list_diagrams

THE RISK

Low Risk

Why list_diagrams needs a policy

This tool queries and retrieves a list of existing BPMN diagrams without modifying, creating, deleting, or executing anything. It is a straightforward read operation with minimal blast radius if misused by an AI agent.

From the tool's definition Tool name is 'list_diagrams' and description states it 'List all saved BPMN diagrams' — a retrieval operation with no side effects.

Documented attack patterns abuse exactly the kind of access list_diagrams gives an agent:

POLICY

How to control list_diagrams

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 list_diagrams:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_diagrams": {}
  }
}

list_diagrams is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP-BPMN Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP-BPMN Server tools

Destructive bpmn_delete_diagram Delete a saved BPMN diagram file Destructive bpmn_delete_element Delete an element from the process Destructive delete_diagram_file Delete a saved BPMN diagram file Destructive delete_element Delete an element from the current diagram Write new_bpmn Create a new BPMN diagram and set it as current context Write new_from_mermaid Create a new BPMN diagram from Mermaid code and set it as current context Write add_activity Add an activity to the current diagram Write add_event Add an event to the current diagram

All 41 MCP-BPMN Server tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about list_diagrams

What does the list_diagrams tool do? +

List all saved BPMN diagrams. It is categorised as a Read tool in the MCP-BPMN Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_diagrams? +

Register the MCP-BPMN Server MCP server in PolicyLayer and add a rule for list_diagrams: 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.

What risk level is list_diagrams? +

list_diagrams is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_diagrams? +

Yes. Add a rate_limit block to the list_diagrams 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.

How do I block list_diagrams completely? +

Set action: deny in the PolicyLayer policy for list_diagrams. 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.

What MCP server provides list_diagrams? +

list_diagrams 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.

Enforce policy on every MCP-BPMN Server tool call.

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.

CHECK YOUR STACK →