AI agents use auto_layout to create or update resources in MCP-BPMN Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP-BPMN Server environment.
The auto_layout tool modifies the diagram's layout properties (positioning, spacing) in a reversible manner. This is a Write operation because it transforms existing diagram metadata (visual properties) but does not create new elements, execute external code, delete components, or involve financial transactions. The modification is non-destructive and can be undone by applying a different layout.
From the tool's definition Tool applies automatic layout to the current diagram, modifying the visual structure and arrangement of the BPMN diagram without deleting or destructively altering the underlying process logic.
Documented attack patterns abuse exactly the kind of access auto_layout gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP-BPMN Server, and nothing reaches the server without passing your rules. This is the rule we recommend for auto_layout:
{
"version": "1",
"default": "deny",
"tools": {
"auto_layout": {
"limits": [
{
"counter": "auto_layout_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} auto_layout 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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Apply automatic layout to the current diagram. It is categorised as a Write tool in the MCP-BPMN Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP-BPMN Server MCP server in PolicyLayer and add a rule for auto_layout: 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 MCP-BPMN Server. Nothing to install.
auto_layout 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 auto_layout 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 auto_layout. 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.
auto_layout is provided by the MCP-BPMN Server MCP server (oisee/mcp-bpmn). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP-BPMN Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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41 MCP-BPMN Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.