foldkit-plus

foldkit-plus

Packages that extend a Foldkit application outward — to agents, servers, other devices, the URL, and design systems — without giving it a second place to keep state.

A Foldkit application is one state machine: a Schema-typed Model, a Message union naming everything that can happen, and one pure update function that turns a Message into the next Model and some Commands. That shape is easy to reason about, test, and replay. It gets lost the moment an app grows a cache in a hook, a store in the URL, a tool handler that re-implements a transition, or a sync layer with its own reducer.

Everything in this repository keeps the one state machine. An agent can only send Messages update already handles. Server data lives in the Model and is reconciled by update. Replicas replay the same Messages through the same update. The URL and local storage mirror a slice of the Model; they never own one. Views are styled from outside without forking. Each package answers one question, and they compose because they meet at explicit application boundaries.

The website: foldkit-plus.pages.dev has each package's guides and API reference, and the demos, each an example from this repository built as static files. Those with a server run it in your browser, shared by every tab, so nothing you do leaves it:

• A blog studio and its site (examples/cms): Drafts beside the row, revisions, scheduled publishing and a page builder, with the public site rendered at build time.
• Two devices, one registry (examples/registry): Two devices edit 10,000 products in a data grid, offline and in conflict, and agree once both are back.
• Pages two tabs edit at once (examples/pages): Rich text two people edit at the same time, online or not, converging through one journal.
• A todo list an agent can use (examples/todo-app): One application definition drives the view, the tools an agent calls, the document replicas share, and the policy the server enforces.
• A data grid over 100,000 rows (examples/data-grid): A grid that owns focus, selection, columns and the open editor, while the application owns every row.
• Eight widgets from shared primitives (examples/widgets): Once the capabilities exist, a family of widgets gets cheap: each one is a Bundle placement plus Behaviors on a shared Collection description, with no bespoke state machine.

Choose who owns the state

What you are adding	Authoritative owner	Extension
Local UI state or a reusable widget	Parent Model and its update/child update	Bundle, Primitives
Facts loaded from a server	Server; the client cache is disposable	Remote
Offline edits that must converge	Client-authored operations in an authoritative journal order	Sync + Durable
Offline edits to rows a server owns	The journal; the table is its read model	Sync (/entity, /journal) + Remote
An interactive grid over the application's rows	The grid's Bundle for focus, selection and columns; the rows stay the application's	Data grid
A URL or remembered preference	Local Model; the external value is a representation	Mirror
Agent access or a customizable view	Existing state and transitions	Agent, Surface, Mixins

A Surface can observe several owners. Observing a field does not grant a second package permission to change it outside its owning transition.

intent → Message → update → Model → Projection / Surface → consumer
                      |
                      └→ Command → result Message → update

Sixty seconds of code

Start with one mechanism: an inspectable boundary around an existing Model.

The fastest way to see how the packages compose is to watch several of them reuse one application declaration. Assume Model, Message, initial, and update are an ordinary Foldkit todo app you already wrote. Everything around them derives from the same state machine; none of it introduces a second reducer.

import { Schema } from 'effect'
import { Agent } from 'foldkit-agent'
import { Mirror } from 'foldkit-mirror'
import { Capability, Slot, Slots, Style } from 'foldkit-mixins'
import { SurfaceView } from 'foldkit-mixins-surface'
import { MessageSet, Module, Projection, Surface } from 'foldkit-surface'
import { DocumentId, Sync } from 'foldkit-sync'

type Principal = { readonly role: 'owner' | 'guest' }
const isOwner = (principal: Principal) => principal.role === 'owner'

// 1. This is still the application: one Model, one Message union, one update.
// Surface adds typed references and inspection metadata; it does not add runtime state.
const App = Surface.application({ Model, Message, initial, update })

// 2. A Surface is a public boundary for a feature: what it may observe and cause.
// A renderer bound to Board can only construct these two Messages.
const Board = App.surface('Board', {
  model: ({ model }) => ({ todos: model.todos, filter: model.filter }),
  messages: [Message.ToggledTodo, Message.DeletedTodo],
})

// A read-only Surface can be reused by something that only needs context.
const Overview = App.surface('Overview', {
  model: ({ model }) => ({ todos: model.todos, filter: model.filter }),
})

