cnvs.app

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by lksrz · JavaScript

Real-time collaborative whiteboard — AI agents and humans edit the same board live over MCP.

app.cnvs/whiteboard MCP Server

The app.cnvs/whiteboard MCP server provides real-time collaborative whiteboard access over MCP. It enables AI agents and humans to edit the same board live, including reading, writing, drawing, diagramming, and subscribing to live human edits. A REST fallback is also available for board operations.

🛠️ Key Features

Real-time collaborative whiteboard for shared canvas edits
AI agents can read, write, draw, diagram, and subscribe to live human edits
Supports hosted MCP server and a REST fallback
MCP endpoint: https://cnvs.app/mcp
Protocol: 2025-06-18 (Streamable HTTP)

🚀 Use Cases

Agent-driven editing of a shared whiteboard with live human updates
Collaborative diagram creation with synchronized subscriptions

⚡ Developer Benefits

MCP discovery via cnvs-whiteboard-skills
Works with Claude Code, Claude Desktop, Cursor, OpenCode/OpenAI Codex, Aider (MCP plugin), and Hermes-family agents

⚠️ Limitations

No authentication; access uses the board ID (“the acces” in provided excerpt)

Captured live from the server via tools/list.

open_board

ALWAYS call this first when given a board URL or ID. Resolves the canonical board id and auto-creates the board row if it does not exist yet. Returns a summary (item counts, authors). After this, call BOTH `get_preview` and `get_board` before editing so you can see the layout visually AND know the exact ids/coordinates — do not skip `get_preview`, otherwise you will place new items blindly on top of existing ones.

Parameters2

url_or_id	string	required	Full board URL (https://cnvs.app/#<id>) or bare UUID.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "url_or_id": {
      "type": "string",
      "description": "Full board URL (https://cnvs.app/#<id>) or bare UUID."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "url_or_id"
  ]
}

create_board

Create a fresh board in ONE call — optionally pre-filled with content, auto-laid-out, and/or PIN-locked at create time. Mirrors the extended `POST /api/boards` REST body exactly (same server-side implementation). With no arguments it returns a blank draw board; `mode: 'todo'` (+ optional `template`) seeds a kanban board. `content` imports initial items atomically: everything is validated FIRST and the board is created only if every item passes — on any invalid item you get a structured error naming its kind + index and NOTHING is created. `autolayout: true` (draw mode) fills in x/y for texts/images that omit them (deterministic masonry grid; explicit coordinates are never touched). `lock: 'write'|'all'` locks the board atomically with creation and returns the plaintext `access_key` ONCE — there is no recovery. The response's `imported` counts confirm what was created, and `embed_url` (the `?embed=1#<id>` iframe view) is returned for any board readable without a key — it is omitted for `lock:'all'` boards, whose embed frame can't read the board anonymously. Prefer this over open_board + N per-item calls when you are building a whole board from scratch.

Parameters6

mode	string	optional	Board mode. Defaults to 'draw'.
template	string	optional	Starter column set when mode is 'todo' and content.columns is empty/absent. Defaults to 'kanban'.
content	object	optional	Initial board content, applied atomically at create time. Draw mode: `texts` [{x?, y?, content, color?, width?, postit?, diagram?, kind?}], `lines` [{points, color?, anchors?}] (alias `strokes`), `images` [{x?, y?, dataUrl, width, height}]. Todo mode: `columns` [{title, lane?, color?}] (array order = sort order), `tasks` [{columnIndex, name, description?, due_date?, priority?, assignee?, done?, color?}] (columnIndex indexes into content.columns, or into the template-seeded columns when content.columns is empty), `lanes` [{lane, title}], `colWidth`. Kanban structures with a non-todo mode (or draw items with mode 'todo') are rejected with `content_mode_mismatch`. The combined input arrays may contain at most 40 entries. At most 10 lane-title entries are accepted and every title must reference a lane used by a created column. Standard per-board quotas also apply. A valid X-Import-Token selects higher REST/MCP and board-create rate tiers, but never changes these content limits.
autolayout	boolean	optional	Draw mode only: fill x/y for texts/images that omit them (deterministic masonry). Without it, items missing coordinates are rejected. No-op in todo mode.
lock	string	optional	PIN-lock the board atomically at create time; the plaintext key is returned ONCE as `access_key`.
author	string	optional	Author tag stamped on every created item (e.g. 'ai:plai'). Defaults to 'ai:import'.

