Design with your AI
Writing a 2by model by hand takes practice. An AI assistant you already use, such as Claude or ChatGPT, can write it for you from a conversation, a sketch or a photo of your plans. Give it the guide below, and it knows everything 2by reads.
1. Give your assistant the guide
Start a new chat and paste this in:
Read the 2by model guide at https://2by.app/ai/guide.md and follow it exactly. Help me write a 2by model for my project. Interview me first, one question at a time, and confirm the footprint and post layout with me before you write any YAML.
If your assistant can’t open web pages, download the guide and attach the file to the chat instead.
2. Describe your project
It will ask about the size, the foundation, the posts and beams, the joists, any walls and roof, and the loads. Loads and soil bearing come from your building department. Your assistant should ask you for them and never guess them.
3. Open the file in 2by
Save what it writes as a .yaml file, then open it:
- signed in: My designs → New design → Choose a .yaml file;
- or in the demo: IMPORT.
4. Send back what 2by found
2by checks the model and lists what it found under FINDINGS. Press COPY FOR AI there and paste the result into the same chat. Your assistant fixes the file and gives you a new one. Repeat until there are no errors or warnings left, or only the ones you have decided to accept.
Let your assistant check its own work
If your assistant can use connectors (MCP), such as Claude or ChatGPT with custom connectors, Claude Code or Cursor, add one with this address:
https://2by.app/mcp
It needs no sign-in. Your assistant can then read the guide and run 2by’s checks itself, show you a picture of the plan and the 3D view, and hand you a file that already passes. The model text is checked and then discarded; nothing is stored.
Or let it save straight to My designs
With a 2by account, use this address instead. The first time, your assistant sends you to 2by to sign in and choose Allow:
https://2by.app/mcp/account
It does everything the address above does, and when you say so, it saves the design to My designs and gives you the link: no file to save or import. Designs it saves are labelled with its name. It cannot delete or change your designs. End the connection any time under Connected assistants on My designs; signing out ends it too.
Examples
The guide points your assistant at these. You can open them in 2by too.
- small-deck.yaml: the smallest complete model: an 8' × 8' deck on four posts
- garden-shed.yaml: a shed on deck blocks, with walls and a gable roof
- tiered-deck.yaml: a deck on three levels
- shop-loft.yaml: a post-and-beam loft with a stair
What 2by is not
2by is a planning and takeoff tool. A model that passes its checks is not an engineered or approved design, and neither is anything your assistant tells you about it. Check what you build with your building department.