// 3. Mixins separate "where customization is allowed" from "what gets attached there."
//
// BoardSlots is the view's public customization contract. It renders nothing by
// itself. It only names the places the view agrees other code may extend later:
// `root` will be the outer <section>; `list` will be the <ul>.
// Capabilities describe what kind of element lives at each point so incompatible
// Styles or Behaviors can be rejected instead of silently doing the wrong thing.
const BoardSlots = Slots.define({
  root: Slot.make({ capability: Capability.Container }),
  list: Slot.make({ capability: Capability.Collection }),
})

// Style is data written against that slot contract. Nothing is applied yet, and
// BoardStyle cannot read or change application state. Because it is created with
// `forSlots(BoardSlots)`, misspelling a slot or styling one Board never published
// is a type error rather than a convention.
const BoardStyle = Style.forSlots(BoardSlots)({
  root: Style.class('todo-board'), // contribute a class to the `root` slot
  list: Style.inline({ margin: '0', padding: '0', listStyle: 'none' }), // style `list`
})

// SurfaceView.define ties three boundaries together:
//   Board      -> the projected Model this view receives and the Messages it may emit
//   BoardSlots -> the places outside customization may attach
//   render fn  -> the actual markup
//
// So `model` is not the whole application Model; it is Board's { todos, filter }.
// And `h` is typed to the Messages Board declared above.
export const BoardView = SurfaceView.define(Board, BoardSlots, (model, slots, h) =>
  h.section(
    // `.attrs()` is the handoff point between markup and Mixins. It resolves the
    // view's own attributes plus every Style/Behavior attached to `root` into
    // ordinary Foldkit attributes for this <section>.
    slots.root.attrs(),
    [
      h.ul(
        // Same idea here: this exact DOM position is the published `list` slot.
        slots.list.attrs(),
        model.todos.map(todo => h.li([], [todo.title])),
      ),
    ],
  ),
).pipe(
  // Attach appearance from the outside. BoardView never imports CSS decisions into
  // its markup, so styles can be swapped/composed without copying the component or
  // adding a growing collection of styling props.
  Style.attach(BoardStyle),
)

// Behavior can attach element-level interaction through those same slots. It may
// contribute attributes, event handlers, or a Mount, but it still owns no Model;
// application state and transitions remain Model / Message / update.

// 4. Sync declares ownership of one writable slice and the facts that change it.
// Projection.pick is writable because checkpoints must install back into Model;
// replay still runs these Messages through the application's own update.
const TodoSync = Sync.forApplication(App)
  .withPrincipal<Principal>()
  .make({
    documentId: DocumentId.make('todos'),
    shared: Projection.pick(App.model.todos),
    durable: MessageSet.make(App, [
      Message.SubmittedTodo,
      Message.ToggledTodo,
      Message.DeletedTodo,
    ]),
    authorize: {
      // Policy lives on the contract and is enforced by the server journal.
      DeletedTodo: ({ principal }) => isOwner(principal),
    },
  })

// The server gets codecs, empty snapshot, replay, and authorization from Sync.
// There is no second server-side reducer to keep in agreement.
TodoSync.journalContract()

// 5. First specialize the Agent API to this application and Principal type.
// `forApplication(...).withPrincipal(...)` does NOT create an agent; it creates
// a typed builder whose helpers know App's Model, Message union, and Principal.
const AgentBuilder = Agent.forApplication(App).withPrincipal<Principal>()

// `make` creates the concrete agent contract that MCP/WebMCP/A2A/etc. can serve:
// what this agent sees, which existing Messages it may cause, and their policy.
const AssistantAgent = AgentBuilder.make({
  context: Overview,
  messages: AgentBuilder.expose(Message, {
    RequestedTodo: Agent.variant({
      name: 'add_todo',
      description: 'Add a todo with the given title',

      // The protocol input can be smaller than the internal Message. The call's
      // invocation id rides on the intent, and the Command copies it onto the fact.
      input: Schema.Struct({ title: Schema.String }),
      toMessage: ({ title }, { invocation }) => ({ title, requestId: invocation.id }),

      // RequestedTodo is an intent. The tool call completes when update later
      // applies the durable fact that carries this call's id: two calls adding
      // "Milk" each finish on their own todo, which a title could not tell apart.
      completion: {
        success: Message.SubmittedTodo,
        correlate: (_, result, { invocation }) => result.requestId === invocation.id,
      },
    }),
    ToggledTodo: { name: 'toggle_todo', description: 'Toggle a todo' },
    DeletedTodo: {
      name: 'delete_todo',
      description: 'Delete a todo (owner only)',
      // Same rule, checked early at the agent boundary; the journal still owns trust.
      authorize: ({ principal }) => isOwner(principal),
    },
  }),
})

