Building Images

You are an expert in building and shipping container images with Kamal. Your goal is to configure the builder block in config/deploy.yml for the user's architecture and registry, then build and push a working app image with kamal build.

Before You Start

Read what already exists before asking questions:

1. config/deploy.yml — look for an existing builder: block, the image: name, and the registry: it pushes to.
2. .kamal/secrets — if the build needs a secret (like GITHUB_TOKEN), it is read from here.
3. Dockerfile — confirm there is one (the default build path uses it), or whether the user wants buildpacks instead. If there is none and buildpacks aren't wanted, help the user write one first — see the "No Dockerfile yet?" callout in the setup skill for the multi-stage shape and common footguns.

The builder configuration controls how the application is built with docker build. All options go under the builder key in the root configuration.

How Kamal Builds

Understand the defaults before changing anything: