Maple MCP

Speeds frontend reviews by placing comments directly on a deployed preview environment, which are then resolved by agents. A CI check holds the merge until all comments are resolved and maple's visual lint gates pass.

GitHub

Try this MCPSponsored

Documentation

maple-kit.org · Intro post · Pick a setup · Docs

A reviewer points at something on a preview deployment and says what is wrong. Maple captures where they pointed, what they were looking at and who they are, hands it to a coding agent in a form it can act on, and holds the merge until every comment is resolved.

Status: 0.x. All eight packages are published, with provenance, through a trusted publisher. 0.x makes no compatibility promise: a public interface is broken when breaking it is the right shape, and the changeset says what broke.

How it works

Four steps in a loop: mount Maple in a preview, a reviewer comments on the page, an agent fixes it over MCP, and a CI check holds the merge until every comment is resolved.

Mount: One route in your application, and one script in the preview build.
Comment: A reviewer points to an issue on the app. Maple records all the context needed for the agent to pick it up.
Fix: Your agent monitors new comments via the MCP, implements a fix and marks it as resolved.
Gate: A CI check holds the merge until all comments are resolved, and all visual gates pass.

Code got fast. Planning, definitions of done and edge cases did not, so they get skipped and surface in testing. Maple moves that review to the preview, where the comment can still be acted on.

What it does

An element, an area, or a passage. Pick a component, drag a box, or select the words that are wrong. The anchor finds it again after a redeploy.	Your agent picks it up over MCP. It waits for comments, reads each with its context, makes the change, and resolves it against the commit.
A merge gate. `maple/visual-review` fails while a comment is open and, if you want, until the reviewer approves.	The file and the line. A build-time tagger marks every JSX element with where it was written, so a comment arrives pointing at source.
Any state, on request. Type empty, failing or a thousand rows, and the page's API calls return it. A model picks the state; code writes every byte.	A score, if you want one. The comment is judged as it is typed, against five pillars, by a classifier you supply.

Each package's README shows the rest: the CLI, the design lint, flags and roles in a mock and the connectors.

Why another one

Pincushion, Vercel Toolbar, Chromatic, BugHerd and Marker.io each do some of this. None combines all four of:

Open source, Apache-2.0, with no hosted service required.
Deployed previews. Maple runs on the preview URL your CI already builds, so anyone with the link can comment — a designer, a product manager, a client. Tools like Agentation run against localhost, which means the only person who can leave a comment is the person running the build.
A merge gate — CI blocks while a visual comment is unresolved, and optionally until somebody says they looked. See docs/gate.md.
An agent loop — the agent reads comments, fixes, and resolves them.

Pick a setup

The SDK route has no default store: without one, its comment endpoints answer 404. Smallest setup first:

Try it locally No accounts and nothing wired in. Maple proxies your running app and keeps comments as files under `.maple/`. `maple review` _{review · CLI}	Review a preview alone Comments reach your machine through a loopback bridge. A guest cannot gate a merge. `maple solo <preview-url>` _solo
Review as a team Each reviewer signs in to GitHub through Device Flow, so every comment is written as its author. No secret sits in the preview. `maple setup app --owner=acme` _{GitHub auth · configuration · setup-maple-org}	Let an agent fix it The MCP server hands the agent each comment and resolves it against the commit. The Stop hook keeps the agent working while any are open. `/plugin install maple@maple-kit` _{agent loop · MCP · setup-maple-agent-loop}
Gate the merge `maple/visual-review` fails while a comment is open, and optionally until a reviewer approves. `maple setup ci --require-approval --write` _gate	Review edge-case states A reviewer names a state (empty, failing, a thousand rows), and the page's API calls return it. `import "@maple-kit/mock/install"` _{mock · package}
Bring your own backend A connector is plain Promise methods, and its capabilities are the methods it defines. `maple connectors` _{connectors · contribute-connector}	Host a shared store Not built yet. A file store in a preview pod loses its comments when the pod goes, so use GitHub or write a connector for now. _connectors

Add it to an app

The quickest wiring, for trying Maple on your own machine. Sharing a preview needs a store per reviewer: see Pick a setup.

npm install @maple-kit/core @maple-kit/ui @babel/core

@babel/core is an optional peer, and the tagger is what needs it: leave it out and tagger: true has nothing to transform with.

Mount the route and the tagger from the build, then render the overlay:

// vite.config.ts
import { createCommentStore } from "@maple-kit/core";
import { githubStore } from "@maple-kit/core/connectors";
import { maple } from "@maple-kit/core/vite";

const preview = process.env.MAPLE_PREVIEW === "1";

export default defineConfig({
  plugins: [
    react(),
    maple({
      tagger: preview,
      route: {
        // Local trial only: every comment is written as this one token.
        // The route has no default store; without one its comment endpoints 404.
        store: createCommentStore(
          githubStore({ owner: "acme", repo: "web", token: process.env.GITHUB_TOKEN! }),
        ),
      },
    }),
  ],
});

// main.tsx
import { Maple } from "@maple-kit/ui/maple";

createRoot(root).render(
  <>
    <App />
    <Maple branch={import.meta.env.VITE_MAPLE_BRANCH} />
  </>,
);

The shared GITHUB_TOKEN is for a local trial only. A preview other people review builds the store per request from each reviewer's own token, through the resolver in docs/github-auth.md, so a comment is authored by whoever wrote it and no GitHub secret sits in the preview.

