Models

Your organization's Models page lists every model your organization can use. Owners and admins can change each model's settings; other members can view them. See Pricing for the models Radius serves and their prices.

Model types

There are three types of models:

• Built-in models are served and billed by Radius. You can't create or delete them, but you can change their settings or disable them.
• Virtual models give your team a model name to select in Pi, such as balanced, while your organization decides which model actually answers. You can switch that model for everyone without anyone changing their setup, or use a routing rule to pick a different model per request, such as a cheaper model for simple questions and a stronger one for hard ones. Each request to a Virtual model goes through its routing rule, which picks the Built-in or BYOK model that answers it. Radius provides cheap, balanced, and precise, and you can create your own. See Virtual models.
• BYOK models are models you add yourself. They run through your organization's own provider keys. To enable BYOK for your organization, contact feedback@earendil.com.

What you can configure

Every model has these settings:

• Availability makes a model available to all members, only to selected groups, or to no one. It only controls who can select a model directly: a Virtual model can still use a Built-in or BYOK model that is disabled or limited to other groups. For example, disable deepseek-v4.1-flash so people can only use it through cheap.
• Maximum thinking level caps the thinking level of each request. Requests that ask for more are lowered to the cap. When a cap is set and the model that answers doesn't support the resulting level, Radius lowers it to the next level the model supports, or turns thinking off if there is none.
• Rewrite rules change the conversation before the model sees it. For example, they can compact long tool output to save tokens, or add the same instructions to the system prompt for everyone in your organization. You choose which rules each model uses; new models use none.

Virtual models also have a routing rule, which picks the model that handles each request.

You can delete Virtual and BYOK models you created. Resetting cheap, balanced, or precise restores the settings Radius provides.

How a request uses these settings

When someone sends a request to a model, Radius:

1. Checks that the requester may use the model they selected.
2. Lowers the requested thinking level to the model's maximum, if one is set.
3. Runs the model's selected rewrite rules, in the order shown on the Rewrite rules page.
4. For a Virtual model, runs its routing rule to pick a Built-in or BYOK model.
5. Sends the request to the picked model.

Only the requested model's settings apply. If a Virtual model picks a Built-in model, the Built-in model's own thinking level and rewrite rules are not applied.

Manage models with an agent

Instead of using the Models page, you can ask Pi to manage models through the Radius MCP server. Ask Pi to read the current models before changing them. Models are managed with the models.list, models.upsert, and models.delete operations.

Virtual models

A Virtual model is a model name your team selects in Pi, such as balanced, while your organization decides which model actually answers. Use Virtual models to:

• Change models without changing anyone's setup. Point balanced at a newer model, and everyone who uses balanced gets the new model on their next message.
• Pick a model for each request. A custom routing rule can look at the request and choose a model, such as a cheaper model for short questions and a stronger one for large codebases.
• Bundle settings under one name. A Virtual model has its own availability, maximum thinking level, and rewrite rules. For example, a review model could add your team's review guidelines to the system prompt.

Each request to a Virtual model goes through its routing rule, which picks the Built-in or BYOK model that answers it. See Model types for how they fit together.

Virtual models have no price of their own. Each request is billed at the price of the model that answered it. In analytics, Requested model shows the model people selected, which can be a Built-in, Virtual, or BYOK model, and Physical model shows the model that answered.

Default Virtual models from Radius

Every organization starts with three Virtual models:

• cheap for routine tasks where cost matters most.
• balanced for everyday work.
• precise for complex tasks where quality matters most.

Each sends every request to one model chosen by Radius. Open it on the Models page to see which one. Radius may change these choices as better models become available.

You can change their settings like any other Virtual model. Once you do, your settings replace the ones Radius provides, so later Radius changes no longer apply to that model. Select Reset to default to return to the Radius settings.

Create a Virtual model

Owners and admins can create Virtual models:

1. On the Models page, select New Virtual Model.
2. Enter an ID. This is the name people select in Pi. Use lowercase letters and digits, starting with a letter, up to 64 characters. It can't match the ID of another model in your organization. The API is less strict: models.upsert also accepts hyphens and IDs that start with a digit, and an ID that already exists updates that model instead of creating a new one.
3. Choose a routing rule:
   • Static sends every request to one model you select.
   • A custom routing rule picks a model for each request. Its settings appear after you select it. See Routing rules to write one.
4. Set availability, maximum thinking level, and rewrite rules. See What you can configure.
5. Select Create virtual model.

You can also ask Pi to create one for you. Set up Pi as described in Manage models with an agent, then describe what you want, for example: "Help me create a Radius virtual model that uses a fixed model but always appends a fixed instruction to the system prompt."

Change, rename, or delete

Changes apply to new messages, usually within moments and at most within an hour. A reply that is already in progress usually keeps the model it started with. See When routing rules run.

Renaming a Virtual model changes the name people select in Pi. Anyone using the old name has to switch to the new one. If you rename cheap, balanced, or precise, the original name is disabled.

You can delete Virtual models your organization created. You can't delete cheap, balanced, or precise, but you can disable them by setting their availability to Disabled.