Canvs MCP Server

⚠️ MANDATORY FIRST STEP - Call this tool BEFORE using any other Canvs tools! Returns comprehensive instructions for creating whiteboards: tool selection strategy, iterative workflow, and examples. Following these instructions ensures correct diagrams.

Manual fallback for creating canvas and adding elements. ⚠️ IMPORTANT: Call get_guide first and follow its instructions! Use this tool only when the user's request is not a good fit for Mermaid. If the request can be represented in Mermaid, use add_elements_from_mermaid instead. If room_id is NOT provided - creates a NEW canvas and returns url plus room_id. If the user did not explicitly mention an existing board/canvas/room, do NOT ask for a room_id; create a new canvas instead. If a previous Canvs tool result or assistant message in the same conversation contains a room_id, reuse it for follow-up requests like 'add to it' or 'same board'. If you only have a room URL, extract room_id from https://[host]/?room=[room_id] or https://[host]/gdrive?id=[room_id]. If the user refers to a previous board but no usable room_id is available, create a new canvas instead of asking for the URL by default. If room_id IS provided - adds elements to that canvas. If the canvas is displayed as an inline widget in the interface, do NOT include the url in your reply. If no widget is shown, share the url so the user can open the canvas.Use cases: wireframes, UI mockups, freeform illustrations, standalone shapes, and manual layouts that Mermaid does not cover well. Do not use this tool for diagrams that Mermaid can express. Element types: rectangle, ellipse, diamond, arrow, line, freedraw, text, image. Rich text: the text field supports limited HTML for text elements and rectangle/ellipse/diamond shape labels. Supports the rich-text plugin HTML subset: <b>/<strong>, <i>/<em>, <u>, <br>, <div>/<p>, <ul>/<ol>/<li>, <a href>, <font color>, and <span style="color, background/background-color, font-size, font-family">. Use textAlign for left/center/right alignment; avoid unsupported HTML/CSS. TEXT IN SHAPES: use containerId on text element pointing to shape id. ARROWS: Position at EDGE of source shape. Auto-bound within 30px. Colors: strokeColor, backgroundColor (hex).

Update elements on a canvas. Requires room_id from a previous Canvs tool result. Pass elements array with id and fields to update. IMPORTANT: in each update object ONLY `id` is required; all other fields are optional patch fields. Include ONLY elements that need changes; elements omitted from the request remain unchanged on the board. Prefer this tool for SMALL edits to existing diagrams (rename/move/restyle a few elements), typically after query_elements.

Delete elements from a canvas. Requires room_id from a previous Canvs tool result. Pass ids array of element IDs to delete.

Query elements on a canvas. Requires room_id from a previous Canvs tool result. Returns elements matching optional filters. Use this before update_elements when making small edits to existing diagrams. If no browser has the canvas open, returns an error — ask the user to open the canvas URL in their browser and retry.

Preferred method for creating diagram elements from Mermaid. ⚠️ IMPORTANT: Call get_guide first and follow its instructions! Use this tool for NEW diagrams and LARGE changes to existing diagrams whenever the request can be represented in Mermaid. Prefer translating the request into Mermaid instead of manually recreating it with add_elements. If room_id is NOT provided - creates a NEW canvas and returns url plus room_id. If the user did not explicitly mention an existing board/canvas/room, do NOT ask for a room_id; create a new canvas instead. If a previous Canvs tool result or assistant message in the same conversation contains a room_id, reuse it for follow-up requests like 'add to it' or 'same board'. If you only have a room URL, extract room_id from https://[host]/?room=[room_id] or https://[host]/gdrive?id=[room_id]. If the user refers to a previous board but no usable room_id is available, create a new canvas instead of asking for the URL by default. If room_id IS provided - adds diagram elements to that canvas. If the canvas is displayed as an inline widget in the interface, do NOT include the url in your reply. If no widget is shown, share the url so the user can open the canvas.Supports: flowchart, graph, flowchart-elk, sequenceDiagram, classDiagram, classDiagram-v2, stateDiagram, stateDiagram-v2, erDiagram, journey, gantt, pie, gitGraph, mindmap, timeline, C4Context, C4Container, C4Component, C4Dynamic, C4Deployment, sankey, sankey-beta, quadrantChart, xychart, xychart-beta, requirement, requirementDiagram, kanban, architecture, block, block-beta, packet, packet-beta, radar-beta, treemap, info. Example: "flowchart TD\n A[Start] --> B{Decision}\n B -->|Yes| C[OK]\n B -->|No| D[Cancel]"