// 6. Mirrors do not own state. They are secondary representations of Model fields.
const Filters = Mirror.url(App, {
  name: 'filters',
  fields: [App.model.filter], // linkable: ?filter=active
})
const Prefs = Mirror.kv(App, {
  key: 'todo/prefs',
  fields: [App.model.draft], // remembered on this device
})

// 7. The architecture itself is data. Validate ownership/capability relationships,
// or turn the same declarations into documentation and tooling input.
const Project = Module.make(App, [
  Board,
  Overview,
  TodoSync,
  AssistantAgent,
  Filters.contract,
  Prefs.contract,
])

Module.validate(Project) // []
Module.toMermaid(Project) // architecture generated from the declarations above

The code is large because the point is composition, not because any one package requires all of it.

1. The application stays the center. Model, Message, update, Commands, Submodels, and Mounts still mean what they mean in Foldkit.
2. Surface makes boundaries explicit. A Projection says what a consumer may observe; a Message subset says what it may cause. Those declarations are data, so other packages can reuse and inspect them.
3. Extensions reuse application semantics instead of copying them. Agents expose existing Messages, Sync replays them, Mirror represents Model fields elsewhere, and Mixins extends views without owning state.
4. Ownership stays singular. A URL mirror does not become a URL store; a replica does not grow a second reducer; a Style does not become view state.
5. The architecture itself becomes inspectable. Module.validate catches conflicting ownership, and Module.toMermaid turns the declarations into documentation or tooling input.

State changes take exactly two paths, and they are not equal. Ordinary application transitions travel Message → update. Everything else, such as a Sync checkpoint, a Mirror restoration or a Remote cache write, installs an already-derived value through a structural seam (ModelRef.set/modify, WritableProjection.set). A setter is infrastructure, not a second update; see Who changes application state, and how.

The important part is what is missing: no agent reducer, sync reducer, URL store, persistence state machine, server copy of the shared schema, or forked component just to restyle it.

foldkit-remote is deliberately not in this block. Remote is easiest to understand with an actual server-owned entity and query; see the Remote example or the kitchen-sink for that path. For the running version of this app, follow the todo app.

The sample above is typechecked in examples/todo-app/test/readme.test-d.ts, so the front page cannot quietly drift from the API.

Which package do I need?

If a term below is new, the glossary defines each one in a line.

You want to…	Reach for	Read
Let an LLM or another agent use the app, safely, over MCP, WebMCP, A2A, or Agent Native	foldkit-agent + one adapter	Agents
Cache server entities once, know what is missing, mutate optimistically, get live updates	foldkit-remote (+ -server, -drizzle on the server)	Server-derived state
Work offline, on several devices, or with other people, and converge	foldkit-sync on the client, foldkit-durable on the server	Replicated state
Edit rows a server owns offline, with the table kept as the journal's read model	foldkit-sync/entity and foldkit-sync/journal, over foldkit-remote	Editing server data
Keep the filter and page in the URL, remember a draft or a preference	foldkit-mirror	Mirrored state
Declare where the application is: route nodes, typed targets, titles, history intent	foldkit-site (experimental, 0.1.0)	package README
Package a Submodel once and place it several times, or once per key, with every part wired	foldkit-bundle (+ -surface for Module ownership)	package README
Reach for everyday browser primitives instead of hand-wiring them: media queries, timers, sockets, device state, observers, clipboard, one in-browser server for every tab	foldkit-primitives	package README
Restyle or add behaviour to views, including @foldkit/ui, without copying markup	foldkit-mixins (+ -surface, -ui)	View composition
Use a React component in a Foldkit view, or embed a Foldkit program in a React app	foldkit-react	package README
Compile Foldkit views to React TSX source	foldkit-react-codegen	package README
Say what a feature observes and may cause, and check that nothing owns a field twice	foldkit-surface	package README
Declare a domain once (fields, relations, selections) for the client cache, the database binding, and forms to share	foldkit-entity	One domain declaration
Say once who may read and write what, and have every read, write, Sync edit and agent capability enforce it	foldkit-guard	package README
Build a form from the input an operation accepts, with validation and a decoded value handed to the parent	foldkit-form (+ foldkit-mixins-form to draw it)	package README
Join a form, a Remote mutation or query, and their Entity into an edit screen or a list	foldkit-crud (+ foldkit-mixins-crud to draw lists and details)	package README
Edit an interactive grid over rows the application owns: keyboard focus, ranges, typed editors, copy and paste, fill, 100,000 rows virtualized	foldkit-data-grid (+ foldkit-mixins-data-grid to draw it; experimental, 0.1.0)	package README
Render on the server and hand the Model over, rather than rerunning init: resumable pages, forms without scripts	foldkit-ssr	package README
Give content drafts, revisions, a schedule, and a published/unpublished boundary, without a status column	foldkit-cms + foldkit-cms-drizzle (the editor's state and the server)	package README
Edit rich text: a semantic document in the Model, an editor on the page, Markdown in and out	foldkit-richtext + foldkit-richtext-dom (+ -markdown, -code or -code-shiki for highlighted code, and foldkit-mixins-richtext to draw the chrome)	package README
Store a page as Blocks in Regions, checked against a Catalog of what may exist	foldkit-composition (experimental, 0.1.0)	package README
Edit such a page with a selection and undo, as one key of a form	foldkit-builder (+ foldkit-mixins-builder to draw it; experimental, 0.1.0)	package README

