trello_assign_card · Mtl Trello MCP: Risk & Policy

WHAT IT DOES

What trello_assign_card does on Mtl Trello

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

WHY IT NEEDS A POLICY

Why trello_assign_card needs a policy

This tool creates or modifies data (card membership assignments) without permanently deleting data or executing arbitrary code. Assignments can be undone by removing members, making it a Write operation rather than Destructive. The severity is medium because misconfiguration could assign unintended members to sensitive tasks, but the impact is limited to Trello metadata and reversible.

From the tool's definition "Assign members to a Trello card" — modifies card state by adding member assignments, which is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

trello_assign_card Rate-limited

trello_assign_card 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": {
    "trello_assign_card": {
      "limits": [
        {
          "counter": "trello_assign_card_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 Mtl Trello, so you can run agents against it safely.

FAQ

Questions about trello_assign_card

What does the trello_assign_card tool do? +

Assign members to a Trello card. It is categorised as a Write tool in the Mtl Trello MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on trello_assign_card? +

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

What risk level is trello_assign_card? +

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

Can I rate-limit trello_assign_card? +

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

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

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