Trello MCP Server

> 🔀 Active fork. This is a maintained fork of kocakli/Trello-Desktop-MCP integrating contributions from across the fork ecosystem (kevinhillinger, zonca, dbz-max, maks244, jantman, ThatIanMcShane, josh-argyle). PRs welcome — see Credits for what each contributor brought in. Published on npm as `atlassian-trello-mcp`.

A Model Context Protocol (MCP) server for Trello that works with any MCP-compatible client -- Claude Desktop, Claude Code, Gemini CLI, and more.

Provides 50 tools covering boards, cards, lists, labels, checklists, attachments, members, custom fields, and search.

Quick Start

1. Get Trello API credentials

Trello no longer hands out API keys directly — each user must create their own Power-Up, then mint a token against that Power-Up's key.

1. Visit https://trello.com/power-ups/admin and click New.

2. Fill out the New Power-Up or Integration form:

3. Once the Power-Up is created, click API key in the sidebar, then Generate a new API key, then Generate API key in the confirmation modal. Trello displays both an API key and a Secret — save them somewhere safe.

4. In a browser, visit:

https://trello.com/1/authorize?expiration=never&scope=read,write,account&response_type=token&name={NAME}&key={APIKEY}

Replace `{NAME}` with the Power-Up name you chose and `{APIKEY}` with the key from the previous step. This is an auth prompt — confirm access and click Allow. Trello returns an API token; copy it.

5. Put the API key and token into your MCP client config (e.g. `.claude.json`) — see the next section.

2. Install

The easiest path is `npx` — no clone, no build, just run:

npx atlassian-trello-mcp

Or install from source:

git clone https://github.com/agrath/Trello-Desktop-MCP.git
cd Trello-Desktop-MCP
npm install
npm run build

3. Configure your MCP client

Claude Desktop

Edit your config file:

• macOS: `~/Library/Application Support/Claude/claude_desktop_config.json`
• Windows: `%APPDATA%\Claude\claude_desktop_config.json`
• Linux: `~/.config/Claude/claude_desktop_config.json`

{
  "mcpServers": {
    "trello": {
      "command": "npx",
      "args": ["-y", "atlassian-trello-mcp"],
      "env": {
        "TRELLO_API_KEY": "your-api-key",
        "TRELLO_TOKEN": "your-token"
      }
    }
  }
}

Claude Code

claude mcp add trello -- npx -y atlassian-trello-mcp

Set environment variables `TRELLO_API_KEY` and `TRELLO_TOKEN`, or pass credentials per-request.

Gemini CLI

Edit `~/.gemini/settings.json`:

{
  "mcpServers": {
    "trello": {
      "command": "npx",
      "args": ["-y", "atlassian-trello-mcp"],
      "env": {
        "TRELLO_API_KEY": "your-api-key",
        "TRELLO_TOKEN": "your-token"
      }
    }
  }
}

Generic MCP client / source install

The server uses stdio transport. Run with environment variables set:

TRELLO_API_KEY=your-key TRELLO_TOKEN=your-token npx atlassian-trello-mcp
# or, from a source clone:
TRELLO_API_KEY=your-key TRELLO_TOKEN=your-token node dist/index.js

Credentials

Credentials can be provided two ways:

1. Environment variables (recommended): Set `TRELLO_API_KEY` and `TRELLO_TOKEN`

2. Per-request: Pass `apiKey` and `token` as tool parameters (overrides env vars)

Available Tools (50)

Boards & Lists

Cards

Comments & Activity

Labels

Members on Cards

Attachments

Checklists

Check Items

Search

Configuration

Read-only mode

Set `TRELLO_READ_ONLY=true` to disable all write operations. The 25 write tools are hidden from `tools/list` and rejected if called anyway, leaving the 25 read tools available.

The policy is an allowlist of read tools, so it fails closed: any tool added later is treated as a write until it is explicitly classified as a read.

{
  "env": {
    "TRELLO_API_KEY": "your-key",
    "TRELLO_TOKEN": "your-token",
    "TRELLO_READ_ONLY": "true"
  }
}

Compact mode

Several tools support a `compact` parameter (default: `true`) that returns minimal fields to reduce response size. Set `compact: false` for full details including descriptions, labels, members, and custom fields.

Tools with compact mode: `get_board_details`, `trello_get_board_cards`, `trello_get_list_cards`, `trello_search`.

