add_label

Attach an existing label 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-label.md

WHAT IT DOES

What add_label does on Trello

AI agents use add_label 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_label is rated Medium

Adding a label to a card is a write operation that modifies card state reversibly. It does not delete, execute external code, move money, or read-only access data. The blast radius is medium because label changes could affect card organization and visibility across a Trello board, potentially causing confusion if applied incorrectly at scale, but the operation is easily reversible.

From the tool's definition Tool name is 'add_label' and description states 'Attach an existing label to a card.' This modifies card metadata by adding a label, which is a reversible operation.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs add_label 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_label, this is the rule to start with:

add_label Rate-limited

add_label 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_label": {
      "limits": [
        {
          "counter": "add_label_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_label call is checked against it from then on.

FAQ

Questions about add_label

What does the add_label tool do? +

Attach an existing label 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_label? +

Register the Trello MCP server in PolicyLayer and add a rule for add_label: 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_label? +

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

Can I rate-limit add_label? +

Yes. Add a rate_limit block to the add_label 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_label completely? +

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

add_label 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.

KEEP EXPLORING

More on Trello, and thousands of servers like it.

This server

All 16 Trello tools →

Across the catalogue

add-tag on Kanban MCP Server →kb_add on Persistent Kb →create-label on Meme MCP Server →add_video on Mcptube Vision → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →