Trello MCP Server

add_member_to_card

Assign a specified member to a Trello card using card ID and member ID, ensuring accurate team assignment on your boards.

Instructions

Assigne un membre 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>",
      "memberId": "<memberId>"
    },
    "name": "add_member_to_card"
  }
}

Input Schema

Name	Required	Description	Default
`cardId`	Yes	Parameter cardId (24 characters)
`memberId`	Yes	Parameter memberId (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 full burden of behavioral disclosure. It only restates the core action and gives no details about side effects, whether assigning an already-assigned member is an error or no-op, permission requirements, or what response to expect. This is a meaningful gap for a mutating tool.

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, front-loaded sentence with no filler words or redundant information. It is as concise as possible while still conveying the tool's purpose.

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 with no output schema and no annotations, the description is minimally adequate: it states the operation and the schema defines the inputs. But it lacks any behavioral context such as idempotence, duplicate handling, or result format, leaving an agent without full confidence about edge cases.

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%, and both parameters are documented with their types and character-length constraints, so the schema already handles parameter understanding. The description adds no extra semantic detail about what cardId or memberId represent, so the baseline score applies.

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 clear, specific action: assigning a member to a Trello card. It is immediately understandable and distinct from label-related or list-related tools, but it does not explicitly differentiate itself from closely related siblings such as bulk_assign_member or remove_member_from_card.

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

Usage Guidelines3/5

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

The purpose implicitly tells an agent to use this tool when a single member should be assigned to a single card. However, there is no explicit guidance about when not to use it, no prerequisites, and no mention of alternatives like bulk_assign_member for batch operations.

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

Deploy Server