JobyKit

An opinionated, agentic-first design-system kit for Phoenix + daisyUI apps.

JobyKit gives your AI coding agents a structured, machine-readable inventory of every UI component your app exposes — with prop signatures, daisyUI basis, rendered previews, and a stable contract — so design and prototype phases don't accumulate a hodgepodge of UI markup that's hard to reason about.

Why this exists

Most Phoenix apps end up with a sprawl of inline Tailwind classes, ad-hoc component shapes, and undocumented variants. AI coding agents working on those apps have to grep through HEEx to discover what's available and often just write new markup from scratch — making the sprawl worse.

JobyKit pushes the codebase in the opposite direction. Your app declares a manifest of its components, and JobyKit serves them at two surfaces:

Install

Generate a new app from scratch

Install the kit as a global Mix archive:

mix archive.install hex joby_kit

Then from anywhere:

mix joby_kit.new my_app   # wraps `mix phx.new` with the kit's HTML layer baked in
cd my_app
mix ecto.setup            # creates the dev DB and runs migrations
mix phx.server

Visit http://localhost:4000/. /design, /custom-designs, and /design.json are wired automatically.

Add to an existing Phoenix app

Add joby_kit to your deps:

def deps do
  [
    {:joby_kit, "~> 0.1"}
  ]
end

Then run one of:

# Adds the manifest, previews, design pages, and patches AGENTS.md +
# assets/css/app.css + your layout's nav. Idempotent.
mix joby_kit.install

# Same as install, plus replaces the default HomeLive at /, removes
# PageController/PageHTML. For a kit-flavored greenfield start.
mix joby_kit.bootstrap

JobyKit ships function components built on phoenix_live_view ~> 1.0 and assumes daisyUI is installed in your Tailwind config (the default for Phoenix 1.7+ apps generated with mix phx.new). Heroicons via the heroicons Tailwind plugin is also expected.

After running install or bootstrap, restart mix phx.server, visit /design and /custom-designs, and curl /design.json to see the manifest.

The rest of this README walks through the same steps manually for projects that prefer a hand-rolled wiring.

1. Declare your manifest

defmodule MyAppWeb.DesignManifest do
  use JobyKit.Manifest

  alias MyAppWeb.{CoreComponents, DesignPreviews}

  category :core,
    label: "Core wrappers",
    description: "One wrapper per daisyUI primitive."

  category :composite,
    label: "Composites",
    description: "Multi-primitive patterns reused across domains."

  category :domain,
    label: "Domain composites",
    description: "Composites tied to a product area."

  component CoreComponents, :button,
    category: :core,
    daisy_basis: "btn",
    summary: "Standard text button.",
    preview: &DesignPreviews.button_preview/1

  component CoreComponents, :card,
    category: :core,
    daisy_basis: "card",
    summary: "Padded content surface.",
    preview: &DesignPreviews.card_preview/1

  # ...one component/3 call per host wrapper

  @doc """
  Tells JobyKit which daisyUI primitives are wrapped, so the catalogue
  rendering flips them to :wrapped and links to the matching signature card.
  """
  def daisy_overrides do
    %{
      button: %{wrapper: "<.button>", anchor: "#jobykit-component-myappweb-corecomponents-button"},
      card: %{wrapper: "<.card>", anchor: "#jobykit-component-myappweb-corecomponents-card"}
    }
  end
end

2. Write preview functions

defmodule MyAppWeb.DesignPreviews do
  use Phoenix.Component
  # import your CoreComponents wrappers as needed

  def button_preview(assigns) do
    ~H"""
    <button class="btn btn-primary">Click me</button>
    """
  end

  # ...one *_preview/1 per registered component
end

3. Wire the routes

defmodule MyAppWeb.Router do
  use MyAppWeb, :router

  pipeline :authenticated_json do
    plug :accepts, ["json"]
    plug :fetch_session
    plug :put_secure_browser_headers
    # plug your auth pipeline; the controller does not enforce auth
  end

  scope "/", MyAppWeb do
    pipe_through [:browser, :require_authenticated_user]

    live "/design", DesignSystemLive, :index
    live "/custom-designs", CustomDesignsLive, :index
  end

  scope "/" do
    pipe_through :authenticated_json

    get "/design.json", JobyKit.ManifestController, :show,
      private: %{joby_kit_manifest: MyAppWeb.DesignManifest}
  end
end

4. Wrap the page components

defmodule MyAppWeb.DesignSystemLive do
  use MyAppWeb, :live_view

  def mount(_, _, socket), do: {:ok, assign(socket, page_title: "Design System")}
  def handle_event(_, _, socket), do: {:noreply, socket}

  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash}>
      <JobyKit.PageComponent.page_component
        manifest={MyAppWeb.DesignManifest}
        custom_path={~p"/custom-designs"}
      />
    </Layouts.app>
    """
  end
end

defmodule MyAppWeb.CustomDesignsLive do
  use MyAppWeb, :live_view

  def mount(_, _, socket), do: {:ok, assign(socket, page_title: "Custom Designs")}
  def handle_event(_, _, socket), do: {:noreply, socket}

  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash}>
      <JobyKit.PageComponent.custom_page_component
        manifest={MyAppWeb.DesignManifest}
        back_to={~p"/design"}
      />
    </Layouts.app>
    """
  end
end

That's it. Visit /design for the kit-curated catalogue; visit /custom-designs for your app's composites; curl /design.json to fetch the combined inventory for your AI agent.

The contract

JobyKit ships a five-step build order every consumer's /design page displays:

  1. Domain composite? Use it. Lives in a domain-scoped component module in this app. Surfaces on the custom-designs page.
  2. Generic composite? Use it. Multi-primitive pattern reused across domains in this app. Surfaces on the custom-designs page.
  3. Core wrapper? Use it. One wrapper per daisyUI primitive, defined in core_components. Surfaces on the kit page.
  4. daisyUI primitive? Wrap it as a core component first, then use the wrapper. The daisyUI catalogue at the bottom of /design lists every primitive.
  5. Build from tokens. Tailwind + theme tokens only. Expose the result as a core wrapper or composite and register it in the manifest.

And a five-rule wrapper contract every host component must satisfy:

  1. Declare every prop with attr.
  2. Carry data-component on the root element.
  3. Accept :rest, :global.
  4. Internals compose tokens + daisyUI primitives only.
  5. Register every component in the host manifest.

The agent surface (/design.json) is a single source of truth even when the two pages render different subsets — kit core, generic composites, and domain composites are all returned together with category labels.

What ships

License

MIT. See LICENSE.