Trello MCP Server

list_attachments

Lists all attachments on a Trello card by providing its card ID. Use this to review or retrieve associated files.

Instructions

Liste tous les attachments d'une carte

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": "list_attachments"
  }
}

Input Schema

Name	Required	Description	Default
`cardId`	Yes	Parameter cardId (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. The verb 'list' implies a read-only operation, but the description does not mention whether any filtering or ordering applies, what the return data looks like, or any side effects. For a tool with no output schema, this leaves a notable gap.

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, direct sentence with no redundant words or filler. It is front-loaded with the action and resource, earning its place without unnecessary elaboration.

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 one-parameter list tool with no annotations and no output schema, this description is minimally viable. It tells the agent what action to perform and on what resource, but it leaves out details about the return format, attachment types, and potential error conditions, which an agent might need for confident invocation.

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 description coverage is 100%, so the baseline is 3 even though the description adds no parameter information. The schema itself only says 'Parameter cardId (24 characters)', which is weak but technically present. The tool description does not clarify the parameter's meaning beyond what the schema already provides.

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 clearly states a specific action (list) on a specific resource (attachments) scoped to a card, so an agent can understand what the tool does. However, it does not explicitly differentiate itself from sibling attachment tools like add_attachment_url or delete_attachment, though the action verb makes the distinction fairly obvious.

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?

There is no guidance on when to use this tool versus alternatives, no exclusions, and no mention of prerequisites or context. The intended use case is implied by the verb 'list' and the card scoping, but nothing is stated explicitly.

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

Deploy Server