Raw schema

{
  "type": "object",
  "properties": {
    "mode": {
      "type": "string",
      "enum": [
        "draw",
        "todo"
      ],
      "description": "Board mode. Defaults to 'draw'."
    },
    "template": {
      "type": "string",
      "enum": [
        "kanban",
        "sprint",
        "bugs"
      ],
      "description": "Starter column set when mode is 'todo' and content.columns is empty/absent. Defaults to 'kanban'."
    },
    "content": {
      "type": "object",
      "description": "Initial board content, applied atomically at create time. Draw mode: `texts` [{x?, y?, content, color?, width?, postit?, diagram?, kind?}], `lines` [{points, color?, anchors?}] (alias `strokes`), `images` [{x?, y?, dataUrl, width, height}]. Todo mode: `columns` [{title, lane?, color?}] (array order = sort order), `tasks` [{columnIndex, name, description?, due_date?, priority?, assignee?, done?, color?}] (columnIndex indexes into content.columns, or into the template-seeded columns when content.columns is empty), `lanes` [{lane, title}], `colWidth`. Kanban structures with a non-todo mode (or draw items with mode 'todo') are rejected with `content_mode_mismatch`. The combined input arrays may contain at most 40 entries. At most 10 lane-title entries are accepted and every title must reference a lane used by a created column. Standard per-board quotas also apply. A valid X-Import-Token selects higher REST/MCP and board-create rate tiers, but never changes these content limits."
    },
    "autolayout": {
      "type": "boolean",
      "description": "Draw mode only: fill x/y for texts/images that omit them (deterministic masonry). Without it, items missing coordinates are rejected. No-op in todo mode."
    },
    "lock": {
      "type": "string",
      "enum": [
        "write",
        "all"
      ],
      "description": "PIN-lock the board atomically at create time; the plaintext key is returned ONCE as `access_key`."
    },
    "author": {
      "type": "string",
      "description": "Author tag stamped on every created item (e.g. 'ai:plai'). Defaults to 'ai:import'."
    }
  }
}

get_board

Full structured JSON state of a board: texts (id, x, y, content, color, width, postit, author), strokes (id, points, color, author), images (id, x, y, width, height, dataUrl, thumbDataUrl, author; heavy base64 >8 kB elided to dataUrl:null, tiny images inlined). Use this for EXACT ids/coordinates/content (needed for `move`, `erase`, editing a text by id). For visual layout (where is empty space? what overlaps?) call `get_preview` instead — it's much cheaper for spatial reasoning than a huge JSON dump.

Parameters2

board_id	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

get_preview

Compact schematic SVG render of the board (typically a few kB even for dense boards). Returns both an image/svg+xml content block (you can SEE it) and the raw SVG text. CALL THIS any time you need to understand where things are — before placing new items, before deciding whether the canvas is crowded, before picking a free region. AI-authored items get a purple border so you can tell which contributions were yours. For precise text content prefer `get_board`.

Parameters2

board_id	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

add_text

Create a NEW text node, or update an existing one (pass the same `id` to overwrite content/position in place — preferred over creating a duplicate). Supports cnvs markup (Markdown-ish) and Mermaid diagrams in the content. When using Mermaid, the ENTIRE content of this text node must be a single Mermaid diagram (one ```mermaid fenced block and nothing else — no heading, no prose before or after). If you need prose + a diagram, create two separate text nodes. `postit: true` renders as a yellow sticky; `diagram: true` renders as a framed box (2px border in the text colour, centred text) — the two are mutually exclusive. Coordinates are in board-world pixels, +x right, +y DOWN; pick a spot that does not overlap existing items (check `get_preview` first). Default width auto-fits content up to ~320 px; pass `width` for explicit wrapping (160–4096). Keep content under 100 000 chars.

Parameters11

board_id	string	required
id	string	optional	Optional stable id; generated when omitted.
x	number	required
y	number	required
content	string	required
color	string	optional	Named ink only (no hex). Accepted (case-insensitive): 'auto'/''/'black'/omitted for theme-aware ink, or 'red', 'blue', 'green', 'orange', 'yellow', 'pink', 'purple', 'maroon', 'brown', 'gray', 'lightgray', 'teal', 'sage', 'sky', 'lavender'. Anything else (including a literal hex) silently clamps to auto.
width	number	optional	Explicit width in px (160–4096).
postit	boolean	optional
diagram	boolean	optional	Render as a framed diagram box (2px border in the text colour, centred text). Mutually exclusive with postit.
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string",
      "description": "Optional stable id; generated when omitted."
    },
    "x": {
      "type": "number"
    },
    "y": {
      "type": "number"
    },
    "content": {
      "type": "string"
    },
    "color": {
      "type": "string",
      "description": "Named ink only (no hex). Accepted (case-insensitive): 'auto'/''/'black'/omitted for theme-aware ink, or 'red', 'blue', 'green', 'orange', 'yellow', 'pink', 'purple', 'maroon', 'brown', 'gray', 'lightgray', 'teal', 'sage', 'sky', 'lavender'. Anything else (including a literal hex) silently clamps to auto."
    },
    "width": {
      "type": "number",
      "description": "Explicit width in px (160–4096)."
    },
    "postit": {
      "type": "boolean"
    },
    "diagram": {
      "type": "boolean",
      "description": "Render as a framed diagram box (2px border in the text colour, centred text). Mutually exclusive with postit."
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "x",
    "y",
    "content"
  ]
}

add_link

Drop a URL capsule onto the board — rendered as a clickable pill showing the hostname. Use this instead of `add_text` when the node is just a link; the capsule styling signals clickability to humans. Same coordinate rules as `add_text` (+x right, +y down).

