Blueprints (experimental) — a guide for testers

Blueprints interviews you about the app you want, writes the answers up as a specification, and then has Claude Code build it from that specification step by step. It stops only for what a person must decide — approving the specification, anything that costs money, publishing — and otherwise runs to the end on its own.

Experimental. It ships in MulmoTerminal from 6.5.0, but both the screens and what they do are still changing.

  1. What you need
  2. Running it
  3. Trust a folder for the builds first
  4. Your first build: “おうち図書館” (home library)
  5. What we would like you to try
  6. When something goes wrong
  7. How to report
  8. Known limitations

What you need

  Needed
Everyone Node.js 22.13 or later, yarn, a signed-in Claude Code (claude runs), git
Only to try Firebase A Google account, a Google Cloud billing account you can attach a payment method to, the Firebase CLI (firebase), gcloud, JDK 21 or later (on macOS, brew install openjdk@21 is enough)

Start with a local build (no Firebase). It stays entirely on your machine and needs no cloud setup or spending.

Claude usage: a build starts a Claude Code session for every step, so it uses noticeably more than an ordinary chat.

Language: the packs, the examples and the questions the agents ask are in Japanese for now. The screens themselves follow MulmoTerminal’s language setting.

Running it 

npx mulmoterminal@latest

Open http://localhost:34567. If the top bar has a Blueprints button, you are ready. (npx mulmoterminal --version should say 6.5.0 or later.)

  • Only one MulmoTerminal per machine runs blueprints. Start a second one and it can show the builds but refuses any change with blueprints on this machine are run by the MulmoTerminal on port ….
  • A step’s agent does not appear in your usual grid; the Blueprints screen shows what it is doing.

Trust a folder for the builds first

The agents work with nobody watching, so Claude Code’s “Do you trust this folder?” prompt would stop them for good. A build can therefore only start inside a folder Claude Code already trusts. Do this once:

  1. Make a parent folder for your trials, e.g. mkdir ~/blueprint-trials.
  2. Run claude in it, answer yes when it asks whether to trust the folder, and quit.
  3. For each build, make an empty folder inside it, e.g. mkdir ~/blueprint-trials/library.

Do not git init the build folder. A folder that becomes a git repository no longer inherits its parent’s trust, and a later step stops. Add git after the build is done if you want it.

Your first build: “おうち図書館” (home library)

A small app that records the books in your house and who has borrowed which, built and run on your own machine.

  1. Blueprints → New build.
  2. Under Start from an example, press Use this example on おうち図書館. It fills in the base (local), the kind of system (build anything) and the answers to the questions.
  3. Enter the empty folder you made as a full path in Project folder and press Start.
  4. Once the first step has written the specification, the build stops at the specification screen. This is the part that matters most.
    • Read the specification, and look at anything under Not decided yet.
    • To change something, write it in the box underneath and send it (e.g. “let me delete a book too”). The agent revises the specification and replies.
    • When you are happy with it, press Approve.
  5. The steps then run in order. For the step in progress you see what the agent is doing and how long it has taken.
    • Has a question for you: write an answer and press Send.
    • If a step stops, read What the check reported and press Try again.
  6. Every step is done. means you are finished. The folder’s README.md says how to start the app (yarn start) and where its data lives. Start it and use it.

What we would like you to try

As much as you have time for — and tell us which ones you did.

The main path

  • Build the home library to the end, and the app it made works
  • Talk to the specification screen and see the specification change (a few rounds)
  • Build one more example: 家計簿 (household budget), チームのタスクボード (team task board) or 見積書づくり (quotes)
  • Without an example, choose 自由に作る (build anything) and build something you actually want

Stopping and resuming

  • Answering a question lets the build carry on
  • Do not do this at an approval stops the build there
  • Stopping MulmoTerminal in the middle of a step and starting it again retries that step and carries on
  • The instructions in the questions are enough to do what they ask without getting lost

Firebase (only if you know your way around it)

The Firebase base uses two Firebase projects, one for development and a separate one for production, and needs the pay-as-you-go (Blaze) plan. So far only publishing to the development project has been verified. Please do not approve publishing to production.

  • With the ミニ SNS (mini SNS) example, you can sign in with Google to the app published to development
  • With base Firebase and kind 社内向け業務アプリ (internal business app), the 稟議 (approval requests) example refuses an account outside the company domain, and the refusal screen is clear
  • When asked to do something in a console, the steps in the question are enough

When something goes wrong

What happened Where to look
Start is refused with Claude Code does not trust … yet Go through Trust a folder for the builds first again, and check the folder has not become a git repository
A step stopped What the check reported says why; Try again retries it
A change is refused with … run by the MulmoTerminal on port … Another MulmoTerminal on this machine is running. Use that one, or stop it
You want to clear a build’s record Delete that build’s folder under ~/.mulmoterminal/blueprints/runs/. The app’s own folder is left as it is

How to report

Comment on issue #2246 with what worked as well as what did not. It helps to include:

  • The MulmoTerminal version (npx mulmoterminal --version)
  • The base, the kind of system, and the example you used (or a summary of what you wrote yourself)
  • What you did, what happened, and what you expected
  • Screenshots, with the build’s URL (http://localhost:34567/blueprints/…)
  • For a stopped step, the text of What the check reported

Before posting, hide anything you would rather not share — email addresses, project ids, folder paths.

Known limitations

  • Publishing to Firebase production (protect onwards) has not been verified for real yet.
  • The console steps can drift out of date when the Firebase console changes. If one does not match, tell us which screen and what differed.
  • The check after publishing catches a blank page, but can miss an app stuck on its loading screen.
  • The Marketplace (installing packs from elsewhere) is a prototype; there is no official list yet.
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