Trello MCP — Personal remote connector for Claude

A small, opinionated MCP server that lets Claude read and update Trello boards. Runs on Cloudflare Workers, gated behind GitHub OAuth, allowlisted to a single GitHub user.

Designed primarily around Dann Bleeker Pedersen's GTD workflow, but the underlying tools are generic — friendly aliases for boards / lists / labels live in src/trello/constants.ts and are easy to extend for other workflows.

Tools (20)

Reads

Tool	Purpose
list_boards	All open boards the authenticated Trello user belongs to
list_lists	Lists on a board (alias or ID)
list_cards	Cards on a list or board; includes desc; optional label / staleDays filters
get_card	Full details for one card
search_cards	Fuzzy name search, scoped or unscoped; includes desc
list_checklist_items	Checklists + items on a card
list_attachments	Attachments on a card (id, name, url, date, mimeType)

Writes

Tool	Purpose
create_card	New card on a list (with guards + WIP warning)
move_card	Move card between lists (guards source AND destination)
update_card	Edit name / description / due date
archive_card	Soft archive (closed=true). Hard delete is not implemented.
set_due_complete	Mark due date as done (triggers Butler automations)
set_checklist_item_state	Tick / untick a single checklist item
add_label	Apply a label by ID or name
remove_label	Remove a label by ID or name
add_comment	Append a comment to a card
add_checklist_item	Append an item to the card's checklist
add_attachment	Attach a URL to a card
add_file_attachment	Upload a real file (base64 → multipart). 10 MB hard cap — for larger files, host the file and use add_attachment with a URL.
remove_attachment	Remove an attachment from a card

Safety guards

Enforced server-side before any Trello call — same rules for every tool, no per-tool drift:

• Forbidden lists (Butler, Repeater Cards) — all writes refused. These lists hold automation rules and recurring templates; the connector observes but never modifies them.
• Read-only lists (Rolling Big Rocks) — move_card source OR destination refused. create_card to this list refused.
• WIP-limit warnings — when a move_card or create_card puts a list with a (WIP limit N) suffix over its limit, the response includes a warning, but the call still succeeds (treats WIP as guidance, not enforcement).
• No hard delete — the capability is not in the code. archive_card is the only destructive-feeling operation, and it's reversible from the Trello UI.

Access control

Only one GitHub login (dannbleeker) can call any tool — hard-coded in src/index.ts. Any other authenticated GitHub user reaches the OAuth flow but every tool call returns a refusal message.

Setup

1. GitHub OAuth app

Create an OAuth app at https://github.com/settings/developers:

• Homepage URL: https://trello-mcp.<your-subdomain>.workers.dev
• Authorization callback URL: https://trello-mcp.<your-subdomain>.workers.dev/callback
• Note the Client ID and generate a Client secret.

For local development, register a second OAuth app with:

• Homepage URL: http://localhost:8788
• Authorization callback URL: http://localhost:8788/callback

2. Trello credentials

You need an API key and a user token:

Value	Where
API key	https://trello.com/power-ups/admin → create an app → API key
Token	https://trello.com/1/authorize?key=YOUR_KEY&name=Claude&expiration=never&response_type=token&scope=read,write

3. KV namespace + secrets

# install deps
pnpm install

# create the KV namespace, then paste the returned id into wrangler.jsonc
pnpm exec wrangler kv namespace create OAUTH_KV

# production secrets
pnpm exec wrangler secret put GITHUB_CLIENT_ID
pnpm exec wrangler secret put GITHUB_CLIENT_SECRET
pnpm exec wrangler secret put COOKIE_ENCRYPTION_KEY   # openssl rand -hex 32
pnpm exec wrangler secret put TRELLO_KEY
pnpm exec wrangler secret put TRELLO_TOKEN

# deploy
pnpm exec wrangler deploy

For local dev, copy .dev.vars.example to .dev.vars and fill in the values; then pnpm dev.

4. Add to claude.ai

Settings → Connectors → Add custom connector. URL: https://trello-mcp.<your-subdomain>.workers.dev/mcp. Sign in with GitHub when prompted.

Adding a new board

1. In Trello: copy the board's 24-char ID from the URL or from a list_boards call.
2. In src/trello/constants.ts: add an entry to BOARD_ALIASES.
3. Optionally add list aliases under LIST_ALIASES.
4. Optionally mark any list as forbidden or read-only.
5. pnpm exec wrangler deploy.

No tool code changes are needed — the existing tools resolve aliases at call time.

Project layout

src/
  index.ts                  — Worker entry, OAuth wiring, tool registrations
  github-handler.ts         — OAuth consent screen + GitHub callback
  utils.ts                  — auth helpers (unchanged from template)
  workers-oauth-utils.ts    — cookie/state utilities (unchanged from template)
  trello/
    client.ts               — typed Trello REST client (retry on 429 + 5xx)
    constants.ts            — aliases, forbidden + read-only lists, WIP parser
    guards.ts               — server-side safety guards
    tools.ts                — 20 tool implementations (testable in plain Node)
wrangler.jsonc              — Cloudflare Workers config
package.json
tsconfig.json
.dev.vars.example

Development

pnpm install
pnpm type-check         # tsc --noEmit
pnpm dev                # wrangler dev → http://localhost:8788

Related

• dannbleeker/trello-plugin — the local Python MCP for Claude Code on the same Trello account. The two coexist; this one is the remote connector for claude.ai.

License

MIT.