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The Major MCP server exposes Major itself as Model Context Protocol tools. Connect an MCP client and your AI assistant can list and create apps, agents, skills, and workflows, start sandboxes and edit their files, query your connectors, run agents and workflows, and deploy - from the client you already use. It gives your client the same capabilities as the Platform Agent in the web app.

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Example requests

  • “List the apps I can edit in Major.”
  • “Create an app that shows open support tickets from our Postgres database, then deploy it.”
  • “Add a status filter to the dashboard in my ops-dashboard app.”
  • “Build an agent that summarizes yesterday’s Slack messages in #sales.”
  • “Run the weekly-report workflow with the input { \"region\": \"EMEA\" }.”
  • “How many customers signed up last week?”

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Connect

The recommended way to connect is the Major plugin. It configures the MCP server and installs the Major skills in one step. See the Quickstart for install steps for each client.
To configure the server by hand, use: The first time your client connects, a browser tab opens to Major. Sign in and click Allow to grant the client access to your organization. The client then stores the token and connects without prompting again.
The access token is tied to one organization. To work in a different organization, reconnect the server and approve access for that organization.

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Skills in the plugin

The plugin also installs skills that teach your assistant how to build on Major. The assistant loads them on demand: The Platform Agent uses the same skills, so your client and the web app build things the same way.

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What it can do

Tools that need secrets or credentials, such as request_resource_setup and set_app_env_variables, never take them from your assistant. They return a link that you open in Major to enter the values yourself.

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How it works

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Sandboxes

Apps, agents, skills, and workflows are all edited on a remote sandbox. Your assistant finds what to edit with list, starts its sandbox with start_sandbox (or create for something new), and then edits through the sandbox_* tools. Every sandbox call names its target: an app’s slug, or an agent, skill, or workflow id. Several sandboxes can run at once. You can watch every sandbox your client starts at app.major.build/sandboxes, with one tab per sandbox, including an app’s live preview. A sandbox is held by one person at a time. If someone else is editing the same item, start_sandbox reports that it is locked.

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Saving, publishing, and deploying

Inside a sandbox, sandbox_bash runs the Major CLI in the workspace root: An app’s first deploy needs major publish --slug <slug> to choose its URL. See the CLI for the full command set.

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Connectors

Your assistant does not load a separate tool for every connector. It describes what it needs to search_resource_tool_catalog (for example, “read-only SQL against Postgres”), gets back matching tools with their input schemas, and runs one with execute_resource_tool. See Connectors.

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Permissions

The MCP server acts as you:
  • Scoped to your organization. Every call runs in the organization you approved when you connected.
  • Scoped to your roles. list returns only what you can access, and each tool checks your access to the item it touches. Creating things, starting sandboxes, running agents and workflows, and connector setup require permission to build in the organization. Members without it see only the connector, deployed-app, and listing tools. See Members & roles.
  • Approvals happen in your client. Your personal tool permissions apply to Platform Agent chats in the web app, not to MCP clients. Use your client’s own tool approval settings to control what runs without asking.

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Next steps

Quickstart

Install the Major plugin in your client.

Platform Agent

The same capabilities, built into the web app.

CLI

Build on Major from your own terminal.