Slack

• Slack Add Reaction — Add a reaction emoji to a Slack message. Use the message's ts from channel history as the timestamp. Common reactions: thumbsup, heart, fire, eyes, white_check_mark, rocket, tada. Adding the same reaction twice is idempotent (no error).
• Slack Auth Test — Verify the saved Slack token is accepted by Slack's auth.test endpoint. Use after connecting or rotating a bot, user, or app-level token.
• Slack Channel Members — List members of a Slack channel. Returns user IDs of all members. Look up workspace users by user ID for profile details. Requires the bot to be in the channel.
• Slack Channel Messages — Read messages from a Slack channel or DM. Accepts #name, @user, or channel id. Limit can be a count or time window (7d, 1w). User IDs resolve to display names from the workspace directory.
• Slack Channels — Get Slack channels and DMs. Pass channel_id as #name, @user, or raw id for one channel, or omit to list. Returns directory metadata (cache age, counts). Set refresh=true after workspace changes to rebuild the name index.
• Slack Get File — Get Slack file metadata (name, type, size, permalink). Set download=true to fetch file bytes; large files return a presigned download link instead of inline content.
• Slack Get Thread Replies — Get all replies in a Slack message thread. Accepts #channel, @user DM, or channel id. The first message in the response is the parent. Limit accepts count or time window (7d).
• Slack Join Channel — Join a public Slack channel so the bot can read and post messages. Call this when reading history or posting returns a not_in_channel error. Only works for public channels — private channels require a manual invite. If already in the channel, this is a no-op.
• Slack Post Message — Post a new message to a Slack channel. Accepts #channel, @dm-user, or channel id. Returns the posted message ts for threading.
• Slack Remove Reaction — Remove a reaction emoji from a Slack message. Use the message ts from channel history. Removing a reaction that is not present is idempotent.
• Slack Reply To Thread — Reply to a message thread in Slack. The thread_ts is the ts of the parent message — from channel history or from a recent post response.
• Slack Search Messages — Search messages across Slack. Pass natural language or a permalink as query, plus optional filters for channel, author, dates, and threads-only. Uses user search token when available; falls back to bot search.
• Slack Update Usergroup Members — Add or remove workspace members from a Slack @mention usergroup. Pass add_user_ids and/or remove_user_ids; user ids and @handles are accepted.
• Slack Upsert Usergroup — Create or update a Slack @mention usergroup. Omit usergroup_id to create; pass usergroup_id to update name, handle, description, channels, or enabled state.
• Slack Usergroups — List Slack @mention usergroups or fetch one by usergroup_id. Usergroups group members for broadcast mentions.
• Slack Users — Get Slack workspace members. Pass user_id as @handle or U… id for one profile, or omit to list. Includes directory metadata on list responses.

Schemas and invoke metadata: Directory API