer Usage

7.1 General API Terms

If you use Sigma5C APIs:

You must comply with published rate limits and technical requirements for your Subscription Plan
You may not resell or sublicense API access to third parties
You may cache API responses for reasonable periods consistent with normal application operation, unless otherwise specified
You are solely responsible for securing API keys; compromised keys should be rotated immediately
You must include appropriate attribution where required (see Section 4)

7.2 Rate Limits and Fair Use

Each Subscription Plan includes defined rate limits. If you exceed your plan's limits:

Excess requests will receive HTTP 429 responses
Sustained excessive usage may trigger a temporary cooldown period
Patterns of abuse (e.g., distributed circumvention of rate limits) may result in suspension

We reserve the right to adjust rate limits with 30 days' notice.

7.3 API Versioning and Changes

We will provide at least 30 days' notice before deprecating an API version
Breaking changes will be introduced in new API versions, not applied retroactively to existing versions
Bug fixes and security patches may be applied to existing versions without notice

7.4 Data Usage Rights for API Customers

Data retrieved through the API may be used as follows:

Use	Permitted
Internal analysis and reporting	Yes
Building products that incorporate data	Yes, with attribution
Publishing derived analyses	Yes, with attribution
Caching for reasonable application use	Yes
Reselling raw data feeds	No
Sublicensing API access	No
Creating a competing observatory from scraped data	No

8. Subscription Plans, Fees, and Billing

8.1 Subscription Plans

Sigma5C offers multiple subscription tiers across its service lines. Current plans and pricing are published on our website and may be updated from time to time. Your selected plan determines your rate limits, feature access, and support level.

8.2 Fees

Subscription fees are billed monthly or annually in advance, as selected at signup
Annual plans offer a discounted rate and are billed as a single payment at the start of each annual period
Usage-based overage fees, if applicable, are billed monthly in arrears
All prices are in US dollars unless otherwise stated

8.3 Payment Processing

Payments are processed by Stripe, Inc. By providing payment information, you also agree to Stripe's Terms of Service. Sigma5C does not store credit card numbers directly.

8.4 Plan Changes

Upgrades take effect immediately, with prorated charges for the remainder of the billing period
Downgrades take effect at the start of the next billing period
If you downgrade, you may lose access to features or rate limits associated with your previous plan

8.5 Refund Policy

Monthly subscriptions: no refunds for partial months
Annual subscriptions: prorated refund available within the first 30 days if you have not exceeded 10% of your plan's monthly API allocation
Refunds for service outages are addressed through SLA credits (see Section 8.7)

8.6 Taxes

You are responsible for all applicable taxes, excluding taxes on Sigma5C's net income. If we are required to collect taxes, they will be added to your invoice.

8.7 Service Level

Sigma5C targets high availability for all paid services. Specific uptime commitments and service-level credits, where applicable, are described in the service documentation for your Subscription Plan. Enterprise customers may negotiate custom SLAs as part of their order form.

9. Confidentiality

Each party agrees to protect the other's confidential information and use it only to fulfill obligations under these Terms.

Confidential information does not include information that is:

Publicly available through no fault of the receiving party
Independently developed without use of confidential information
Rightfully received from a third party without restriction

10. Security

Sigma5C implements administrative, technical, and organizational measures designed to protect Customer Content and the integrity of the Services, including:

Encryption in transit (TLS 1.2+) and at rest
Multi-factor authentication and role-based access controls
API key hashing (HMAC-SHA256) and secure credential storage via HashiCorp Vault
Regular security assessments and code reviews
Incident response procedures
Audit logging of administrative and data-access events

For more details, see our Security page. No system is perfectly secure, and you acknowledge residual risk.

11. Third-Party AI Providers and Services

11.1 Third-Party AI Providers

Certain Services route requests to or through Third-Party AI Providers to process Customer Content and generate Outputs. When you use these Services:

Your Customer Content may be transmitted to Third-Party AI Providers for processing
You agree to comply with the usage policies and restrictions of the applicable Third-Party AI Providers
Output quality, availability, and behavior depend in part on these Third-Party AI Providers and may change without notice from Sigma5C
Sigma5C is not responsible for the actions, policies, outages, or content filtering decisions of Third-Party AI Providers

A current list of Third-Party AI Providers and their compliance status is maintained at Third-Party Providers.

11.2 Provider-Specific Restrictions

Some Third-Party AI Providers impose restrictions on how their models may be used (e.g., prohibitions on generating certain categories of content). These restrictions apply to your use of the Services when routed through those providers, and it is your responsibility to be aware of and comply with them. Sigma5C makes reasonable efforts to document known restrictions but does not guarantee completeness.

11.3 Other Third-Party Services

The Services may integrate with other third-party platforms (e.g., payment processors, email services, analytics). Your use of those services is governed by their respective terms.

