add_comment

Add a comment to a card.

SERVERTrello SOURCEartemnikov/trello-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade B, identity unverified Pull the record →

This record as markdown: /tools/artemnikov-trello-mcp/add-comment.md

WHAT IT DOES

What add_comment does on Trello

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

RISK

Why add_comment is rated Medium

Adding a comment modifies a card by appending a comment, which is a standard Write operation. It is not destructive (comments can be edited or deleted), not financial, not executable code, and not a simple read. The blast radius is minimal since comments are non-critical metadata and easily reversible. Severity is low because misuse would only create unwanted comments, causing minor disruption.

From the tool's definition Tool name is 'add_comment' and description states 'Add a comment to a card.' This creates new data (a comment) on a Trello card, which is a reversible write operation.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs add_comment safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Trello, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For add_comment, this is the rule to start with:

add_comment Rate-limited

add_comment 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": {
    "add_comment": {
      "limits": [
        {
          "counter": "add_comment_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Trello, apply this rule, and every add_comment call is checked against it from then on.

FAQ

Questions about add_comment

What does the add_comment tool do? +

Add a comment to a card. It is categorised as a Write tool in the 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 add_comment? +

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

What risk level is add_comment? +

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

Can I rate-limit add_comment? +

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

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

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

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