Trello MCP Server

set_card_cover

Set or remove a card cover by attaching an image. Specify the card ID and attachment ID to update the cover on any Trello card.

Instructions

Définit ou retire le cover d'une carte (via attachment)

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>"
    },
    "name": "set_card_cover"
  }
}

Input Schema

Name	Required	Description	Default
`cardId`	Yes	Parameter cardId (24 characters)
`attachmentId`	No	Parameter attachmentId (24 characters)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.0Sep 6, 2026

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does reveal that the tool can both set and remove a cover, but it does not explain the side effects, what happens when attachmentId is omitted, or any permissions or reversibility considerations.

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, focused sentence with no filler. It conveys the essential purpose and mechanism efficiently, making it easy for an agent to parse quickly.

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 tool, the description covers the core purpose. However, with no annotations and no output schema, it lacks important detail about how the optional attachmentId affects behavior, especially the removal case, which an agent would need to infer.

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?

Schema coverage is 100%, so each parameter has at least a basic description. The tool description adds 'via attachment', which hints that attachmentId is the attachment used as the cover, but it does not clarify the conditional semantics of omitting attachmentId. Baseline 3 is appropriate given the high schema coverage.

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

Purpose5/5

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

The description states a clear action ('Définit ou retire') on a specific resource (a card's cover) and identifies the mechanism ('via attachment'). It distinguishes this tool from card attachment tools like add_attachment_url by focusing on the cover concept.

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?

The description gives no explicit guidance on when to use this tool versus alternatives, nor does it mention exclusions or prerequisites. The cover-specific purpose is implied, but there is no direction about when to choose this over related card or attachment operations.

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

Deploy Server