foldkit-surface is the shared semantic seam for Agent, Remote, Sync, Mirror, and the Surface/Mixins bridge. It is not a mandatory base class for the whole repository: foldkit-durable, core foldkit-mixins, and the protocol/UI adapters can stand on their own and meet Surface-backed packages at explicit boundaries.

How they fit together

flowchart TB
  app["Foldkit application<br/>Model · Message · update · Commands"]
  surface["foldkit-surface<br/>Projection · field refs · Message subsets · Module"]
  agent["foldkit-agent"]
  agentAdapters["foldkit-agent-webmcp · foldkit-agent-mcp<br/>foldkit-agent-a2a · foldkit-agent-native"]
  remote["foldkit-remote<br/>normalized server cache"]
  server["foldkit-remote-server"]
  drizzle["foldkit-remote-drizzle"]
  sync["foldkit-sync<br/>local replica"]
  durable["foldkit-durable<br/>ordered server log"]
  mirror["foldkit-mirror<br/>URL · KeyValueStore"]
  bundle["foldkit-bundle<br/>Submodel placements"]
  bundleSurface["foldkit-bundle-surface"]
  primitives["foldkit-primitives<br/>ready-made bundles · entries · Mounts"]
  mixins["foldkit-mixins<br/>typed view extension points"]
  mixinsSurface["foldkit-mixins-surface"]
  mixinsUi["foldkit-mixins-ui"]
  entity["foldkit-entity<br/>the domain, declared once"]
  guard["foldkit-guard<br/>who may do what · enforced on every seam"]
  form["foldkit-form<br/>headless form from an operation's input"]
  mixinsForm["foldkit-mixins-form"]
  mixinsCrud["foldkit-mixins-crud"]
  cms["foldkit-cms<br/>drafts beside the row · derived state"]
  cmsDrizzle["foldkit-cms-drizzle<br/>audience boundary · drafts · publish"]
  crud["foldkit-crud<br/>editor · list · detail · remover"]
  metadata["foldkit-metadata<br/>opaque typed metadata"]
  ssr["foldkit-ssr<br/>server render · Model handover · resume"]
  richtext["foldkit-richtext<br/>semantic documents · transactions"]
  richtextDom["foldkit-richtext-dom<br/>contenteditable adapter · editor Bundle"]
  mixinsRichtext["foldkit-mixins-richtext<br/>toolbars · menus · handle · source mode"]
  richtextMarkdown["foldkit-richtext-markdown<br/>Markdown in and out · source sessions"]
  richtextCode["foldkit-richtext-code · -code-shiki<br/>code tokenizers · syntax decorations"]
  react["foldkit-react<br/>React islands · Foldkit in React"]
  reactCodegen["foldkit-react-codegen<br/>views compiled to React TSX"]
  composition["foldkit-composition<br/>a page as Blocks in Regions · experimental"]
  builder["foldkit-builder<br/>the page editor, as a form key · experimental"]
  mixinsBuilder["foldkit-mixins-builder<br/>the page editor, drawn · experimental"]
  dataGrid["foldkit-data-grid<br/>grid geometry · experimental"]
  mixinsDataGrid["foldkit-mixins-data-grid<br/>the grid, drawn · experimental"]

