Cnvs.app

What cnvs.app MCP server does

The cnvs.app MCP server gives an AI agent access to a shared canvas at https://cnvs.app/mcp. Agents can create and inspect boards, retrieve visual previews, and modify text, links, images, strokes, and other canvas content. The available tool set also covers movement and deletion, live-update waits, and kanban operations involving columns, lanes, tasks, queries, and exports.

The board is shared with human collaborators in real time. A board ID or board URL identifies the workspace; there is no account creation or OAuth flow. The repository also includes Agent Skills that describe workflows for reading state, previewing drawings, editing boards, and responding to human changes.

How it works

The cnvs.app MCP server uses Streamable HTTP at https://cnvs.app/mcp and declares protocol version 2025-06-18. It exposes three subscribable resources:

• cnvs://board/{id}/state.json for the complete board snapshot
• cnvs://board/{id}/preview.svg for a rendered visual view
• cnvs://board/{id}/tasks.json for kanban state

Clients can subscribe with resources/subscribe. After activity settles, the service sends resource update notifications over SSE, typically with about a three-second debounce. For clients or runtimes without MCP support, state-changing REST equivalents are available below https://cnvs.app/api/boards/<id>/, and a long-poll endpoint can wait for changes.

Setup and configuration

No local process or secret is required. Add the hosted endpoint as an HTTP MCP server in a compatible client's mcpServers configuration:

{
  "mcpServers": {
    "cnvs": {
      "type": "http",
      "url": "https://cnvs.app/mcp"
    }
  }
}

Claude Code can add the same connection with claude mcp add --transport http cnvs https://cnvs.app/mcp. The repository also contains marketplace package metadata for Codex/ChatGPT and Cursor.

The cnvs.app MCP server does not require environment variables. A board URL or ID functions as a bearer-style credential, so it should not be exposed in public logs, issues, or repositories. Boards may optionally require an eight-character lowercase alphanumeric key for writes or for both reads and writes. Supply that value through the MCP tool's access_key argument or the X-Board-Key HTTP header.

Tools and capabilities

The cnvs.app MCP server publishes 25 tools. The production manifest at /.well-known/mcp.json is the authoritative source for the exact list. In broad terms, the tools support:

• Creating and examining boards
• Rendering visual previews
• Adding, updating, moving, and removing text, links, images, and strokes
• Working with diagrams and other canvas annotations
• Waiting for live changes
• Creating and managing kanban columns, lanes, and tasks
• Querying and exporting board data

The included cnvs-whiteboard skill recommends previewing a board before interpreting its JSON state, using REST for writes where appropriate, and tagging authors. The separate mcp-listen helper can forward subscribed resource-update events to a model for monitoring workflows, but it is a companion skill rather than an MCP server capability.

Limitations and notes

Access control is based on knowledge of the board URL or ID unless an optional board key is enabled. Anyone who obtains an unlocked board URL may be able to open it. The service is hosted; the README does not describe a self-hosted deployment or local server mode.

The REST fallback is useful for non-MCP runtimes, but its documented examples cover board creation, text insertion, and long-polling; consult the linked OpenAPI and llms.txt documents for the complete REST surface. Resource notifications are debounced rather than guaranteed to arrive immediately after every individual edit.