Medium Risk

update_todo

update_todo

How to control update_todo ↓

AI agents use update_todo to create or update resources in Things 3 MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Things 3 MCP Server environment.

Medium Risk

The 'update_todo' tool modifies task records in Things 3, which is a Write operation (reversible change to existing data). It does not delete (Destructive), execute arbitrary code (Execute), or involve money (Financial). Severity is medium because misuse could modify many tasks, but changes are reversible and limited to task metadata/state without affecting system integrity.

From the tool's definition Tool name 'update_todo' indicates modification of existing task data. Sibling tools include 'add_todo' and 'add_project', establishing this server's purpose as task management with create/modify capabilities.

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

PolicyLayer is an MCP gateway — it sits between your AI agents and Things 3 MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_todo:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_todo": {
      "limits": [
        {
          "counter": "update_todo_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

update_todo 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.

  1. Create a free account and register Things 3 MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

Free to start. No card required.

Go deeper

What does the update_todo tool do? +

update_todo. It is categorised as a Write tool in the Things 3 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 update_todo? +

Register the Things 3 MCP Server MCP server in PolicyLayer and add a rule for update_todo: 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 Things 3 MCP Server. Nothing to install.

What risk level is update_todo? +

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

Can I rate-limit update_todo? +

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

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

update_todo is provided by the Things 3 MCP Server MCP server (rossshannon/things3-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Things 3 MCP Server tool call.

Deterministic rules across all 24 Things 3 MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

24 Things 3 MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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