Installation

Seal has two halves, and a project adopts both: an seal command you install on your machine, and a Tilt extension your project’s Tiltfiles load straight from this repository. Only the first one is an install in the usual sense – Tilt fetches the second for you.

Prerequisites

Everything below is what Seal drives rather than what Seal is, so install them the way you normally would on your platform.

Tool	Why it’s needed
Docker	Builds every service’s image.
Tilt	What seal up/seal ci actually run.
kubectl	Talks to the cluster; reset scripts use it too.
uv	Installs and runs the seal CLI.
rsync	Copies test results out of the running containers. Present on most systems already.
Your store’s own CLI	Only if a service’s .env actually references a provider your project declares. Which CLI that is, and where to get it, are the cli and install_hint fields of your own seal-credentials-config.json – see Credentials.

You also need a local Kubernetes cluster, with kubectl’s current context pointed at it. Docker Desktop ships one – enable Kubernetes in its settings and the docker-desktop context appears; minikube, k3d, Rancher Desktop and kind all work the same way. Tilt refuses to deploy to a context it doesn’t recognise as local, so an accidental kubectl config use-context doesn’t put your work on a real cluster.

Check what you’re pointed at before the first run:

kubectl config current-context

Note

CI is where the cluster is throwaway rather than yours, so it creates one per run rather than reusing a developer’s: the reusable workflow uses ctlptl + kind. Nothing about a project depends on which of the two shapes it’s running against.

Installing the seal CLI

The repository is public, so uv can install the CLI straight from it. The package lives in the repository’s python/ subdirectory:

uv tool install "git+https://github.com/vdel/seal#subdirectory=python"

Check it worked:

seal

With no arguments seal prints its usage and exits non-zero, which is enough to tell you it’s installed.

Without installing

uvx runs the CLI from a temporary environment, which is worth reaching for in a one-off shell or a CI job that already has uv:

uvx --from "git+https://github.com/vdel/seal#subdirectory=python" seal up

From a checkout

If you’re working inside a clone of Seal itself – or developing against a fork – point uvx at the directory instead, so you always run the code as it is on disk:

uvx --from ../../python seal up      # from examples/angular-django/

Pinning a version works the way it does for any git dependency:

uv tool install "git+https://github.com/vdel/seal@v1.2.3#subdirectory=python"

Registering the Tilt extension

The Starlark half isn’t installed. Your project’s own root Tiltfile registers this repository as a Tilt extension repo once, near the top, and Tilt fetches it:

v1alpha1.extension_repo(name='seal', url='https://github.com/vdel/seal')
v1alpha1.extension(name='seal', repo_name='seal', repo_path='tilt/seal')

load('ext://seal', 'seal_service', 'select_k8s_overlay')

That is the whole registration. Anything else Seal needs – the official syncback extension, its own CI-cached build helper – it reaches for itself, under names of its own, so the name you pick here is free and nothing you register can collide with it.

Registration is session-wide: every Tiltfile your root one include()s afterwards, at any nesting depth, can load('ext://seal', ...) directly with no relative-path bookkeeping.

Developing the extension itself

Point url at a file:// path and Tilt picks up local, uncommitted edits:

v1alpha1.extension_repo(name='seal', url='file:///path/to/seal')

The worked example does exactly this, computed from config.main_dir rather than hardcoded, because it lives inside this repository. A project that forked Seal into its own repository uses its fork’s URL instead.

Installing the agent skills

Optional, and it installs into your repository rather than onto a machine: a repository built on Seal can carry the instructions a coding agent reads to use it – what replaces tilt up, what an outcome test is, what never to edit.

git clone --depth 1 https://github.com/vdel/seal /tmp/seal
/tmp/seal/bin/install-seal-skills --target .

Commit what that writes and every teammate, and every agent session, gets them. See Coding agents.

Next

Quickstart runs the worked example end to end.