cancel_task · Todos MCP: Risk & Policy

WHAT IT DOES

What cancel_task does on Todos

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

WHY IT NEEDS A POLICY

Why cancel_task needs a policy

Cancelling a task modifies its status in the system. While it changes state, task cancellation is typically reversible (tasks can be reopened or reactivated), placing it in Write rather than Destructive. The blast radius is medium since cancelling the wrong task could disrupt workflows but is generally recoverable.

From the tool's definition 'Mark a task as cancelled' — changes task state to cancelled

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cancel_task Rate-limited

cancel_task 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": {
    "cancel_task": {
      "limits": [
        {
          "counter": "cancel_task_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 Todos, so you can run agents against it safely.

FAQ

Questions about cancel_task

What does the cancel_task tool do? +

Mark a task as cancelled. It is categorised as a Write tool in the Todos MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on cancel_task? +

Register the Todos MCP server in PolicyLayer and add a rule for cancel_task: 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 Todos. Nothing to install.

What risk level is cancel_task? +

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

Can I rate-limit cancel_task? +

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

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

cancel_task is provided by the Todos MCP server (@hasna/todos). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.