AI agents use group_elements to create or update resources in Excalidraw MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Excalidraw MCP Server environment.
Grouping elements modifies the diagram structure but does not delete data (so not Destructive), does not execute arbitrary code or external operations (so not Execute), and does not involve financial transactions (so not Financial). The operation is reversible—elements can be ungrouped. This is a classic Write operation: it creates or modifies data in a reversible manner.
From the tool's definition Tool name 'group_elements' and description 'Group multiple elements together' indicate a modification operation on diagram elements.
Documented attack patterns abuse exactly the kind of access group_elements 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 group_elements:
{
"version": "1",
"default": "deny",
"tools": {
"group_elements": {
"limits": [
{
"counter": "group_elements_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}group_elements stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Group multiple elements together. It is categorised as a Write tool in the Excalidraw MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Excalidraw MCP Server MCP server in PolicyLayer and add a rule for group_elements: 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.
group_elements is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the group_elements 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 group_elements. 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.
group_elements 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.