create_subtask · Vikunja MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_subtask does on Vikunja MCP Server

AI agents use create_subtask to create or update resources in Vikunja MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Vikunja MCP Server environment.

WHY IT NEEDS A POLICY

Why create_subtask needs a policy

This tool creates new data within Vikunja's task management system in a reversible manner. It is not destructive (subtasks can be deleted), does not execute arbitrary code, and does not move money. It qualifies as Write.

From the tool's definition Tool name 'create_subtask' and description 'Create a subtask under a parent task' indicate creation of new data. The verb 'Create' and the action of adding a subtask are reversible operations (can be deleted via sibling tool 'delete_task').

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_subtask Rate-limited

create_subtask 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.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Vikunja MCP Server, so you can run agents against it safely.

FAQ

Questions about create_subtask

What does the create_subtask tool do? +

Create a subtask under a parent task. It is categorised as a Write tool in the Vikunja MCP 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 create_subtask? +

Register the Vikunja MCP Server MCP server in PolicyLayer and add a rule for create_subtask: 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 Vikunja MCP Server. Nothing to install.

What risk level is create_subtask? +

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

Can I rate-limit create_subtask? +

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

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

create_subtask is provided by the Vikunja MCP Server MCP server (wosh-i/vikunja-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.