# Model policy

> **Note:** The Agent Builder is part of the Mastra Enterprise Edition. Production deployments require a valid EE license. [Contact sales](https://mastra.ai/contact) for more information.

The model policy controls which providers and models Builder-created agents can use, which model is selected by default, and whether end users can change it. The policy lives at `builder.configuration.agent.models`.

## Quickstart

```typescript
import { MastraEditor } from '@mastra/editor'

new MastraEditor({
  builder: {
    enabled: true,
    configuration: {
      agent: {
        models: {
          allowed: [
            { provider: 'openai', modelId: 'gpt-5.4-mini' },
            { provider: 'openai', modelId: 'gpt-5.4' },
            { provider: 'anthropic', modelId: 'claude-opus-4-7' },
          ],
        },
      },
    },
  },
})
```

This restricts the Builder's model picker to two OpenAI models and one Anthropic model. End users choose one when creating an agent.

## Validation rules

Mastra validates the model policy at server boot. Violations are surfaced as warnings through `getModelPolicyWarnings()`.

- When `allowed` is empty or omitted, every registered model is available.
- When `allowed` is non-empty, `default` (if set) must satisfy the allowlist. A `default` that fails this check is dropped and surfaced as a warning.
- To hide the end-user model picker, set `features.agent.model: false` in [AgentBuilderOptions](https://mastra.ai/reference/editor/agent-builder/agent-builder-options). When the picker is hidden, provide a `default` so new agents resolve a model.

Registered providers (`provider: 'openai'`, `provider: 'anthropic'`, and so on) can omit `modelId` to allow every model from that provider.

See the [`builder.configuration.agent.models`](https://mastra.ai/reference/editor/agent-builder/builder-models) reference for every admin-writable field and validation rules.

## Related

- [Configuration](https://mastra.ai/docs/agent-builder/configuration) — wire the model policy into the broader Builder config.
- [`builder.configuration.agent.models`](https://mastra.ai/reference/editor/agent-builder/builder-models) — full property list.
- [Provider registry](https://github.com/mastra-ai/mastra/blob/main/packages/core/src/llm/model/provider-registry.json) — every model ID Mastra recognizes out of the box.