Clickup API

clickup-api

ClickUp v3 quirks the team has been bitten by. Read before sending any message, creating any channel, or calling any ClickUp endpoint.

Hard rules (NEVER violate)

Never create public channels

Forbidden: POST /chat/channels — creates a public channel visible to the entire 50+ person workspace. This has caused real noise/cleanup incidents.

Required pattern: POST /chat/channels/direct_message with user_ids — creates a private DM (1 user) or group DM (2+ users). All messaging to teammates routes through DMs, never new public channels.

Always prefix team-facing messages with 🧞

Any ClickUp message sent to teammates via Claude — DM, group DM, thread reply, or channel post — MUST start with the 🧞 emoji. Lets recipients identify Claude-authored messages at a glance. Applies to all scripts, MCP tools, and direct API calls. No exceptions.

Endpoint reference

DM creation

• POST /chat/channels/direct_message body: {"user_ids": [<numeric>, ...]}
• 1 user_id → private 1:1 DM
• 2+ user_ids → group DM
• Returns channel ID — then POST /chat/channels/{id}/messages to send.

Thread replies

• Reply to a message: POST /messages/{message_id}/replies
• NOT the channel endpoint. A common mistake is posting back to the channel as a new top-level message instead of as a reply on the thread.

Channel listing

• GET /chat/channels — paginated. Use the cursor from next_cursor field for the next page. total_count field returns the page size, not the full count — pages have has_more.

DM creation fallback (auth-scoped failure recovery)

If POST /chat/channels/direct_message returns 401/403 (the configured token may lack v3 chat-write scope), DO NOT block. Instead:

1. List channels via clickup_get_chat_channels.
2. Filter to type=DM.
3. Probe each candidate's first few messages via clickup_get_chat_channel_messages, looking for the target user_id as sender.
4. Reuse the existing DM channel.

Reference incident: an existing teammate DM was identified this way on 2026-05-21 after v3 token auth failed.

Roster hygiene

The team_roster.json file contains stale entries for people who have left the company. Before tagging, mentioning, or sending outbound messages:

1. Cross-check against current ClickUp workspace members (clickup_get_workspace_members or clickup_resolve_assignees).
2. Filter out likely-departed members before any outbound action.
3. Departures happen in waves (15+ in one day on recent offboarding) — assume roster is stale unless freshly synced.

Partner channels — skip the noise

Do NOT assume a channel owner needs to reply to partner-channel messages unless they are directly tagged. Partner-channel messages should usually be handled by the CSM/support team. Filter untargeted partner-channel pings out of any triage workflow.

Reference

Full endpoint details in ~/.claude/reference/clickup-api.md.