Parameters6

board_id	string	required
x	number	required
y	number	required
url	string	required
author	string	optional
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "x": {
      "type": "number"
    },
    "y": {
      "type": "number"
    },
    "url": {
      "type": "string"
    },
    "author": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "x",
    "y",
    "url"
  ]
}

add_image

Place a raster or SVG image on the board at (x, y) with explicit width/height in board pixels. `data_url` MUST be a `data:image/(png|jpeg|gif|webp|svg+xml);base64,...` string ≤ ~900 kB; hosted URLs are not accepted. Strongly recommended: also pass a tiny `thumb_data_url` (≤8 kB JPEG/PNG/WebP, ~64 px on the long edge) — it is embedded into the SVG preview so OTHER AI viewers (and you, on later `get_preview` calls) can actually see the image instead of a placeholder box.

Parameters10

board_id	string	required
id	string	optional
x	number	required
y	number	required
width	number	required
height	number	required
data_url	string	required
thumb_data_url	string	optional
author	string	optional
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "x": {
      "type": "number"
    },
    "y": {
      "type": "number"
    },
    "width": {
      "type": "number"
    },
    "height": {
      "type": "number"
    },
    "data_url": {
      "type": "string"
    },
    "thumb_data_url": {
      "type": "string"
    },
    "author": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "x",
    "y",
    "width",
    "height",
    "data_url"
  ]
}

draw_stroke

Draw a freehand stroke on the board. Use for arrows, underlines, connector lines, annotations, or simple shapes — a straight line needs two points, a rough circle wants ~20. Stroke width is fixed at 3 px; `color` is a NAME, not hex (case-insensitive): 'auto'/''/'black'/omitted for theme-aware ink, or 'red', 'blue', 'green', 'orange', 'yellow', 'pink', 'purple', 'maroon', 'brown', 'gray', 'lightgray', 'teal', 'sage', 'sky', 'lavender' — anything else (including a literal hex like '#ff0000') silently clamps to auto. Accepts three equivalent point formats — pick whichever your MCP client serialises cleanly: nested `[[x,y],[x,y],...]`, flat `[x1,y1,x2,y2,...]`, or a JSON string of either. Some clients (Claude Code as of 2026-04) drop nested arrays during tool-call serialisation, so prefer the flat form or the JSON-string form when in doubt. To delete a stroke later, use `erase` with `kind: 'line'` and the id returned here.

Parameters6

board_id	string	required
id	string	optional
points	any	required	Points as [[x,y],...], flat [x1,y1,x2,y2,...], or a JSON string of either.
color	string	optional
author	string	optional
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "points": {
      "description": "Points as [[x,y],...], flat [x1,y1,x2,y2,...], or a JSON string of either."
    },
    "color": {
      "type": "string"
    },
    "author": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "points"
  ]
}

move

Reposition an existing item to a new (x, y) without retyping its content. Works for every item kind: `text` and `link` set the top-left to (x, y); `line` translates every point so the stroke's bounding box top-left lands at (x, y); `image` sets the top-left like text. `kind` defaults to `text` for backward compat with older callers. Find the id + kind via `get_board`. Prefer `move` over re-creating an item when only the location changes — it preserves the id, content, author and avoids a round-trip of base64 bytes for images.

Parameters6

board_id	string	required
id	string	required
kind	string	optional	Item kind. Defaults to `text`.
x	number	required
y	number	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "kind": {
      "type": "string",
      "enum": [
        "text",
        "link",
        "line",
        "image"
      ],
      "description": "Item kind. Defaults to `text`."
    },
    "x": {
      "type": "number"
    },
    "y": {
      "type": "number"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id",
    "x",
    "y"
  ]
}

erase

Delete a single item by id. `kind` MUST match the item type: 'text' for text nodes, 'line' for freehand strokes, 'image' for images — the wrong kind silently targets the wrong table and is a common mistake. Get the id + type from `get_board` (texts[], lines[], images[]). There is no bulk/erase-all tool: loop if you need to delete multiple items.