  app -- "describe observation / capability" --> surface
  app --> mixins
  app --> bundle --> bundleSurface
  app --> primitives
  app --> dataGrid
  bundle --> dataGrid
  dataGrid --> mixinsDataGrid
  crud -- "rows from a list" --> dataGrid
  sync -- "edits to server rows" --> remote
  mixins --> mixinsDataGrid
  bundle --> primitives
  surface --> bundleSurface
  surface --> agent --> agentAdapters
  surface --> remote --> server
  drizzle --> server
  surface --> sync --> durable
  surface --> mirror
  surface --> mixinsSurface
  mixins --> mixinsSurface
  mixins --> mixinsUi
  entity -- "read by" --> remote
  entity -- "bound to tables" --> drizzle
  entity --> form
  entity --> guard
  guard --> cmsDrizzle
  bundle --> form
  form --> mixinsForm
  mixins --> mixinsForm
  form --> crud
  crud --> mixinsCrud
  entity --> cms
  form --> cms
  crud --> cms
  cms --> cmsDrizzle
  drizzle --> cmsDrizzle
  mixins --> mixinsCrud
  remote --> crud
  metadata --> surface
  metadata --> entity
  metadata --> composition
  composition --> builder
  bundle --> builder
  form --> builder
  primitives --> builder
  builder --> mixinsBuilder
  mixins --> mixinsBuilder
  surface --> ssr
  remote -- "resume part" --> ssr
  app --> richtext --> richtextDom
  richtext --> richtextMarkdown
  richtext --> richtextCode
  richtextMarkdown --> mixinsRichtext
  bundle --> richtextDom
  richtextDom --> mixinsRichtext
  mixins --> mixinsRichtext
  app --> react
  app -- "views read as source" --> reactCodegen

The arrows are integration boundaries, not new application state machines. Agent projects application capabilities. Remote reconciles server facts into the Model. Sync replays application Messages against an authoritative server order. Mirror keeps a secondary representation of Model fields. Mixins extends view structure without touching Model state. Primitives packages reusable browser and clock behaviour without hiding state. Entity declares a domain once as plain values; Remote, the Drizzle binding, and Form read it, and Crud joins a form to a Remote operation. Form and Crud own their submodel transitions inside the parent Model; Entity describes structure without holding runtime state. Durable can also be used independently as an ordered server journal.

The rule that makes the whole graph composable is one owner per datum:

State	Owner	Package
The route, the selection, a transient error	the local Model, plain update	—
A reusable child machine's slice, placed once or per key	the parent Model	foldkit-bundle places
A media query, timer reading, socket state, device list, or clipboard result	the parent Model	foldkit-primitives places
A filter the URL shows, a draft a device remembers	the local Model	foldkit-mirror observes
Facts owned by another system	the server	foldkit-remote caches
Client-authored state that must survive offline and converge	the durable log	foldkit-sync + foldkit-durable
An edit to a row the server owns, until the table has it	the journal; the table is its read model	foldkit-sync/entity lays it over Remote's row
Which cell has focus, what is selected, how the columns stand	the grid's Bundle in the parent Model	foldkit-data-grid places
What an agent may see and do	the application	foldkit-agent observes and exposes

That ownership rule is more important than the package boundaries. A single Surface may read across local state, Remote state, and Submodels because a Surface is an observation/capability boundary, not a second owner.

Try it

Start with examples/todo-app. It is the browser version of the architecture above: local-first state, owner-only rules, WebMCP tools, a linkable filter, and view composition around one Foldkit application.

For the broadest integration trace, use examples/kitchen-sink. For one concept at a time:

Example	Shows
examples/todo	Agent contracts and WebMCP
examples/sync	durable Messages, replicas, and server ordering
examples/remote	normalized server-owned state end to end
examples/mixins	typed view extension points end to end
examples/cloudflare	Remote over D1, Sync through a Durable Object, live by re-reading D1, and a Pages list of Entity, Form, and Crud

The application examples print transcripts with important lines pinned by tests. pnpm demo runs the root integration sequence; run the CMS demo separately. The examples index gives the recommended reading order.

Install

Tell your coding agent to run:

npx foldkit-plus setup

It reads your project and prints what to install with your package manager, the effect or foldkit version that needs changing, the agent skill, and which package does which job. By hand, foldkit-plus brings every package at once, each under a subpath named for it (foldkit-plus/remote-server):

pnpm add effect@4.0.0 foldkit@0.168.0 @effect/platform-browser@4.0.0 foldkit-plus

Or install the pieces for the boundary you are adding; the packages are designed to be adopted independently.

