Agent Builder overview

note

The Agent Builder is part of the Mastra Enterprise Edition. Production deployments require a valid EE license. Contact sales for more information.

The Agent Builder lets you build, configure, and operate Mastra agents all within the UI. It runs inside your Mastra server, persists everything to Mastra.storage, and supports multi-tenant agent workflows with RBAC and channel integrations.

• Configuration: Toggle UI sections and pin admin-controlled defaults for every new agent.
• Model policy: Restrict which providers and models the Builder exposes, and pin a default.
• Memory: Configure the default memory shape for every Builder-created agent.
• Access control: Gate the Builder behind Mastra RBAC roles and permissions.
• Channels: Connect Builder-created agents to Slack and other channels.
• Skill registries: Browse and install community skills from opt-in registries.
• Deploying: Swap local primitives for cloud-backed storage, filesystems, and sandboxes.

For building agents entirely in code, see the Agents overview. For editing code-defined agents through Studio, see the Editor overview.

Get started

Install @mastra/editor alongside a storage adapter:

npm

npm install @mastra/editor @mastra/libsql

pnpm

pnpm add @mastra/editor @mastra/libsql

Yarn

yarn add @mastra/editor @mastra/libsql

Bun

bun add @mastra/editor @mastra/libsql

Wire the Agent Builder onto a Mastra instance:

src/mastra/index.ts

import { Mastra } from '@mastra/core/mastra'
import { MastraEditor } from '@mastra/editor'
import { createBuilderAgent } from '@mastra/editor/ee'
import { LibSQLStore } from '@mastra/libsql'

export const mastra = new Mastra({
  storage: new LibSQLStore({ url: 'file:./mastra.db' }),
  agents: { builderAgent: createBuilderAgent() },
  editor: new MastraEditor({
    builder: {
      enabled: true,
      configuration: {
        agent: {
          memory: { observationalMemory: true },
        },
      },
    },
  }),
})

Start the dev server:

npx mastra dev

The Agent Builder is mounted at http://localhost:4111/agent-builder.

Prerequisites

The Agent Builder requires:

• Storage: An @mastra/core storage adapter on the Mastra instance. Agents, memory, and workspace state all persist through Mastra.storage.
• The Builder agent: Register a Builder agent created with the createBuilderAgent() factory from @mastra/editor/ee on Mastra.agents. The chat-based editor invokes it through the same Mastra.getAgent(id) lookup as any other agent. Without this registration, the chat-based editor returns 404.
• OPENAI_API_KEY: The Builder agent created by createBuilderAgent() runs on an OpenAI model, so an OPENAI_API_KEY environment variable is required.

Disabling the Builder

Set enabled: false to keep the config in place but turn the surface off:

src/mastra/index.ts

new MastraEditor({
  builder: {
    enabled: false,
  },
})

Omitting the builder field has the same effect.