Radius Alpha – Terms of Service

2 November 2026

These Terms of Service ("Terms") are a legally binding agreement between you and Earendil Works Co. ("Earendil," "we," "us" or "our") about your use of Radius, including our website at radius.earendil.com and our related applications, APIs and services (together, "Radius" or the "Service"). By accepting these Terms when you sign up or when we ask you to, or by using the Service, you agree to them.

1. About Radius

1.1 What Radius is. Radius is an experimental, pre-release AI model gateway and agent service layer, hosted and provided by Earendil. It provides access to multiple artificial intelligence models ("Models"), budget controls and token-usage visibility, and can be used to power any agent or AI application. Radius also offers features such as web search and artifacts, and other features may be added.

1.2 Inputs, Outputs and User Content. When you use a Model through Radius, Radius sends your request to that Model and returns its response to you. Radius does not run the Models itself. "Inputs" are the material you submit to the Service, such as prompts, text, code, files and images. "Outputs" are the material a Model returns through the Service in response to your Inputs. Inputs and Outputs together are "User Content."

1.3 Alpha service. Radius is an early, pre-release service. It may contain errors, and it may change, be interrupted or be discontinued at any time. You may use it to power applications that have their own end-users, but it is not yet a stable service, so do not rely on it for safety-critical functions or anything that requires guaranteed accuracy, availability, security or continuity. No service level, support, capacity, continued access or launch commitment applies.

1.4 Acceptable use. You may use the Service to build, test and power AI agents and applications, including applications you offer to your own end users, and to evaluate which Models to use in them. If your applications have their own end-users, you are responsible for their use of the Service and must require them to follow Section 4, which sets out prohibited use.

2. Your account and eligibility

2.1 Eligibility. You must be at least 18 years old and able to form a binding contract to use the Service. If you use the Service for an organization, you confirm that you are authorized to accept these Terms on its behalf, and "you" includes that organization.

2.2 Your account. You need an account to use the Service. The information linked to your account, such as your email address, sign-in details, organization membership, API keys, billing details and usage records, is your "Account Information." You are responsible for your account, for the members and users you give access to, and for all activity and charges under your account.

2.3 Credits and payment. Access to the Service, or to certain features of the Service, may require you to pay fees for pre-paid credits that are linked to your account, along with payment processing fees and transaction fees. Credits have no cash value, cannot be transferred to another account or sold on, and are non-refundable except where the law requires or these Terms say otherwise. Credits expire one year after purchase. If you turn on automatic top-up, we charge your selected amount whenever your balance reaches your selected threshold, until you turn it off. Prices are shown in the Service and may change for future usage.

2.4 API keys. Keep API keys and other credentials confidential and do not share them outside your organization. You are responsible for all usage and charges under your API keys. Tell us promptly at feedback@earendil.com if you believe a key has been compromised. We may suspend or revoke API keys to protect you, the Service or others.

3. Model Inference on Radius

3.1 How Models are served. Radius provides access to several Models, and you choose which Model to use. We use OpenRouter, Inc. ("OpenRouter") as a technology partner to route your requests to suitable companies that serve each Model ("Model Providers"). This means that when you use Models through Radius, you also agree to comply with the OpenRouter Terms of Service, as updated from time to time, and with the terms that apply to each Model selected ("Model Terms"). The list of available Models, and how data is handled for each route, is in our Model catalog.

3.2 How Radius handles User Content. Earendil does not store or retain User Content beyond the transient processing needed to handle your request, unless you choose to store content with us, for example by publishing an artifact (Section 5.5). Radius does not use User Content to train models. This applies to every request sent through Radius, including with your own provider keys if enabled (Section 3.5).

3.3 How Model Providers handle User Content. What happens to User Content at the Model Provider depends on the Model selected. Our Model catalog shows, for each Model, whether User Content may be used for training and how long it may be kept.

We select Model Providers based on their published data policies. We do not control or audit their practices and are not responsible for a Model Provider's failure to follow its terms.

3.4 Availability and suspension. Models are provided on an as-available basis, and the Models and Model Providers available through the Service may change at any time. We may suspend your access to a Model if we reasonably believe your use breaks these Terms, the OpenRouter Terms of Service or the Model Terms. OpenRouter or a Model Provider may also restrict access to a Model under its own terms, with or without notice.

3.5 Your own provider keys. Where available, you can connect your own provider keys ("BYOK"). With BYOK, Radius still sends your requests and Section 3.2 still applies, but your requests go directly to that provider under your own account, not through OpenRouter. Your agreement with that provider governs how it handles them, instead of the OpenRouter Terms of Service, the Model Terms and Section 3.3.

3.6 Web search and other features. Optional features, such as web search, may use other third-party providers under their own terms. Some features offer options with different data handling, as described in our documentation, and you are responsible for the options your organization chooses.