Parameters4

board_id	string	required
id	string	required
kind	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "kind": {
      "type": "string",
      "enum": [
        "text",
        "line",
        "image"
      ]
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id",
    "kind"
  ]
}

wait_for_update

Long-poll: blocks until the next edit lands on this board, then returns. WHEN TO CALL THIS: if your MCP client does NOT surface `notifications/resources/updated` events from `resources/subscribe` back to the model (most chat clients do not — they receive the SSE event but don't inject it into your context), this tool is how you 'wait for the human' inside a single turn. Typical flow: you draw / write what you were asked to, then instead of ending your turn you call `wait_for_update(board_id)`. When the human adds, moves, or erases something, the call returns and you refresh with `get_preview` / `get_board` and continue the collaboration. Great for turn-based interactions (games like tic-tac-toe, brainstorming where you respond to each sticky the user drops, sketch-and-feedback loops, etc.). If your client DOES deliver resource notifications natively, prefer `resources/subscribe` — it's cheaper and has no timeout ceiling. BEHAVIOUR: resolves ~3 s after the edit burst settles (same debounce as the push notifications — this is intentional so drags and long strokes collapse into one wake-up). Returns `{ updated: true, timedOut: false }` on a real edit, or `{ updated: false, timedOut: true }` if nothing happened within `timeout_ms`. On timeout, just call it again to keep waiting; chaining calls is cheap. `timeout_ms` is clamped to [1000, 55000]; default 25000 (leaves headroom under typical 60 s proxy timeouts).

Parameters3

board_id	string	required
timeout_ms	number	optional
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "timeout_ms": {
      "type": "number"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

set_board_mode

Choose whether this board is a freeform whiteboard ('draw', the default) or a kanban task board ('todo'). Mode is switchable WHENEVER the board is empty of real content: drawings (text/strokes/images) and tasks. Empty or seeded columns DON'T count (switching to 'draw' clears them), so a cleared board can be switched again, and you can flip draw<->todo freely until the first stroke/text/image or task lands. Setting 'todo' auto-seeds three starter columns (To do / In progress / Done). Returns `{ mode, columns }`. Use the task/column tools (`create_task`, `create_column`, …) once the board is in 'todo' mode.

Parameters4

board_id	string	required
mode	string	required	Board mode.
template	string	optional	Optional starter column template when mode is 'todo': 'kanban' (To do / In progress / Done, the default), 'sprint' (Backlog / Sprint / Review / Done), or 'bugs' (Triage / Confirmed / In progress / Fixed). Unknown/omitted falls back to 'kanban'.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "mode": {
      "type": "string",
      "enum": [
        "draw",
        "todo"
      ],
      "description": "Board mode."
    },
    "template": {
      "type": "string",
      "description": "Optional starter column template when mode is 'todo': 'kanban' (To do / In progress / Done, the default), 'sprint' (Backlog / Sprint / Review / Done), or 'bugs' (Triage / Confirmed / In progress / Fixed). Unknown/omitted falls back to 'kanban'."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "mode"
  ]
}

create_column

Add a kanban column (swimlane) to a 'todo' board. Generates and returns a stable column id. `sort` is a float ordering key (ascending); omit to default to 0. `lane` is an integer row index for multi-row layouts (defaults to 0). `color` is an optional title color ('red' / 'blue' / 'green', or 'auto' / omit for default). To rename, reorder, recolor or move between lanes later use `update_column`.

Parameters7

board_id	string	required
title	string	required
sort	number	optional	Float ordering key (ascending). Defaults to 0.
lane	integer	optional	Row index for multi-row layouts. Defaults to 0.
color	string	optional	Title color: 'red', 'blue', 'green', or 'auto' (default).
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "title": {
      "type": "string"
    },
    "sort": {
      "type": "number",
      "description": "Float ordering key (ascending). Defaults to 0."
    },
    "lane": {
      "type": "integer",
      "description": "Row index for multi-row layouts. Defaults to 0."
    },
    "color": {
      "type": "string",
      "description": "Title color: 'red', 'blue', 'green', or 'auto' (default)."
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "title"
  ]
}

update_column

Rename, reorder, recolor or move an existing kanban column. Requires the column `id` (from `list_tasks`). Pass `title`, `sort`, `lane` and/or `color` to change them.

Parameters8

board_id	string	required
id	string	required
title	string	optional
sort	number	optional	Float ordering key (ascending).
lane	integer	optional	Row index for multi-row layouts.
color	string	optional	Title color: 'red', 'blue', 'green', or 'auto' (default).
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "title": {
      "type": "string"
    },
    "sort": {
      "type": "number",
      "description": "Float ordering key (ascending)."
    },
    "lane": {
      "type": "integer",
      "description": "Row index for multi-row layouts."
    },
    "color": {
      "type": "string",
      "description": "Title color: 'red', 'blue', 'green', or 'auto' (default)."
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id"
  ]
}

delete_column

Delete a kanban column by id. Tasks in the column are removed with it. Get the id from `list_tasks`.

Parameters3

board_id	string	required
id	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id"
  ]
}

create_task

Create a task (card) in a column on a 'todo' board. Generates and returns a stable task id. `column_id` must reference an existing column (see `list_tasks`). `description` is free-form prose stored on the card; `priority` is one of 'H' | 'M' | 'L' (omit for none); `due_date` is an ISO 8601 date string; `assignee` is free text (name / initials / email). `sort` is a float ordering key within the column (ascending), defaulting to 0.