Image attachment download

When `get_card` is called and the card has image attachments, the server downloads them and returns them as inline MCP image content blocks alongside the JSON — letting the client see card images directly. Downloads are restricted to Trello-hosted URLs (`*.trello.com`, `trello-attachments.s3.amazonaws.com`) and capped at 5 MB per image to mitigate SSRF and payload-bloat risks.

Set `TRELLO_DOWNLOAD_IMAGES=false` (or `0`/`no`/`off`) to disable entirely — the server will skip the extra `getCardAttachments` call and return text only. Default is enabled.

Logging

Set `TRELLO_MCP_LOGGING=true` to enable file-based logging via Pino. Logs are written to `dist/logs/app.log`.

Development

Project structure

src/
  index.ts              Entry point (credential injection, tool routing, read-only enforcement)
  tools/
    boards.ts           Board tools (list, details, lists, filter)
    cards.ts            Card tools (CRUD, archive)
    lists.ts            List tools (cards, create list, comments)
    members.ts          Member tools (user boards, member details)
    search.ts           Search tool
    advanced.ts         Labels, attachments, members on cards, custom fields
    checklists.ts       Checklist and check item tools (13 tools)
  trello/
    client.ts           TrelloClient (API calls, retry, rate limiting)
  types/
    trello.ts           TypeScript interfaces
  utils/
    validation.ts       Zod schemas, extractCredentials, extractTrelloId
    logger.ts           Pino file logger
    readOnly.ts         Read-only mode policy (read-tool allowlist)
    health.ts           Health check utility
    appInsights.ts      Telemetry (no-op)
tests/
  validation.test.ts    Validation and credential extraction tests
  trelloClient.test.ts  API client tests (mocked fetch)
  tools.test.ts         Tool handler tests (mocked client)
  readOnly.test.ts      Read-only mode policy tests

Build & test

npm install
npm run build
npm test
npm run type-check

Key patterns

• ID resolution: All tools accept Trello URLs, short IDs, or full 24-char hex IDs via `extractTrelloId()`
• Credential fallback: `extractCredentials()` checks args first, then env vars
• Retry with backoff: TrelloClient retries on 500/network errors (3 attempts, exponential backoff)
• Rate limiting: Extracts and returns `x-rate-limit-*` headers from every response
• Validation: Zod schemas validate all inputs before API calls

Contributing

Pull requests are welcome and actively reviewed. This fork is maintained by an extensive Trello user, so features get real-world testing.

If you've forked the original project and built something useful, please submit a PR here rather than maintaining a separate fork -- it's easier for everyone to benefit from a single well-maintained project.

To contribute:

1. Fork this repo

2. Create a feature branch

3. Add tests for new functionality

4. Run `npm test` and `npm run build`

5. Submit a pull request with a clear description of what and why

Credits

This project is a fork of kocakli/Trello-Desktop-MCP. Features and ideas were incorporated from across the fork ecosystem:

• **kocakli** -- Original project, MCP client-agnostic rebranding, stderr logging fix
• **kevinhillinger** -- Credential injection architecture, label deletion, card member management, card archiving, expanded TypeScript types, resources layer
• **zonca** -- Centralized credential handling with env var fallback, label management tools, comprehensive unit tests, improved TypeScript types replacing `any`
• **dbz-max** -- Custom fields support (board custom fields + card custom field items)
• **maks244** -- Read-only mode concept, list filtering by name, credential stripping from telemetry logs
• **jantman** -- Fix for numeric `pos` values rejected when sent as strings by MCP clients
• **ThatIanMcShane** -- Bumped `@modelcontextprotocol/sdk` 1.0.4 → 1.29.0 to fix connection timeouts with current Claude Code releases
• **josh-argyle** -- Auto-download image attachments in `get_card` responses as inline MCP image content blocks (with allowlist + size cap added during port)
• **l-double-l** -- `trello_update_list`, `trello_get_board_actions` with since/before paging, and the member ID injection fix (widened during port to validate every ID field)
• **Gileba** -- Independent `trello_update_list` implementation, which informed the ported tool's shape
• **TheCodeSharman** -- `idShort` (the board-local `#N` card number) surfaced across all card projections, and `trello_get_card_by_number` to resolve a quoted card number to a card

License

MIT