
cnvs.app
Zero-auth collaborative whiteboard that lets AI agents and humans draw on the same canvas in real time. Exposes ten MCP tools for creating boards, adding text, links, images, strokes, and Mermaid diagrams, plus moving and erasing elements. Supports resource subscriptions over SSE so agents get notified when humans edit the board, with debounced updates after activity settles. Ships with two Agent Skills: one that teaches Claude how to diagram and react to changes, another that pumps MCP push notifications into Claude Code's Monitor tool. Falls back to REST for runtimes without MCP support. Each board ID is the access key, no signup required.
- tools
- 25
- transport
- HTTP
- last updated
- Jun 15, 2026
Install
From registry metadata$ npx add-mcp https://cnvs.app/mcp --name whiteboardRun in your terminal. add-mcp asks which agents to add it to (Claude Code, Codex, Cursor and more). Add -g to install it for every project.
Review the command, arguments and environment values before installing. MCP servers run with your local permissions.
Other ways
Claude Code
$ claude mcp add --transport http whiteboard https://cnvs.app/mcpRun in your terminal. Add --scope user to make it available in every project.
Tools
Verified live · 25 toolsVerified live against the running server on Nov 6, 2026.
open_boardALWAYS 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...2 params
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...
access_keystringurl_or_id*stringcreate_boardCreate 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'`...6 params
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'`...
authorstringautolayoutbooleancontentobjectlockstringwrite · allmodestringdraw · todotemplatestringkanban · sprint · bugsget_boardFull 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 EX...2 params
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 EX...
access_keystringboard_id*stringget_previewCompact 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 wheth...2 params
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 wheth...
access_keystringboard_id*stringadd_textCreate 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 nod...11 params
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 nod...
access_keystringauthorstringboard_id*stringcolorstringcontent*stringdiagrambooleanidstringpostitbooleanwidthnumberx*numbery*numberadd_linkDrop 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).6 params
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).
access_keystringauthorstringboard_id*stringurl*stringx*numbery*numberadd_imagePlace 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. The bytes are header-checked (the leading bytes must be PNG/J...10 params
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. The bytes are header-checked (the leading bytes must be PNG/J...
access_keystringauthorstringboard_id*stringdata_url*stringheight*numberidstringthumb_data_urlstringwidth*numberx*numbery*numberdraw_strokeDraw 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...6 params
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...
access_keystringauthorstringboard_id*stringcolorstringidstringpoints*valuemoveReposition 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` d...6 params
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` d...
access_keystringboard_id*stringid*stringkindstringtext · link · line · imagex*numbery*numbereraseDelete 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...4 params
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...
access_keystringboard_id*stringid*stringkind*stringtext · line · imagewait_for_updateLong-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'...3 params
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'...
access_keystringboard_id*stringtimeout_msnumberset_board_modeChoose 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 t...4 params
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 t...
access_keystringboard_id*stringmode*stringdraw · todotemplatestringcreate_columnAdd 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...7 params
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...
access_keystringauthorstringboard_id*stringcolorstringlaneintegersortnumbertitle*stringupdate_columnRename, 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.8 params
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.
access_keystringauthorstringboard_id*stringcolorstringid*stringlaneintegersortnumbertitlestringdelete_columnDelete a kanban column by id. Tasks in the column are removed with it. Get the id from `list_tasks`.3 params
Delete a kanban column by id. Tasks in the column are removed with it. Get the id from `list_tasks`.
access_keystringboard_id*stringid*stringcreate_taskCreate 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` i...11 params
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` i...
access_keystringassigneestringauthorstringboard_id*stringcolumn_id*stringdescriptionstringdonebooleandue_datestringname*stringprioritystringH · M · Lsortnumberupdate_taskUpdate 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...12 params
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...
access_keystringassigneestringauthorstringboard_id*stringcolumn_idstringdescriptionstringdonebooleandue_datestringid*stringnamestringprioritystringH · M · Lsortnumbermove_taskMove 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.5 params
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.
access_keystringboard_id*stringcolumn_id*stringid*stringsort*numberdelete_taskDelete a task (card) by id. Get the id from `list_tasks`.3 params
Delete a task (card) by id. Get the id from `list_tasks`.
access_keystringboard_id*stringid*stringlist_tasksRead 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). Us...2 params
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). Us...
access_keystringboard_id*stringset_laneSet (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 share...5 params
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 share...
access_keystringauthorstringboard_id*stringlane*integertitlestringset_column_widthSet 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`.3 params
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`.
access_keystringboard_id*stringwidth*numbercreate_tasksBulk-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`, `s...4 params
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`, `s...
access_keystringauthorstringboard_id*stringtasks*arrayquery_tasksRead 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 →...8 params
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 →...
access_keystringassigneestringboard_id*stringdonebooleandue_afterstringdue_beforestringoverduebooleanprioritystringH · M · Lexport_tasksExport 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>...3 params
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>...
access_keystringboard_id*stringformatstringmarkdown · csvSponsors
Readme
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
Details
- Repository
- github.com/lksrz/cnvs-whiteboard-skills
- Website
- cnvs.app
- Transport
- HTTP
- Registry
- MCP registry, active
- Resources
- 3
- Tools verified
- Nov 6, 2026