trello_attach_link · Mtl Trello MCP: Risk & Policy

WHAT IT DOES

What trello_attach_link does on Mtl Trello

AI agents use trello_attach_link 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_attach_link needs a policy

Attaching a link to a card is a write operation that adds metadata to a card without deleting, overwriting irreversibly, executing code, or moving funds. The action is reversible (the attachment can be removed). Severity is low because attaching a link has minimal blast radius — it adds non-destructive metadata and cannot compromise data integrity or trigger unintended side effects.

From the tool's definition Tool description states 'Attach a URL (web link) to a Trello card' — this creates a new attachment resource on an existing card, modifying card data reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

trello_attach_link Rate-limited

trello_attach_link 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_attach_link": {
      "limits": [
        {
          "counter": "trello_attach_link_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_attach_link

What does the trello_attach_link tool do? +

Attach a URL (web link) 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_attach_link? +

Register the Mtl Trello MCP server in PolicyLayer and add a rule for trello_attach_link: 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_attach_link? +

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

Can I rate-limit trello_attach_link? +

Yes. Add a rate_limit block to the trello_attach_link 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_attach_link completely? +

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

trello_attach_link 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.