List members assigned to a Trello card, using fields to limit returned member data.
Use when listing members assigned to a card; requires token access to the card's board. Use fields to keep member output small.
| Name | Required | Description | Default |
|---|---|---|---|
| cardId | Yes | Trello card id, short link, or Trello card URL. | |
| fields | No | Comma-separated Trello member fields to request; use all for detailed follow-up reads. | username,fullName,initials,avatarUrl |
Changes observed during successful MCP inspections.
v1.0.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden. It usefully discloses an auth prerequisite ('requires token access to the card's board') and a payload-reduction tactic via fields, but says nothing about pagination, ordering, or what happens when a card has no members.
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?
Two compact clauses, front-loaded with the usage condition and followed by the auth caveat. No padding or restated field names; only minor gain would come from folding the fields tip into a single tighter sentence.
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 two-parameter read tool with complete schema coverage and no output schema, the description covers trigger, auth requirement, and output-sizing advice. The only real omission is enumeration/ordering behavior of the returned member list.
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 coverage is 100%, so both cardId and fields are already documented in the schema, including accepted formats and the 'all' value. The description's 'use fields to keep member output small' merely reinforces the schema's guidance with a rationale, adding marginal value over the baseline.
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?
States a specific verb and resource ('listing members assigned to a card'), which clearly scopes it apart from board_members, workspace_members, member_cards, and search_members without needing to name them. It stops short of explicitly naming the closest sibling alternatives.
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?
'Use when listing members assigned to a card' gives a clear triggering condition, and the fields hint implies a lightweight-read use case. It never states when NOT to use it (e.g., prefer board_members for board-wide membership), so exclusions are left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.