add_activity

THE RISK

Medium Risk

Why add_activity needs a policy

This tool creates new BPMN diagram elements (activities/tasks) which are reversible modifications to the diagram structure. It does not execute external code, delete data irreversibly, or move money. The severity is medium because misuse could bloat or corrupt a diagram, but changes can be undone through the Write operations available on this server (implied by the presence of other add/manipulate tools).

From the tool's definition Tool name is 'add_activity' and description states 'Add an activity to the current diagram'. The verb 'add' indicates creation of new diagram elements.

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

POLICY

How to control add_activity

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 add_activity:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_activity": {
      "limits": [
        {
          "counter": "add_activity_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

add_activity 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.

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.

LIMIT 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_event Add an event to the current diagram Write add_gateway Add a gateway to the current diagram

All 41 MCP-BPMN Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about add_activity

What does the add_activity tool do? +

Add an activity 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.

How do I enforce a policy on add_activity? +

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

add_activity is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit add_activity? +

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

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

add_activity 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 →