Next.js uses withMaple from @maple-kit/core/next and a catch-all route at app/api/maple/[...maple]/route.ts; examples/next-app has both. The setup-maple-org skill walks through the GitHub App a reviewer signs in with.

Use with Claude Code

The Maple plugin bundles the skills that set Maple up and act on its comments, the MCP server that reads and resolves them, and the Stop hook that keeps an agent working while they are open:

/plugin marketplace add maple-kit/maple
/plugin install maple@maple-kit

The server and the hook read GITHUB_TOKEN, MAPLE_GITHUB_OWNER and MAPLE_GITHUB_REPO from the environment Claude Code starts in. In a project where the last two are unset, the hook lets every stop through.

To install only the skills, for Claude Code or any other agent the skills CLI supports, run npx skills add maple-kit/maple.

Vendor-agnostic by construction

Maple stores nothing itself. A connector is one file implementing plain Promise-returning methods:

import type { StoreConnector } from "@maple-kit/core/connectors";

export function myStore(options: MyOptions): StoreConnector {
  return {
    name: "my-store",
    async list(query) {
      /* … */
    },
    async append(comment) {
      /* … */
    },
  };
}

There are six kinds — store, media, observability, identity, gate and classifier — and a connector's capabilities are exactly the methods it defines. Run maple connectors to print the matrix from the code, or see docs/connectors.md.

Packages

Package	What it is
`@maple-kit/core`	Server SDK, overlay controller, connector contracts, build plugins.
`@maple-kit/ui`	The marks, the island and the composer: the overlay a reviewer uses.
`@maple-kit/react`	Hooks over the controller, for an overlay in your own design system.
`@maple-kit/mcp`	The MCP server an agent talks to, and a Stop hook.
`@maple-kit/cli`	The `maple` command.
`@maple-kit/mock`	Rewrites a page's API responses, flags and role into a named state.
`@maple-kit/classifier`	Scores a comment as it is written, and plans a mock from a sentence.
`@maple-kit/lint`	Design-system rules read off the page the browser laid out.

Documentation

Getting started

maple review: the overlay on a running app, nothing wired in
Configuration: every environment variable, and which are secrets
Examples: Vite and Next: real applications Maple mounts into
The CLI: review, solo, setup, connectors, mock plan

Reviewing

Solo mode: a guest's comments on their own machine
Drafts and publishing: why a comment is unsent until it is not
The JSX tagger: how a comment becomes file:line
Anchoring a region: how a dragged box finds its content again
Screenshots: the picture taken at pick time
Replies: decided, not built

Agent loop

The agent loop: the MCP tools and the Stop hook
@maple-kit/mcp: the server and the hook
setup-maple-agent-loop: connect and verify an agent
maple-review: turn a pull request's comments into a worklist

Merge gate

The merge gate: what blocks a merge, what approving does, which App to pin

States and scoring

Maple Mock: a model picks the state, code writes every byte
@maple-kit/mock: flags, roles and the runtime
The assist tier: what a score is, and what it is never allowed to be
@maple-kit/classifier: scoring and mock planning
Design lint: the rendered rules and the tiers around them
@maple-kit/lint: the rules as a package

Connectors and configuration

Connectors and the capability matrix
@maple-kit/core: server SDK, overlay controller, connector contracts
@maple-kit/ui: the overlay a reviewer uses
@maple-kit/react: hooks for an overlay in your own design system
Conventions in @maple-kit/ui
contribute-connector: scaffold a connector and run the contract suite

Security and organisations

Deploying Maple in an organisation: trust boundaries and a hardening checklist
GitHub authentication: Device Flow, the two Apps, the cookie, revocation
setup-maple-org: register and install the App
The overlay and CSP: what Maple asks of your policy
What a comment carries: the page text a comment stores
SECURITY.md: reporting a vulnerability

Contributing and internals

CONTRIBUTING.md and CODE_OF_CONDUCT.md
Releasing: changesets, trusted publishing, a new package name
The wordmark
Evals, with cases for assist, doc drift and mock plans
Demo recorder: how the clip above is made
Ported helpers, network mocks and the AI tier notes

Security

Report a vulnerability privately, as SECURITY.md describes. To run Maple in an organisation, read docs/security.md: who trusts what, which secrets exist where, and a checklist to work through before a preview is shared.

See it running

The project site is maple-kit.org. To run the Vite example yourself:

nvm use
pnpm install
pnpm --filter @maple-kit/example-vite dev   # http://localhost:5173

A real Vite application with three comments already on it: marks on the page, the island in the corner, and all three picks working against an SDK route the dev server mounts. examples/vite-app says what it does and does not prove.

Development

nvm use          # or fnm use, mise install — .nvmrc pins the version
pnpm install
pnpm hooks
pnpm lint && pnpm typecheck && pnpm test

Requires Node 24, the active LTS, and pnpm 10. Switch before the install: pnpm 10 and 11 load node:sqlite, which Node 23 does not have, so on the wrong version pnpm crashes rather than telling you the version is wrong. See CONTRIBUTING.md.

Licence

Apache-2.0. Contributions are accepted under the Developer Certificate of Origin — sign off with git commit -s. There is no CLA.