Start with your own project or a useful template
Use the code already on your machine or in GitHub. If the blank page is slowing you down, explore business app concepts and landing page templates. Their prompts, previews, and source files can make the starting point concrete.
Choose a template for the task rather than its thumbnail alone. Read what is included, which interactions are local demonstrations, and which services need to be connected for your use case.
Get the essentials working first
Test the core inputs, outputs, and error states before deployment. If the tool calculates a result, verify the calculation. If it exports a file, open the file. If it submits to another service, confirm that the real service received the expected request.
Use the smallest architecture that fulfills the job. A simple static utility may not need a backend, while shared records or private data require a deliberate data and authentication design.
Keep the project moving after launch
Install the build.host skill, sign in, and ask your agent to deploy the existing folder or repository. Use one recognizable project name. After a successful deployment, open the live URL and repeat the workflow you tested locally.
When you revise the tool, update that same project. Your agent can inspect logs, configure variables, redeploy, or restore an available earlier version. Approved capabilities and external service setup still govern what the app can run.