open_bpmn

THE RISK

Low Risk

Why open_bpmn needs a policy

The tool reads an existing BPMN file from disk and loads it into the current working context. This is a read/load operation with no data modification or deletion. The slight risk is that setting a new 'current context' may affect subsequent operations, but the tool itself does not alter any data. Severity is low as misuse would only result in loading an unintended file.

From the tool's definition Open an existing BPMN file and set it as current context

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

POLICY

How to control open_bpmn

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 open_bpmn:

policy.json

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

open_bpmn 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 open_bpmn

What does the open_bpmn tool do? +

Open an existing BPMN file and set it as current context. 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 open_bpmn? +

Register the MCP-BPMN Server MCP server in PolicyLayer and add a rule for open_bpmn: 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 open_bpmn? +

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

Can I rate-limit open_bpmn? +

Yes. Add a rate_limit block to the open_bpmn 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 open_bpmn completely? +

Set action: deny in the PolicyLayer policy for open_bpmn. 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 open_bpmn? +

open_bpmn 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 →