Parameters11

board_id	string	required
column_id	string	required
name	string	required
description	string	optional
due_date	string	optional	ISO 8601 date.
priority	string	optional	High / Medium / Low. Omit for none.
assignee	string	optional
done	boolean	optional	Whether the task is completed (checked off). Defaults to false.
sort	number	optional	Float ordering key within the column. Defaults to 0.
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "column_id": {
      "type": "string"
    },
    "name": {
      "type": "string"
    },
    "description": {
      "type": "string"
    },
    "due_date": {
      "type": "string",
      "description": "ISO 8601 date."
    },
    "priority": {
      "type": "string",
      "enum": [
        "H",
        "M",
        "L"
      ],
      "description": "High / Medium / Low. Omit for none."
    },
    "assignee": {
      "type": "string"
    },
    "done": {
      "type": "boolean",
      "description": "Whether the task is completed (checked off). Defaults to false."
    },
    "sort": {
      "type": "number",
      "description": "Float ordering key within the column. Defaults to 0."
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "column_id",
    "name"
  ]
}

update_task

Update an existing task by `id` (from `list_tasks`). Pass only the fields you want to change: `name`, `description`, `due_date`, `priority` ('H'|'M'|'L'), `assignee`, `done` (true once completed), `column_id` (to reassign), `sort`. To move a card between columns while setting its order, `move_task` is the dedicated tool.

Parameters12

board_id	string	required
id	string	required
name	string	optional
description	string	optional
due_date	string	optional	ISO 8601 date.
priority	string	optional
assignee	string	optional
done	boolean	optional	Whether the task is completed (checked off).
column_id	string	optional
sort	number	optional
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "name": {
      "type": "string"
    },
    "description": {
      "type": "string"
    },
    "due_date": {
      "type": "string",
      "description": "ISO 8601 date."
    },
    "priority": {
      "type": "string",
      "enum": [
        "H",
        "M",
        "L"
      ]
    },
    "assignee": {
      "type": "string"
    },
    "done": {
      "type": "boolean",
      "description": "Whether the task is completed (checked off)."
    },
    "column_id": {
      "type": "string"
    },
    "sort": {
      "type": "number"
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id"
  ]
}

move_task

Move a task to a column at a given sort position — the kanban drag-and-drop primitive. `column_id` is the destination column and `sort` its float order key (ascending) within that column.

Parameters5

board_id	string	required
id	string	required
column_id	string	required
sort	number	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "column_id": {
      "type": "string"
    },
    "sort": {
      "type": "number"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id",
    "column_id",
    "sort"
  ]
}

delete_task

Delete a task (card) by id. Get the id from `list_tasks`.

Parameters3

board_id	string	required
id	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "id": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "id"
  ]
}

list_tasks

Read the full kanban state of a 'todo' board: `{ mode, columns, tasks }`, both ordered by their `sort` key (ascending). Each task carries its hot fields (name, due_date, priority, assignee, done, column_id, sort) plus an opaque `content` JSON string (holds the description). Use this to get exact column/task ids before updating, moving or deleting.

Parameters2

board_id	string	required
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

set_lane

Set (or clear) the title of a kanban row (lane). Lanes group columns into horizontal swimlanes; a lane is identified by its integer `lane` index (the same index columns carry). Pass a `title` to name the row, or an empty string to clear it. Read current lane titles + the shared column width via `list_tasks`.

Parameters5

board_id	string	required
lane	integer	required	Row index (>= 0).
title	string	optional	Row title; empty string clears it.
author	string	optional	Author tag, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "lane": {
      "type": "integer",
      "description": "Row index (>= 0)."
    },
    "title": {
      "type": "string",
      "description": "Row title; empty string clears it."
    },
    "author": {
      "type": "string",
      "description": "Author tag, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "lane"
  ]
}

set_column_width

Set the shared kanban column width in pixels for a 'todo' board (all columns share one width). Clamped to [200, 480]. Read the current value as `colWidth` from `list_tasks`.

Parameters3

board_id	string	required
width	number	required	Column width in px, clamped to [200, 480].
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "width": {
      "type": "number",
      "description": "Column width in px, clamped to [200, 480]."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "width"
  ]
}

create_tasks

Bulk-create multiple task cards in one call — far cheaper than calling `create_task` N times. Pass `tasks`: an array of task objects, each with `column_id` (required) + the same fields `create_task` accepts (`name`, `description`, `due_date`, `priority`, `assignee`, `done`, `sort`). Returns the array of created ids in order. Stops at the first invalid item and reports its index; items before it are still created (not transactional).

