Add a member to a Trello card by member ID to assign ownership or participation; requires write access to the card's board and an assignable member.
Use when assigning a Trello member to a card by member id; requires write access to the card's board and a member who can be assigned to that board.
| Name | Required | Description | Default |
|---|---|---|---|
| cardId | Yes | Trello card id, short link, or Trello card URL. | |
| memberId | Yes | Trello member id to add or remove from the card. |
Changes observed during successful MCP inspections.
v1.0.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It usefully discloses authorization and eligibility requirements, but it does not mention idempotency, what happens if the member is already assigned, or expected response behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single front-loaded sentence with no wasted wording. It immediately tells the agent when to use the tool and what prerequisites apply.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
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 annotations and no output schema, the description covers the main authorization and eligibility requirements. However, it omits return behavior and edge-case handling, leaving some gaps for an agent invoking a write operation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, and both parameters are already well documented in the schema. The description reinforces that assignment is by member id and references the card's board, but adds little beyond what the schema provides.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific action (assigning a Trello member to a card) with the key resource and identifier. It is clear what the tool does, though it does not explicitly name the sibling alternative card_member_remove to disambiguate add vs. remove.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'Use when assigning a Trello member to a card' gives a clear usage condition, and the description adds prerequisites: write access to the card's board and a member eligible to be assigned. It does not explicitly state when not to use it or name alternatives, but the context is strong.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.