12. Intellectual Property

12.1 Sigma5C IP

Sigma5C retains all rights to:

The Services, including the Observatory and its Observation Data
Observation methodologies, scoring frameworks, and analytical outputs
Software, architecture, and Documentation
Trademarks, logos, and branding

Except for the rights expressly granted, no license is implied.

12.2 Feedback

If you provide feedback or suggestions, Sigma5C may use them without restriction or obligation.

13. Suspension and Termination

13.1 By You

You may cancel your Subscription Plan at any time through your account settings. Cancellation takes effect at the end of the current billing period. Termination does not relieve payment obligations incurred before termination.

13.2 By Sigma5C

We may suspend or terminate access if:

You violate these Terms or the Acceptable Use Policy
Your use poses a security, legal, or operational risk to the Services or other users
Your account is delinquent on payment for more than 15 days
Required by law or by a Third-Party AI Provider's terms

Where practicable, we will provide notice and an opportunity to cure before termination.

13.3 Effect of Termination

Upon termination:

Your right to use the Services ends immediately
API keys associated with your account are revoked
We will retain or delete Customer Content per our Privacy Policy
You may request export of your Customer Content for up to 30 days after termination
Provisions that should survive termination (including Sections 5.3, 9, 12, 14, 15, 16, and 17) remain in effect

14. Disclaimers

THE SERVICES, OUTPUTS, AND OBSERVATION DATA ARE PROVIDED "AS IS" AND "AS AVAILABLE." SIGMA5C DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO: MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, AND ACCURACY, COMPLETENESS, OR RELIABILITY OF OUTPUTS OR OBSERVATION DATA. SIGMA5C DOES NOT WARRANT THAT THE SERVICES WILL BE UNINTERRUPTED, ERROR-FREE, OR FREE OF HARMFUL COMPONENTS.

OBSERVATION DATA REFLECTS MODEL BEHAVIOR UNDER SPECIFIC CONDITIONS AT THE TIME OF OBSERVATION AND DOES NOT CONSTITUTE AN ENDORSEMENT, RECOMMENDATION, OR GUARANTEE OF ANY AI MODEL OR PROVIDER.

15. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW: (A) SIGMA5C WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, INCLUDING BUT NOT LIMITED TO LOSS OF PROFITS, DATA, BUSINESS OPPORTUNITIES, OR GOODWILL; AND (B) SIGMA5C'S TOTAL AGGREGATE LIABILITY ARISING OUT OF OR RELATED TO THESE TERMS WILL NOT EXCEED THE GREATER OF (I) THE AMOUNTS PAID BY YOU TO SIGMA5C IN THE 12 MONTHS PRECEDING THE CLAIM, OR (II) ONE HUNDRED US DOLLARS ($100).

16. Indemnification

You agree to indemnify, defend, and hold harmless Sigma5C, its officers, directors, employees, and agents from any claims, damages, losses, or expenses (including reasonable attorneys' fees) arising out of:

Your Customer Content
Your use of the Services or Observation Data
Your violation of these Terms, the Acceptable Use Policy, or applicable law
Your violation of Third-Party AI Provider terms through use of the Services

17. Governing Law and Dispute Resolution

These Terms are governed by the laws of the State of Delaware, excluding conflict-of-laws principles.

Any dispute will be resolved exclusively in the state or federal courts located in Delaware, unless otherwise agreed in writing. Both parties consent to personal jurisdiction in those courts.

18. Changes to These Terms

We may update these Terms from time to time. When we make material changes:

We will update the "Last Updated" date at the top of this page
We will notify you via email or through the Services at least 30 days before the changes take effect
The previous version will remain accessible via the "Previous Version" link

Continued use of the Services after the effective date of updated Terms constitutes acceptance. If you do not agree with the changes, you may cancel your Subscription Plan before the new terms take effect.

19. General Provisions

Entire Agreement: These Terms, together with the Privacy Policy, Acceptable Use Policy, and any applicable order forms, constitute the entire agreement between you and Sigma5C regarding the Services.
Severability: If any provision is found unenforceable, the remaining provisions remain in full effect.
Waiver: Failure to enforce a provision does not waive our right to enforce it later.
Assignment: You may not assign your rights under these Terms without our prior written consent. Sigma5C may assign these Terms in connection with a merger, acquisition, or sale of substantially all of its assets.
Force Majeure: Neither party is liable for delays or failures caused by events beyond reasonable control, including natural disasters, pandemics, government actions, internet outages, or Third-Party AI Provider disruptions.
Notices: Notices to you will be sent to the email address on your account. Notices to Sigma5C should be sent to legal@sigma5c.com.

20. Contact Information

Sigma5C Corp
Delaware C Corp
Email: info@sigma5c.com
Legal: legal@sigma5c.com
Security: security@sigma5c.com
Website: https://sigma5c.com