Returns a comprehensive design guide for creating beautiful Excalidraw diagrams: color palette, sizing rules, layout patterns, arrow binding best practices, diagram templates, and anti-patterns. Call this before creating diagrams to produce professional results.
AI agents call read_diagram_guide 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.
This tool retrieves reference documentation (design patterns, color palette, sizing rules, templates) to inform user decisions. It is purely informational with no data modification, code execution, or destructive capability. The read semantic and lack of side effects place it clearly in the Read category with low severity.
From the tool's definition Tool name 'read_diagram_guide' and description explicitly state it 'Returns a comprehensive design guide'—a retrieval operation with no side effects. No creation, modification, deletion, or execution of external operations.
Documented attack patterns abuse exactly the kind of access read_diagram_guide gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Excalidraw MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for read_diagram_guide:
{
"version": "1",
"default": "deny",
"tools": {
"read_diagram_guide": {}
}
}read_diagram_guide is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Returns a comprehensive design guide for creating beautiful Excalidraw diagrams: color palette, sizing rules, layout patterns, arrow binding best practices, diagram templates, and anti-patterns. Call this before creating diagrams to produce professional results. 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 read_diagram_guide: 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.
read_diagram_guide 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 read_diagram_guide 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 read_diagram_guide. 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.
read_diagram_guide is provided by the Excalidraw MCP Server MCP server (yctimlin/mcp_excalidraw). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 26 Excalidraw MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
26 Excalidraw MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.