Medium Risk

create_list

Create a new list in a specific board

How to control create_list ↓

What create_list does on Trello MCP Server

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

Medium Risk

Why create_list needs a policy

This tool creates a new list (a reversible modification) in a Trello board. It is a Write operation because it adds data without deletion or destruction. Severity is medium because creating unwanted lists could clutter a board or disrupt workflow, but the action is easily reversible via archive_list or deletion. Confidence is high because the name and description unambiguously describe a creation action.

From the tool's definition Tool name 'create_list' and description 'Create a new list in a specific board' explicitly indicate creation of new data structure.

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

How to control create_list

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

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

create_list 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 Trello 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 →

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Related tools and policies

Go deeper

Questions about create_list

What does the create_list tool do? +

Create a new list in a specific board. It is categorised as a Write tool in the Trello 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_list? +

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

What risk level is create_list? +

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

Can I rate-limit create_list? +

Yes. Add a rate_limit block to the create_list 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_list completely? +

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

create_list is provided by the Trello MCP Server MCP server (lzvxck/trello-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Trello MCP Server tool call.

Start from Trello MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

11 Trello MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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