4. Prohibited conduct

You must not, and must not allow anyone else to, use the Service to:

5. Your content and data

5.1 Your rights. You keep your rights in your Inputs. As between you and Earendil, we assign to you any rights we have in Outputs. Outputs may not be unique, and others may receive similar Outputs. You confirm that you have the rights and permissions needed to submit your Inputs and use them with the Service.

5.2 Our use of User Content. You allow us to process and transmit User Content, including through OpenRouter and to Model Providers, only as needed to provide the Service, and to let OpenRouter categorize Inputs, without storing them, to produce anonymized aggregate statistics.

5.3 Sensitive data. Do not submit government identification numbers, payment card or bank account numbers, passwords, or health, biometric, genetic or other special categories of personal data. Avoid including other personal, confidential or regulated data, or live credentials or secrets, in your Inputs or artifacts.

5.4 Account Information. We use Account Information to provide, secure and bill for the Service. We share it with service providers that help us run the Service, where needed to prevent misuse of the Service, where the law requires and in the other cases described in our Privacy Policy.

5.5 Artifacts. When you publish an artifact, we store it until you delete it or it expires under your organization's settings. Artifacts may be private, visible to your organization, or accessible to anyone with the link, depending on their sharing settings. You are responsible for what you publish and who you share it with.

5.6 Usage data. We may use usage metadata to operate, improve and tailor the Service, including by sharing and publishing aggregated statistics that do not identify you or your organization. OpenRouter may also use usage metadata to provide and improve its service, as described in our Privacy Policy.

5.7 Privacy. Our Privacy Policy explains how we collect and use personal data. These Terms are not a data processing agreement.

6. Suspension and termination

We may limit, suspend or end your access to the Service, or to particular Models, routes or features, at any time and with or without notice. We may do so if we reasonably believe you have broken these Terms, the OpenRouter Terms of Service or any Model Terms. We may also do so if OpenRouter or a Model Provider requires it, to comply with the law, or to protect the Service, our users or others. You may stop using the Service and close your account at any time. If we permanently shut the Service down, or close your account for a reason other than breach, misuse or non-payment, we will refund your unused purchased credits, and this is your only remedy.

7. Disclaimers, liability and indemnity

Outputs are experimental and may be inaccurate, incomplete, insecure or harmful. You are responsible for reviewing them and for any code, decision, application or action based on them.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, THE SERVICE, OUTPUTS AND RELATED SERVICES ARE PROVIDED "AS IS" AND "AS AVAILABLE," WITHOUT WARRANTIES OF ANY KIND. EARENDIL DOES NOT WARRANT ACCURACY, AVAILABILITY, SECURITY OR UNINTERRUPTED OPERATION, OR ANY MODEL, OUTPUT, MODEL PROVIDER OR THIRD-PARTY SERVICE, INCLUDING OPENROUTER.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, EARENDIL WILL NOT BE LIABLE FOR INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, CONSEQUENTIAL OR PUNITIVE DAMAGES, OR FOR LOST PROFITS, REVENUE, DATA, GOODWILL, BUSINESS INTERRUPTION, DATA CORRUPTION OR SUBSTITUTE SERVICES. EARENDIL'S TOTAL AGGREGATE LIABILITY WILL NOT EXCEED THE GREATER OF $100 OR THE AMOUNT YOU PAID FOR RADIUS CREDITS DURING THE 3 MONTHS BEFORE THE EVENT GIVING RISE TO THE CLAIM. NOTHING IN THESE TERMS LIMITS LIABILITY THAT CANNOT LAWFULLY BE LIMITED OR AFFECTS MANDATORY RIGHTS AVAILABLE TO CONSUMERS.

To the extent permitted by law, you will defend, indemnify and hold harmless Earendil, its affiliates, personnel and licensors against third-party claims and reasonable costs arising from your applications and their users, User Content, unlawful use, breach of the OpenRouter Terms of Service or Model Terms, or material breach of these Terms, except to the extent caused by Earendil's violation of law.

8. General

8.1 Changes to these Terms. We may update these Terms for the future. We will post or tell you about material changes, and we may ask you to accept the updated Terms before you continue using the Service. Otherwise, using the Service after the effective date means you accept them.

8.2 Ownership and feedback. Earendil and its licensors own all rights in the Service. These Terms do not give you any rights in the Service other than the right to use it under these Terms. If you give us feedback, we may use it without restriction or obligation.

8.3 Governing law. Delaware law and courts apply, subject to mandatory consumer protections in your country of residence. If a provision of these Terms is invalid, it will be limited as needed and the rest will remain in effect. These Terms are the entire agreement between you and us about the Service.

8.4 Contact. Questions about these Terms: feedback@earendil.com.