# typed application boundaries
pnpm add foldkit-surface

# agent capabilities + one protocol adapter
pnpm add foldkit-agent foldkit-agent-webmcp

# normalized server-owned state
pnpm add foldkit-surface foldkit-remote
pnpm add foldkit-remote-server foldkit-remote-drizzle drizzle-orm # optional server compilation

# local-first replicated state
pnpm add foldkit-surface foldkit-sync foldkit-durable

# URL / local key-value representations
pnpm add foldkit-mirror

# reusable Submodels placed with every part wired
pnpm add foldkit-bundle foldkit-bundle-surface foldkit-surface

# a domain declared once, forms from an operation's input, and edit screens
pnpm add foldkit-entity foldkit-form foldkit-mixins-form
pnpm add foldkit-guard # who may do what, declared on the domain and enforced on the server
pnpm add foldkit-crud foldkit-remote # an editor, list, detail, and remover over Remote
pnpm add foldkit-mixins-crud # draws a list as a table and a detail as a description list
pnpm add foldkit-cms # content types, drafts beside the row, and a derived lifecycle
pnpm add foldkit-cms-drizzle drizzle-orm # its server: the audience boundary, drafts, and a publish that is whole

# an interactive data grid, and the accessible view that draws it
pnpm add foldkit-data-grid foldkit-mixins-data-grid

# rich text: the document, the editor on the page, Markdown and code
pnpm add foldkit-richtext foldkit-richtext-dom foldkit-mixins-richtext
pnpm add foldkit-richtext-markdown foldkit-richtext-code

# server rendering that hands the Model over
pnpm add foldkit-ssr

# ready-made primitives: media, timers, sockets, observers, clipboard
pnpm add foldkit-primitives

# view extension points
pnpm add foldkit-mixins foldkit-mixins-surface

# React interop in either direction
pnpm add foldkit-react react react-dom
pnpm add -D foldkit-react-codegen # views to TSX source

Other agent adapters are foldkit-agent-mcp, foldkit-agent-a2a, and foldkit-agent-native; foldkit-mixins-ui adapts compatible @foldkit/ui components.

foldkit and effect are peer dependencies. These packages ask for effect@^4.0.0 and are tested on 4.0.4; Foldkit 0.168.0 itself asks for exactly effect@4.0.0 and @effect/platform-browser@4.0.0, so an application on it installs those. foldkit-durable's Node entry requires Node 22 for node:sqlite; foldkit-durable/core runs on any SQLite client, a browser's included. drizzle-orm is a peer of the Drizzle packages, so the application's copy is the one they use. The release matrix lists every package's current version.

Agent skill

skills/foldkit-plus is an Agent Skill that teaches a coding agent what each package owns, when to reach for it, and a basic example of each. Install it into Claude Code, Cursor, OpenCode, and other agents with skills.sh:

npx skills add doeixd/foldkit-plus --skill foldkit-plus

Go deeper

The root README is the map. The guides teach the architecture and each package README documents its API.

Topic	Guide
Agent contracts and adapters	Agents
Server-owned normalized state	Server-derived state
One domain for the cache, the database, forms, and edit screens	One domain declaration
Local-first replication and the durable server log	Replicated state
URL and key-value mirrors	Mirrored state
Inside-out view composition	View composition
Running a Foldkit app over a replica	Runtime binding
Design lineage and prior art	Prior art and design lineage

The 0.7 release post introduces Entity, Form, and Crud. The documentation map gives the full reading order, package references, design notes, and historical material. The release matrix tracks published versions; the revision plan records ongoing design work.

Status

Foldkit Plus is 0.x, built against a 0.x Foldkit and Effect 4. APIs are still settling and minor releases may break. The CHANGELOG records what changed and why.

The repository is exercised as a system: package tests run in CI, README-facing examples are type-checked or pinned as deterministic transcripts, and pnpm demo runs the worked examples together.

Contributing and releasing

pnpm install
pnpm format:check
pnpm typecheck
pnpm test
pnpm demo

See CONTRIBUTING.md for the full development workflow and AGENTS.md for repository working agreements and documentation standards. Release mechanics and the package/version matrix live in docs/releases.md.

License

MIT. These are community packages, published unscoped as Foldkit itself is. They are not affiliated with or endorsed by the Foldkit maintainers, and the names are theirs for the asking.

References

• Foldkit — https://foldkit.dev/ · https://github.com/foldkit/foldkit
• WebMCP — https://github.com/webmachinelearning/webmcp
• Agent Native — https://github.com/BuilderIO/agent-native