jay-contracts-and-plugins

name	jay-contracts-and-plugins
description	Read plugin.yaml files and materialized contracts from the agent-kit to understand available components, data shapes, and rendering phases. Use when you need to discover what plugins/contracts exist or understand a contract's tags before creating jay-html.

Contracts and Plugins Discovery

Setup

Run jay-stack agent-kit first to generate indexes and materialize dynamic contracts:

yarn jay-stack agent-kit

This writes to agent-kit/materialized-contracts/.

Reading the Plugins Index

File: agent-kit/materialized-contracts/plugins-index.yaml

materialized_at: '2026-02-09T...'
jay_stack_version: '1.0.0'
plugins:
  - name: wix-stores
    path: ./node_modules/@wix/stores
    contracts:
      - name: product-page
        type: static
        path: ./node_modules/@wix/stores/lib/contracts/product-page.jay-contract
      - name: product-search
        type: static
        path: ./node_modules/@wix/stores/lib/contracts/product-search.jay-contract

Fields:

• name — plugin name (use in plugin="..." attributes)
• path — path to plugin root (relative to project root)
• contracts[].name — contract name (use in contract="..." attributes)
• contracts[].type — static (defined in source) or dynamic (generated at runtime)
• contracts[].path — path to the .jay-contract file

Reading the Contracts Index

File: agent-kit/materialized-contracts/contracts-index.yaml

materialized_at: '2026-02-09T...'
jay_stack_version: '1.0.0'
contracts:
  - plugin: wix-stores
    name: product-page
    type: static
    path: ./node_modules/@wix/stores/lib/contracts/product-page.jay-contract
  - plugin: wix-stores
    name: product-search
    type: static
    path: ./node_modules/@wix/stores/lib/contracts/product-search.jay-contract

Use the path field to read the actual contract file.

Reading a Plugin's plugin.yaml

Located at the plugin's root (the path from plugins-index). Structure:

name: wix-stores
contracts:
  - name: product-page
    contract: product-page.jay-contract # path to contract file (relative to plugin)
    component: productPage # exported component name
    description: Complete headless product page
  - name: product-search
    contract: product-search.jay-contract
    component: productSearch
    description: Headless product search page
actions:
  - searchProducts
  - getProductBySlug
  - getCategories

Key fields:

• contracts[].name — contract name for contract="..." in jay-html
• contracts[].description — what the component does
• actions[] — action names for jay-stack action <plugin>/<action>

Reading a .jay-contract File

Contracts define the data shape (ViewState), interaction points (Refs), and rendering phases.

Tag Types

Type	Purpose	Jay-HTML Usage
data	Read-only data value	{tagName} binding
variant	Enum or boolean for conditions	if="tagName===value"
interactive	Element ref for user interaction	ref="tagName"
[data, interactive]	Both data and interactive	{tagName} + ref="tagName"
sub-contract	Nested object	{parent.child}
sub-contract + repeated: true	Array for loops	forEach="tagName" trackBy="..."

Phases

Phase	When	Example
slow	Build time (SSG)	Product name, description, static content
fast	Request time (SSR)	Live pricing, stock status
fast+interactive	Request + client updates	Price that updates on variant selection
(no phase)	All phases	Available everywhere

Props

Components that accept props declare them:

props:
  - name: productId
    type: string
    required: true
    description: The ID of the product to display

Use in jay-html: <jay:contract-name productId="value">.

Params

Page components with dynamic routes declare params:

params:
  slug: string

Params are always strings (URL params). Discover values with jay-stack params.

Contract Examples

Simple component with props:

name: ProductWidget
props:
  - name: productId
    type: string
    required: true
tags:
  - tag: name
    type: data
    dataType: string
    phase: slow
  - tag: price
    type: data
    dataType: number
    phase: slow
  - tag: inStock
    type: variant
    dataType: boolean
    phase: fast+interactive
  - tag: addToCart
    type: interactive
    elementType: HTMLButtonElement

Complex page with sub-contracts and loops:

name: product-page
tags:
  - tag: productName
    type: data
    dataType: string
  - tag: price
    type: data
    dataType: string
    phase: fast+interactive
  - tag: stockStatus
    type: variant
    dataType: 'enum (OUT_OF_STOCK | IN_STOCK)'
    phase: fast+interactive
  - tag: addToCartButton
    type: interactive
    elementType: HTMLButtonElement
  - tag: options
    type: sub-contract
    repeated: true
    trackBy: _id
    tags:
      - tag: _id
        type: data
        dataType: string
      - tag: name
        type: data
        dataType: string
      - tag: choices
        type: sub-contract
        repeated: true
        trackBy: choiceId
        tags:
          - tag: choiceId
            type: data
            dataType: string
          - tag: name
            type: data
            dataType: string
          - tag: isSelected
            type: variant
            dataType: boolean
            phase: fast+interactive
          - tag: choiceButton
            type: interactive
            elementType: HTMLButtonElement

Linked sub-contract (references another contract file):

- tag: mediaGallery
  type: sub-contract
  phase: fast+interactive
  link: ./media-gallery # refers to media-gallery.jay-contract in same dir

From Contract to Jay-HTML

Step-by-step

1. Read the contract — identify tags, their types, and phases
2. Map data tags → {tagName} bindings in HTML
3. Map variant tags → if="tagName===value" conditions
4. Map interactive tags → ref="tagName" on appropriate elements (HTMLButtonElement → <button>, HTMLInputElement → <input>, HTMLAnchorElement → <a>, HTMLSelectElement → <select>)
5. Map sub-contract with repeated: true → forEach="tagName" trackBy="..." loops
6. Map nested sub-contract → dotted paths ({parent.child}) or nested context inside forEach
7. Respect phases — don't bind fast-only data in slow-rendered static content

Quick mapping table

Contract Tag	Jay-HTML
{tag: title, type: data}	<h1>{title}</h1>
{tag: isActive, type: variant, dataType: boolean}	<span if="isActive">Active</span>
{tag: status, type: variant, dataType: "enum (A | B)"}	<div if="status===A">...</div>
{tag: btn, type: interactive, elementType: HTMLButtonElement}	<button ref="btn">Click</button>
{tag: link, type: interactive, elementType: HTMLAnchorElement}	<a ref="link">Go</a>
{tag: input, type: interactive, elementType: HTMLInputElement}	<input ref="input" value="{val}" />
{tag: items, type: sub-contract, repeated: true, trackBy: id}	<div forEach="items" trackBy="id">...</div>
{tag: detail, type: sub-contract}	{detail.field}