Parameters4

board_id	string	required
tasks	array	required	Array of task objects to create.
author	string	optional	Author tag applied to every task, defaults to ai:claude.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "tasks": {
      "type": "array",
      "description": "Array of task objects to create.",
      "items": {
        "type": "object",
        "properties": {
          "column_id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          },
          "description": {
            "type": "string"
          },
          "due_date": {
            "type": "string",
            "description": "ISO 8601 date."
          },
          "priority": {
            "type": "string",
            "enum": [
              "H",
              "M",
              "L"
            ]
          },
          "assignee": {
            "type": "string"
          },
          "done": {
            "type": "boolean"
          },
          "sort": {
            "type": "number"
          }
        },
        "required": [
          "column_id",
          "name"
        ]
      }
    },
    "author": {
      "type": "string",
      "description": "Author tag applied to every task, defaults to ai:claude."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id",
    "tasks"
  ]
}

query_tasks

Read tasks from a 'todo' board with server-side filtering — handy for 'what's overdue?' / 'what's assigned to X?' without pulling the whole board. All filters are optional and AND together: `assignee` (exact match), `priority` ('H'|'M'|'L'), `done` (boolean), `overdue` (true → due_date strictly before today, not done), `due_before` / `due_after` (ISO date window on due_date). Returns `{ boardId, mode, tasks }` — tasks ordered by sort, each with the same fields as `list_tasks`.

Parameters8

board_id	string	required
assignee	string	optional	Exact-match assignee filter.
priority	string	optional
done	boolean	optional
overdue	boolean	optional	Only tasks past due and not done.
due_before	string	optional	ISO date; due_date < this.
due_after	string	optional	ISO date; due_date > this.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "assignee": {
      "type": "string",
      "description": "Exact-match assignee filter."
    },
    "priority": {
      "type": "string",
      "enum": [
        "H",
        "M",
        "L"
      ]
    },
    "done": {
      "type": "boolean"
    },
    "overdue": {
      "type": "boolean",
      "description": "Only tasks past due and not done."
    },
    "due_before": {
      "type": "string",
      "description": "ISO date; due_date < this."
    },
    "due_after": {
      "type": "string",
      "description": "ISO date; due_date > this."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

export_tasks

Export a 'todo' board's columns + tasks as a single text document. `format` is 'markdown' (a checklist grouped by column, the default) or 'csv' (one row per task with column/name/priority/assignee/due_date/done). Returns the rendered text. Same data as the GET /api/boards/<id>/tasks.md and tasks.csv REST endpoints.

Parameters3

board_id	string	required
format	string	optional	Output format. Defaults to 'markdown'.
access_key	string	optional	6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock.

Raw schema

{
  "type": "object",
  "properties": {
    "board_id": {
      "type": "string"
    },
    "format": {
      "type": "string",
      "enum": [
        "markdown",
        "csv"
      ],
      "description": "Output format. Defaults to 'markdown'."
    },
    "access_key": {
      "type": "string",
      "description": "6-char board access key (a-z, 0-9) when the board is locked. Equivalent to setting the `X-Board-Key` HTTP header on the JSON-RPC POST. Omit for unlocked boards. Obtain via POST /api/boards/<id>/lock."
    }
  },
  "required": [
    "board_id"
  ]
}

README.md13 KBView on GitHub

cnvs-whiteboard-skills

Agent Skills + MCP server discovery for cnvs.app — the free, no-signup real-time collaborative whiteboard. Any AI agent can read, write, draw, diagram, and subscribe to live human edits on a shared canvas, either through the hosted MCP server or the REST fallback.

Works with Claude Code, Claude Desktop, Cursor, OpenCode / OpenAI Codex, Aider (with MCP plugin), any other MCP-speaking client, and Hermes-family agents.

MCP Server

Endpoint: https://cnvs.app/mcp (Streamable HTTP, protocol 2025-06-18, no auth — the board ID is the access key).

Registered in the official MCP Registry as app.cnvs/whiteboard.

Capabilities

Tools (25): board creation and inspection; visual previews; text, link, image, and stroke editing; movement and deletion; live-update waits; and complete kanban column, lane, task, query, and export workflows. The exact production list is published in /.well-known/mcp.json. State-changing operations also have REST mirrors under https://cnvs.app/api/boards/<id>/… for runtimes that cannot speak MCP.
Resources (3): cnvs://board/{id}/state.json (full snapshot), cnvs://board/{id}/preview.svg (visual render), and cnvs://board/{id}/tasks.json (kanban state). All three are subscribable.
Subscriptions: resources/subscribe supported with notifications/resources/updated pushed over SSE, debounced ~3 s after activity settles.
Live machine-readable manifests: /quotas.json, /openapi.json, /llms.txt, /.well-known/mcp.json, /.well-known/mcp/server.json.

Installation

Codex / ChatGPT and Cursor packages

This repository is the public source package for both marketplace integrations:

.codex-plugin/plugin.json and .mcp.json describe the Codex / ChatGPT plugin.
.cursor-plugin/plugin.json and mcp.json describe the Cursor plugin.
SUBMISSION.md and CURSOR-MARKETPLACE.md contain the prepared listing copy, disclosures, reviewer flows, and submission checklists.

