Take a screenshot of the current canvas and return it as an image. Requires the canvas frontend to be open in a browser. Use this to visually verify what the diagram looks like.
AI agents call get_canvas_screenshot to retrieve information from Excalidraw MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool performs a read-only operation that retrieves visual information (screenshot) from the canvas without modifying, deleting, or executing any operations. It has no persistence side effects and poses minimal risk if misused by an AI agent. The worst-case scenario would be exfiltration of diagram contents, which is a low-severity information disclosure.
From the tool's definition Tool description states: 'Take a screenshot of the current canvas and return it as an image.' This is a query/retrieval operation with no side effects—it only captures and returns visual data of the current state.
Attacks that exploit this kind of access
Take a screenshot of the current canvas and return it as an image. Requires the canvas frontend to be open in a browser. Use this to visually verify what the diagram looks like. It is categorised as a Read tool in the Excalidraw MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Excalidraw MCP Server MCP server in PolicyLayer and add a rule for get_canvas_screenshot: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Excalidraw MCP Server. Nothing to install.
get_canvas_screenshot is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_canvas_screenshot rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for get_canvas_screenshot. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
get_canvas_screenshot is provided by the Excalidraw MCP Server MCP server (kakacoding1/mcp_excalidraw). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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