Trello MCP Server — Usage Skill

Trello MCP tools are action-dispatched (action: "..." selects the operation) and validate strictly: a field not used by the chosen action is rejected, not ignored.

1. Identify the current user first

Call trelloReadMember with action: "get_me" to get the authenticated user's profile, including prefs.timezone. Do this before any relative-time request ("today", "this week") for cards, Inbox, and search — most concretely, before trelloWriteCard/trelloWriteInbox create or update when the user gives a due date/time in local or relative terms (e.g. "tomorrow 1pm"): resolve prefs.timezone first, convert to UTC, then pass that as due. (Planner events use a different timezone source — see §3.)

2. ARI id format (critical — read before passing any id)

Every id-typed parameter (cardId, boardId, listId, workspaceId, checklistId, itemId, labelId, plannerCalendarId, providerAccountId) is an ARI, not a raw Trello object id. Most are workspace-scoped and follow this shape:

ari:cloud:trello::<entity>/workspace/<workspaceObjectId>/<entityObjectId>

The exceptions (last four rows below) are not workspace-scoped: action, member, and planner calendar have no workspace segment, and a third-party account is a different ARI namespace.

Rules:

• Always get the ARI from a read tool first, never construct or guess one. trelloWriteCard, trelloWriteChecklist, trelloWriteInbox, and trelloWritePlanner all reject Trello URLs/short links on their id params ("Do NOT pass a Trello URL or short link; use trelloReadCard/trelloReadInbox first to obtain the ARI").
• Two read get actions also accept a plain Trello URL, as a convenience: trelloReadBoard (get) takes a board URL (https://trello.com/b/<shortLink>/...) and trelloReadCard (get) takes a card URL (.../c/<shortLink>/...), in addition to an ARI. Every other tool — and all write tools — take ARIs only.

3. Dates are always UTC ISO 8601

due (trelloWriteCard, trelloWriteInbox) and start/end (trelloWritePlanner) are UTC ISO 8601 ("2026-06-01T17:00:00.000Z"). For local/relative times, convert using:

• Cards & Inbox: trelloReadMember (get_me) → prefs.timezone
• Planner events: trelloReadPlanner (get) → primaryCalendar.timezone
• No time given → default to 09:00 local.

trelloSearch due-date qualifiers (due:) use the same UTC-boundary rule — resolve prefs.timezone first.

4. Inbox is not a Trello board

Inbox is a personal quick-capture surface with its own tools: trelloReadInbox / trelloWriteInbox. Don't try to access it via trelloReadBoard/trelloWriteBoard — go through the Inbox-specific tools instead. trelloWriteInbox create takes no pos — new Inbox cards always land at the top.

5. Ordered creation

When creating multiple items that must keep a specific order — lists, cards, checklists on a card, or check items in a checklist — set pos to distinct sequential integers (1, 2, 3, …) in the intended order. Scope is per parent: cards per list, lists board-wide, checklists per card, check items per checklist. Distinct values fix the order regardless of which call lands first, so you can create them in parallel. pos also accepts "top"/"bottom" where the field is exposed.

Example — 3 lists on a new board, order matters (To Do → In Progress → Done):

[
  {
    "tool": "trelloWriteList",
    "action": "create",
    "boardId": "ari:cloud:trello::board/workspace/<workspaceObjectId>/<boardObjectId>",
    "name": "To Do",
    "pos": 1
  },
  {
    "tool": "trelloWriteList",
    "action": "create",
    "boardId": "ari:cloud:trello::board/workspace/<workspaceObjectId>/<boardObjectId>",
    "name": "In Progress",
    "pos": 2
  },
  {
    "tool": "trelloWriteList",
    "action": "create",
    "boardId": "ari:cloud:trello::board/workspace/<workspaceObjectId>/<boardObjectId>",
    "name": "Done",
    "pos": 3
  }
]

All three can be issued in parallel — pos is per board, and distinct values (1/2/3) fix the order no matter which call lands first.

Example — 3 cards in one list, order matters (Step 1 → Step 2 → Step 3):

[
  {
    "tool": "trelloWriteCard",
    "action": "create",
    "listId": "ari:cloud:trello::list/workspace/<workspaceObjectId>/<listObjectId>",
    "name": "Step 1",
    "pos": 1
  },
  {
    "tool": "trelloWriteCard",
    "action": "create",
    "listId": "ari:cloud:trello::list/workspace/<workspaceObjectId>/<listObjectId>",
    "name": "Step 2",
    "pos": 2
  },
  {
    "tool": "trelloWriteCard",
    "action": "create",
    "listId": "ari:cloud:trello::list/workspace/<workspaceObjectId>/<listObjectId>",
    "name": "Step 3",
    "pos": 3
  }
]

pos here is scoped to that one list — a card created with pos: 1 in a different list is independent of this list's pos: 1.

Counter-example — order doesn't matter: just create the item without a pos (or with "bottom"). Don't invent sequential numbers when the user hasn't asked for a specific order — that's unrequested precision.

6. Pagination

Read tools that list collections use cursor pagination (cursor in, pageInfo.endCursor/nextCursor + hasNextPage/hasMore out). Keep paginating while hasNextPage/hasMore is true instead of assuming the first page is complete — this matters especially for trelloReadBoard list/list_by_workspace when filtering by visibility (filtered server-side per page, not globally before pagination).

7. Embedded fields are previews

Fields that nest child objects — lists on a board, labels/comments on a card, cards on a list — are capped previews, in get and list_* responses alike. <field>HasMore: true marks one as truncated: listsHasMore, labelsHasMore, checklistsHasMore, commentsHasMore.

A count, "all X", filtering, or "is that everything?" needs every child. Fetch them with the matching action, paginate until a response reports no next page (§6), and answer from those pages.

Example — "how many lists does this board have?" trelloReadBoard get returns lists with listsHasMore: true. Take the board ARI from that response to the list action, follow the cursor to the last page, then count what you collected:

{
  "tool": "trelloReadList",
  "action": "list_by_board",
  "boardId": "ari:cloud:trello::board/workspace/<workspaceObjectId>/<boardObjectId>",
  "cursor": "<endCursor/nextCursor from the previous page>"
}