Model policy

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. Define the policy in builder.configuration.agent.models.

Quickstart

src/mastra/index.ts

import { MastraEditor } from '@mastra/editor'

new MastraEditor({
  builder: {
    enabled: true,
    configuration: {
      agent: {
        models: {
          allowed: [
            { provider: 'openai', modelId: 'gpt-5.6' },
            { provider: 'anthropic', modelId: 'claude-sonnet-5-5' },
          ],
        },
      },
    },
  },
})

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

Validation rules

Mastra validates the model policy at server boot and throws an error for invalid configurations.

• When allowed is empty or omitted, every registered model is available.
• When allowed is non-empty, default (if set) must satisfy the allowlist. If default fails this check, Mastra throws an error at startup. Add the model to allowed or change default.
• To hide the end-user model picker, set features.agent.model: false in AgentBuilderOptions. 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 reference for every admin-writable field and validation rules.