createCard · Trello MCP Server MCP: Risk & Policy

WHAT IT DOES

What createCard does on Trello MCP Server

AI agents use createCard 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.

WHY IT NEEDS A POLICY

Why createCard needs a policy

This tool creates new data (a Trello card) which is a Write operation. The blast radius is low since cards can be easily deleted or archived, and the operation is entirely within Trello's data model with no side effects beyond the card creation itself. It does not execute code, delete data irreversibly, move financial resources, or trigger external system operations.

From the tool's definition Tool creates a new card in a Trello list—a reversible data creation operation. Description states 'Create a new card' with no indication of destructive or code execution capabilities.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

createCard Rate-limited

createCard 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": {
    "createCard": {
      "limits": [
        {
          "counter": "createcard_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 Trello MCP Server, so you can run agents against it safely.

FAQ

Questions about createCard

What does the createCard tool do? +

Create a new card in a Trello list. Use this to add tasks, ideas, or items to your workflow. 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 createCard? +

Register the Trello MCP Server MCP server in PolicyLayer and add a rule for createCard: 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 createCard? +

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

Can I rate-limit createCard? +

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

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

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