Both packages connect only to the hosted production endpoint; there is no local server process or secret to configure.

Claude Desktop / Cursor / any MCP client

One-line config — add this to your client's mcpServers object:

json

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

Claude Code CLI

bash

claude mcp add --transport http cnvs https://cnvs.app/mcp

REST-only (no MCP client)

bash

# Create a board
curl -X POST https://cnvs.app/api/boards

# Add text
curl -X POST https://cnvs.app/api/boards/<id>/texts \
  -H 'Content-Type: application/json' \
  -d '{"x":100,"y":200,"content":"# Hello","author":"ai:myagent"}'

# Long-poll for live changes
curl "https://cnvs.app/api/boards/<id>/wait?timeout_ms=25000"

Full REST reference: /llms.txt, /openapi.json.

Access model

There is no account or OAuth flow. A board URL or board ID is a bearer-style access credential: anyone who knows an unlocked board URL can open it. Boards can optionally require an 8-character lowercase alphanumeric access key for writes or for both reads and writes; legacy 6-character keys remain accepted. Pass a key only through the MCP tool's access_key argument or the X-Board-Key HTTP header.

Do not paste private board URLs or access keys into public issues, logs, or repositories.

Useful prompts

Create a fresh whiteboard for our brainstorming session and return its URL.
Open this cnvs.app board, inspect its preview, and summarize the layout.
Turn this list into a shared kanban board with priorities and owners.

Skills included

Two related Agent Skills live in this repo, published under the agentskills.io open standard so they work in any compatible runtime. Install them into ~/.claude/skills/ to teach the agent how to use the MCP server well (preview-before-JSON, REST-over-MCP for writes, author-tag conventions, subscription-then-react loop).

`cnvs-whiteboard/` — PRIMARY

Teaches an AI agent how to collaborate on a cnvs.app board in real time:

Read the shared canvas state
Draw / diagram / flowchart / annotate — add, update, move, and delete text, links, sticky notes, strokes, images, and Mermaid diagrams (flowcharts, sequence / class / ER diagrams, mind maps, gantt charts, concept maps)
Render the SVG preview when the board contains drawings
Subscribe to live human edits via MCP, react via REST

Activates on any cnvs.app board reference (URL https://cnvs.app/#<id>, cnvs://board/<id>/..., or a bare board ID) or phrases like "collaborate on / draw / diagram / annotate / watch a shared whiteboard or canvas."

`mcp-listen/` — HELPER (v0.3.0)

Push-to-model pump for Streamable-HTTP MCP servers with capabilities.resources.subscribe: true. Opens a session, subscribes to the resource URIs the caller hands over, and emits one JSON line per notifications/resources/updated event on stdout — designed to be wrapped by Claude Code's Monitor tool so every server push becomes an in-chat notification (no polling, no log tailing).

Helper-only activation since v0.3. Triggers only when the caller — a user or another skill — has supplied both an MCP server URL and at least one resource URI. Does NOT auto-activate from generic phrasing like "watch this file" or "stay in the loop". cnvs-whiteboard is the canonical caller and delegates its push channel here.

Output split since v0.3. Only the actionable resource_updated event reaches stdout by default. Connection / subscription / heartbeat / transient-error events go to stderr so a wrapping Monitor doesn't fire on the listener's own bookkeeping. Pass --verbose (or -v) to merge everything onto stdout for debugging or single-channel logging (legacy v0.2 behavior).

Registry status. Intentionally not listed in centralised skill registries yet. Current registry pipelines (e.g. majiayu000/claude-skill-registry-core as of 2026-05-03) archive only SKILL.md + generated metadata; they do not mirror bundled scripts/** or package.json, so an entry for mcp-listen would publish a broken skill. It will be (re-)submitted once core registries support directory-style skill archival with bundled-file mirroring and security scanning — see PR majiayu000/claude-skill-registry-core#40 for the directory-archive primitive that just landed and the open question on bundled-script scanning. Until then, install it via curl from cnvs.app (below) or git clone this repo.

Install the skills

bash

# cnvs-whiteboard (SKILL.md only — no deps)
mkdir -p ~/.claude/skills/cnvs-whiteboard && cd ~/.claude/skills/cnvs-whiteboard
curl -O https://cnvs.app/cnvs-whiteboard/SKILL.md

# mcp-listen (SKILL.md + scripts/ + npm install)
mkdir -p ~/.claude/skills/mcp-listen && cd ~/.claude/skills/mcp-listen
curl -O https://cnvs.app/mcp-listen/SKILL.md \
     -O https://cnvs.app/mcp-listen/package.json \
     --create-dirs -o scripts/listen.mjs https://cnvs.app/mcp-listen/scripts/listen.mjs
npm install

Alternatively git clone this repo and cp -r .claude/skills/* ~/.claude/skills/ — the .claude/skills/ directory contains symlinks into cnvs-whiteboard/ and mcp-listen/ for Claude Code's expected layout.

