Trello MCP Server

add_label_to_card

Attach a label to a Trello card by supplying the card ID and label ID, enabling organized task categorization and clearer board visibility.

Instructions

Ajoute un label à une carte Trello

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "cardId": "<cardId>",
      "labelId": "<labelId>"
    },
    "name": "add_label_to_card"
  }
}

Input Schema

Name	Required	Description	Default
`cardId`	Yes	Parameter cardId (24 characters)
`labelId`	Yes	Parameter labelId (24 characters)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.0Sep 6, 2026

TDQS

B3.1/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of behavioral disclosure, but it only states the basic action. It does not mention idempotency, duplicate label handling, required label existence, permissions, or failure behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise, front-loaded sentence with no wasted words. It conveys the core purpose efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-parameter mutation, the description covers the essential action and parameters. However, the lack of output schema and absence of behavioral details or usage guidance leave some gaps for an agent deciding between this and related bulk/removal tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already documents both parameters, so the description adds minimal semantic value. The parameter names 'cardId' and 'labelId' are self-explanatory in context, but the description does not clarify expected formats beyond the schema's brief '24 characters' notes.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('ajoute') and resource ('un label à une carte Trello'), clearly conveying the action. It is distinguishable from siblings like remove_label_from_card, though it does not explicitly contrast with bulk_add_label.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives such as bulk_add_label or remove_label_from_card. The description only states what the tool does, leaving the agent to infer usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server