marklayer-mcp

MCP (Model Context Protocol) server that bridges MarkLayer annotations to AI coding agents.

When users annotate any webpage with MarkLayer, your agent receives the comments as a structured work queue: it can acknowledge, resolve, dismiss, and reply to each one — and the human sees the status updates live. It also works the other way: point an agent at a room and ask it to review the page, and it can leave its own comments and copy-edit suggestions for the human to triage.

Install

You may not need to. Every MarkLayer share link is already a remote MCP server at the same address plus /mcp, so a client that supports remote (Streamable HTTP) servers connects with nothing installed:

claude mcp add --transport http marklayer https://marklayer.app/s/abc123/mcp

Append ?agent=cursor, or any name, so the people in the room see who is working; it defaults to agent. That endpoint is bound to its room, so it has every tool below except marklayer_connect_room.

This package is the stdio version of the same tools, with no Claude-specific wiring. Use it when a client cannot reach remote servers, or when you want one install that covers every room (Claude Code, Cursor, Windsurf, VS Code, Codex CLI, etc.):

# Claude Code:
claude mcp add marklayer -- npx -y marklayer-mcp

# Or pre-connect to a specific room:
claude mcp add marklayer -- npx -y marklayer-mcp --room https://marklayer.app/s/abc123

For any other MCP client, add a stdio server entry pointing at the same command (adjust the config file/key to your client — Cursor's ~/.cursor/mcp.json, Windsurf's mcp_config.json, VS Code's .vscode/mcp.json, etc.):

{
  "mcpServers": {
    "marklayer": {
      "command": "npx",
      "args": ["-y", "marklayer-mcp"],
      "env": { "MARKLAYER_AGENT": "cursor" }
    }
  }
}

Set MARKLAYER_AGENT (or --agent) to identify which agent this is — it's what humans see as the comment author and the "assigned to" badge, so a non-Claude client should not leave it at the default.

Usage

In your agent prompt:

Watch my MarkLayer annotations. For each one, acknowledge it, make the fix, then resolve it with a summary.

The agent will call marklayer_watch_annotations in a loop and process incoming feedback as it arrives.

Tools

Tool	Description
marklayer_connect_room	Connect to a room by share URL or bare id.
marklayer_room_info	Page URL, viewport width, timestamps.
marklayer_read_page	The page's headings, text, links and controls, with selectors. Lets the agent review a page nobody has annotated yet.
marklayer_list_annotations	List annotations, optionally filtered by status.
marklayer_get_annotation	Full detail + reply thread for one annotation.
marklayer_watch_annotations	Block until new annotations arrive, return a batch.
marklayer_acknowledge	Mark in-progress and tag with this agent.
marklayer_resolve	Mark resolved, optionally posting a reply with the summary.
marklayer_dismiss	Mark dismissed with a reason the human will see.
marklayer_reply	Post a reply without changing status (e.g. clarifying questions).
marklayer_create_annotation	Leave a new comment yourself — proactive feedback rather than a response.
marklayer_suggest_edit	Propose an exact copy/grammar fix for a piece of text, as a diff the human can accept.

Options

--room <url-or-id>   Connect at startup; otherwise call marklayer_connect_room.
--api-base <url>     Override worker URL (default https://marklayer.app).
--agent <name>       Identifier shown to humans (default "claude-code").

Equivalent env vars: MARKLAYER_ROOM, MARKLAYER_API_BASE, MARKLAYER_AGENT.

Troubleshooting

"Connection closed" on first start. npx -y downloads the package on the first run, and a cold download can outlast the MCP client's startup timeout. Prime the cache once (npx -y marklayer-mcp --help) and reconnect, or install it up front with npm i -g marklayer-mcp and point the client at the binary.

Tools return "room is not connected". The WebSocket dropped — rooms are held open by a Durable Object and a long-idle agent can be disconnected. Call marklayer_connect_room with the same URL to reattach.

Creating rooms programmatically

This server consumes an existing share link. To mint one (or many) from code — e.g. seed a room per page in a batch of URLs before pointing the agent at it — POST directly to the public HTTP API:

curl -X POST https://marklayer.app/api/$ID \
  -H 'Content-Type: application/json' \
  -d '{"ops":[],"url":"https://example.com/page-1","width":1440,"expires_in":2592000}'
# Share link: https://marklayer.app/s/$ID

$ID is caller-supplied (use nanoid / crypto.randomUUID() — it's the access token). No auth, no SDK. Full details: https://marklayer.app/llms-full.txt