Spec compliance

Both skills follow the agentskills.io spec:

name matches the containing directory name
description under 1024 characters, imperative phrasing, explicit trigger keywords
scripts/ subdirectory for bundled code (mcp-listen)
license: MIT, compatibility field declared, cross-references in each skill's "Related skills" section to prevent activation overlap

Why two skills

Earlier versions had a single page (/skill-cnvs.md on cnvs.app — now a legacy redirect). Splitting into two coherent units follows the spec's "design coherent units" best practice:

cnvs-whiteboard owns the cnvs.app-specific workflow (read / write / render / gotchas).
mcp-listen owns the generic push-to-model pattern (usable against any MCP server).

Cross-references keep them pairing cleanly: cnvs-whiteboard mentions mcp-listen as its delegated push channel; mcp-listen mentions cnvs-whiteboard as the companion for cnvs-specific work. No activation overlap in practice.

Canonical sources

Skills are also served live at:

The cnvs.app URLs are the canonical install targets for curl-based installers; this GitHub repo is the reference for aggregators that crawl public sources (skills.sh, etc.) and for users who prefer git clone.

Discovery surfaces

Live

Official MCP Registry: app.cnvs/whiteboard — browse
cnvs.app /.well-known/mcp.json — links both skills
cnvs.app /.well-known/mcp/server.json — MCP Registry entry with publisher-provided _meta.skills[]
cnvs.app /llms.txt — LLM-friendly full reference
majiayu000/claude-skill-registry-core — cnvs-whiteboard listed (PR #31 merged 2026-05-04). mcp-listen intentionally held back; see Registry status on the mcp-listen/ section above.
Lobehub (used by Hermes agent) — both skills imported; MCP server submitted

Planned / under consideration

Notes for future expansion of distribution. Not active yet — kept here so the next maintenance window doesn't have to re-discover the landscape.

majiayu000/claude-skill-registry-core — re-submit mcp-listen as a separate PR now that PR #40 (directory archives + bundled-script security scanning) is merged. scripts/listen.mjs is even hardcoded into their test assertions, so the pipeline already exercises our exact case.
daymade/claude-code-skills (vendored model) — fork, copy cnvs-whiteboard/ and mcp-listen/ directly into their tree (their layout already expects scripts//references//assets/), update marketplace.json, single PR for both skills. No bundled-files concern because the files are copied in.
VoltAgent/awesome-agent-skills (curated awesome-list, 20k ⭐) — markdown link, ≤10-word description. Their CONTRIBUTING explicitly excludes brand-new skills ("give your skill time to mature and gain users before submitting"); revisit once there's documented external usage.
sickn33/antigravity-awesome-skills (36k ⭐) — manual path: fork, add skills/<name>/SKILL.md, run npm run validate. Their  header in README suggests automated pull from upstream registries, so a successful entry on majiayu000/claude-skill-registry-core may propagate here without a separate PR — confirm before submitting twice.
agentskills/agentskills (17.8k ⭐, the spec org behind agentskills.io) — investigate whether they accept reference implementations; mcp-listen as a worked example of MCP resources/subscribe consumption could fit there.
vercel-labs/agent-skills / vercel-labs/skills — almost certainly curated, but read CONTRIBUTING before ruling out.

Skipped intentionally: anthropics/skills (curated, no community PRs); personal collections under ~100 ⭐; language-specific lists unless a relevant audience emerges.

License

MIT. See LICENSE.

Install

Tools (25)

open_boardcreate_boardget_boardget_previewadd_textadd_linkadd_imagedraw_stroke

Remote endpoint

Streamable HTTP

Hosted server - connect over the network, no local install.

url

https://cnvs.app/mcp

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "whiteboard": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://cnvs.app/mcp"
      ]
    }
  }
}

Desktop config is stdio-only; this bridges via mcp-remote. Native remote: Settings > Connectors.

app.cnvs/whiteboard MCP Server

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

open_board

create_board

get_board

get_preview

add_text

add_link

add_image

draw_stroke

move

erase

wait_for_update

set_board_mode

create_column

update_column

delete_column

create_task

update_task

move_task

delete_task

list_tasks

set_lane

set_column_width

create_tasks

query_tasks

export_tasks

cnvs-whiteboard-skills

MCP Server

Capabilities

Installation

Codex / ChatGPT and Cursor packages

Claude Desktop / Cursor / any MCP client

Claude Code CLI

REST-only (no MCP client)

Access model

Useful prompts

Skills included

cnvs-whiteboard/ — PRIMARY

mcp-listen/ — HELPER (v0.3.0)

Install the skills

Spec compliance

Why two skills

Canonical sources

Discovery surfaces

Live

Planned / under consideration

License

Install

Remote endpoint

Related servers

`cnvs-whiteboard/` — PRIMARY

`mcp-listen/` — HELPER (v0.3.0)