Trello MCP Server

Add Member to Card

add_member_to_card

Assign a member to a Trello card using card and member IDs. Improve task ownership and collaboration by adding team members to cards directly.

Instructions

Assign a member to a card.

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	The ID of the card
`memberId`	Yes	The ID of the member to assign

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.0Sep 6, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations provided, the description carries the burden of behavioral disclosure. It indicates the operation is an assignment, but it does not mention side effects, idempotency, what happens if the member is already assigned, required permissions, or any impact on card membership state.

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

Conciseness4/5

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

The description is a single, clear sentence with no filler. It is appropriately brief for a simple two-parameter operation, though the wording largely repeats the tool name and title rather than adding substantial new information.

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 low-complexity tool with two fully documented parameters, the description is minimally adequate for invoking the tool. However, it lacks usage guidance, behavioral detail, and any indication of return value, which leaves the agent with a plausible but incomplete understanding of the operation.

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 input schema fully documents both 'cardId' and 'memberId'. The description adds no additional semantic detail beyond what the schema already provides, so the baseline score of 3 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 specific verb and resource: 'Assign a member to a card.' It clearly conveys the core action and aligns with the tool name, making the purpose immediately understandable. It does not explicitly distinguish itself from sibling tools like 'add_board_member' or 'remove_member_from_card', but the member-to-card resource relationship is evident.

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 provides no guidance on when to use this tool versus alternatives such as 'remove_member_from_card' or 'add_board_member'. It simply restates the action without situational context, preconditions, or exclusions.

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

Deploy Server