The builder is an ordinary remote MCP server over Streamable HTTP. Any client that supports remote connectors can use it. This page describes the connection and the tools as they will ship; access is coming soon and the connector URL is sent to you when it opens.
Adding the connector
- ChatGPT. Settings, Connectors, Advanced, enable Developer mode, then Create a connector with the URL you received. In the first release there is no OAuth step; your access is bound to the URL.
- Claude (web and desktop). Settings, Connectors, Add custom connector, paste the URL. No OAuth client is needed in the first release.
- Claude Code and other clients. Add it as a remote HTTP MCP server with the same URL.
Once connected, ask the assistant to list the builder's tools. You should see the eight tools below. For background on connectors in general, see connecting ChatGPT and connecting Claude.
The tools
| Tool | What it does |
| --- | --- |
| list_sites | Your sites, with versions, repository and preview URL. |
| create_site | Creates a site from its name and returns its project id. |
| describe_site | Saves the brief: objective, audience, pages, features, style, colours, acceptance criteria, constraints and what is out of scope. Replaces the previous brief. |
| plan_site | Quotes, approves and starts planning for the current brief. |
| answer_questions | Answers the planner's open questions on a job that is waiting for input. |
| build_site | Provisions the repository on first use, then quotes, approves and starts the build of the reviewed plan. |
| site_status | Project context, the current plan, the active job with its next action, and your credit balance. |
| site_events | Chronological events with a cursor, for a full audit trail of the project. |
Every tool that spends credits returns the amount charged and the balance after the charge. Errors come back as readable tool errors, with a stable code, so the assistant can explain them instead of guessing.
A first conversation
A useful first session is short and specific.
Create a site called "Velo Zürich". It is a bicycle repair shop. Objective: win repair bookings. Audience: commuters and families. Pages: home, services, contact. Features: a contact form. Style: warm and practical, lots of white space, colours deep teal and white. Done means every page renders without console errors and the form delivers to our inbox.
The assistant calls create_site, then describe_site with those fields, then plan_site. The planner usually comes back with two or three questions: opening hours, whether prices should be listed, which email receives the form. Answer them in plain language; the assistant calls answer_questions. When the plan is ready, read it. It names the pages, the data entities, the images it will generate, and the acceptance checks. Amend anything you disagree with, then say "build it". The assistant calls build_site, polls site_status until the preview is ready, and gives you the URL.
What the assistant should not do
The builder is designed so the assistant cannot skip your decisions. It cannot start a build before a plan exists, cannot spend credits without a quote, and cannot deploy to production without an explicit instruction. If a tool refuses, the error says which step is missing.