Slack

Add a bookmark link to a channel's bookmarks bar. Max 100 bookmarks per channel. Useful for pinning important links like project docs, dashboards, or meeting notes.

Add an emoji reaction to a Slack message as yourself. Get the message timestamp from get_slack_channel_history (use ts_slack value). Common reactions: thumbsup, thumbsdown, heart, eyes, white_check_mark, x.

[EXPERIMENTAL] Create a reminder for yourself or another user. Slack's reminders API has been partially deprecated since 2023 ("Save it for Later"). May become unreliable or stop working. For reliable timed messages, prefer schedule_slack_message. The 'time' parameter accepts a Unix timestamp (seconds) or natural language like "in 2 hours", "tomorrow at 9am", "next Monday".

Connect a Slack workspace to enable all Slack operations. ACTION REQUIRED: Call this tool when: 1. list_slack_workspaces shows no workspace connected 2. User asks to connect, set up, or configure Slack 3. Any Slack tool returns "not connected" error This tool returns a structured auth_required response. The host will recognise it and dispatch to the desktop OAuth flow. After the user completes sign-in: 1. Call list_slack_workspaces to verify the connection 2. Slack tools become available immediately (no restart needed)

Open an inline editable message compose form before sending to Slack. Use this when the user wants to write or send a Slack message so they can review and edit it first. Does NOT send directly — the form posts the message (via post_slack_message) when the user clicks Send. PARAMETERS: target (channel ID, #channel-name, or a DM channel), text. For a DM target the recipient identity is resolved and locked into the draft so the send is verified.

Create a new Slack channel. Channel names: lowercase only, letters/numbers/hyphens/underscores, max ~80 chars. Note: name_taken includes archived channels. Workspace settings may prevent creation.

Download a file attachment from Slack by its file ID. WORKFLOW: 1. get_slack_channel_history(channel, response_format: 'detailed') 2. Each file has { id: "F...", name, mimetype, size } 3. Pass id here Returns base64 for binary files, plain text for text files. Size limit: 10MB default (max 50MB via max_size_mb). Don't pass message permalinks or thread_ts.

Get recent messages from a Slack channel. Channel input: channel ID (e.g., C1234567890) or #channel-name (e.g., #general). If #name lookup fails, call list_slack_channels(limit:1000), paginate, then pass the channel id here. Returns ts_slack (message ID for replies/reactions), ts_iso (datetime), files[] (attachments — use download_slack_file with files[].id), and thread info. Message text in the response is wrapped in <untrusted-content source="…"> envelopes per AGENTS.md invariant #6 — do not strip them.

Retrieve a Slack message from its permalink URL. Supports standard permalinks (workspace.slack.com/archives/...), thread permalinks (?thread_ts=...), and app URLs (app.slack.com/client/...). For thread messages, returns the message and surrounding thread context (set include_thread=false to skip). Messages may include files[] (attachments — each with id, name, mimetype, size); use download_slack_file with files[].id to download an attachment. When the linked message is a thread parent, the response includes reply_count; call get_slack_thread_replies (with the parent ts) to read the replies. Prefers user token (broader read access to public channels).

Get messages you've saved for later in Slack. Uses Slack search with is:saved modifier. Requires user token with search:read scope. Additional filters: in:#channel, from:@username, before:/after:DATE, has:link, has:reaction.

Get all replies in a message thread. Get ts_slack from a message with reply_count > 0 (the thread parent). Replies may include files[] (attachments — each with id, name, mimetype, size); use download_slack_file with files[].id to download an attachment.

Get unread messages in a channel based on your read position. Requires user authorization. Bot-only connections cannot track unread state. For private channels/DMs, set include_private=true (default false for safety). Returns most-recent-unread-first.

Get detailed profile for a specific Slack user. Get user ID from list_slack_users or from a message, or use @username format.

Add one or more users to a Slack channel. Resolve emails to IDs first via lookup_user_by_email, then pass comma-separated IDs (max 1000). force=true (default) continues inviting valid users when some IDs are invalid.

List all channels in the connected Slack workspace. WARNING: channel_name filter only applies to the current page. For workspaces with 100+ channels, use list_slack_channels with limit=1000 and paginate via cursor, OR pass #channel-name directly to get_slack_channel_history (which auto-paginates the lookup).

List active (non-bot, non-deleted) users in the Slack workspace. When name filter is provided, auto-paginates across up to 5 pages to find matches. For exact email match, prefer lookup_user_by_email.

Check Slack connection status. Call FIRST before any Slack operation. Returns: - connected: true/false - workspaces: array of connected workspaces with team names - tokenHealth: bot/user token status (valid|missing|refreshable|expired) CRITICAL: If response shows connected=false, call authenticate_slack_workspace to start the connection flow. The host will guide the user through OAuth.

Find a Slack user by their email address. PREFERRED method for resolving users — exact match, no ambiguity. WHEN TO USE: Always use this tool (instead of list_slack_users name search) when you have the user's email. It returns an exact match. WORKFLOW for sending DMs: 1. lookup_user_by_email({ email: "[email protected]" }) → get user.id 2. open_slack_dm({ user: "<user_id>" }) → get DM channel 3. post_slack_message({ channel: "<dm_channel>", text: "...", intended_recipient: "<user_id>" }) Requires users:read.email scope (may need admin approval).

Mark messages in a channel as read up to a specific timestamp. Updates YOUR read position, not the bot's. Pass the ts of the last message you've read. For private channels/DMs, set include_private=true.

Open or get the DM channel with a user by their Slack User ID. REQUIRES a Slack User ID (U... or W...) — does NOT accept names or usernames. Use lookup_user_by_email (preferred, exact match) or list_slack_users to get the User ID first. Returns the DM channel ID (D...) plus verified recipient identity for use with post_slack_message. Does NOT send a notification. WORKFLOW: 1. lookup_user_by_email({ email: "[email protected]" }) → get user.id 2. open_slack_dm({ user: "U1234567890" }) → get DM channel + verified recipient 3. post_slack_message({ channel: "D...", text: "...", intended_recipient: "U1234567890" })

Post a message to a Slack channel as yourself. DM SAFETY: For direct messages (D... channels), intended_recipient (the recipient User ID) is REQUIRED. Without it the message is NOT sent — a DM has no visible recipient name, so sending unverified risks reaching the wrong person. The tool also refuses to send if intended_recipient does not match the actual DM recipient. To get a User ID use lookup_user_by_email, then open_slack_dm for their DM channel. PARAMETERS: channel, text, intended_recipient. Do not use channel_id or message — these are not the parameter names. Posted as the user — messages are editable in Slack.

Reply to an existing message thread in Slack as yourself. PARAMETERS: channel, thread_ts, text. The thread_ts comes from ts_slack / thread_ts_slack on a message returned by get_slack_channel_history.

Schedule a message to be posted at a future time. post_at is a Unix timestamp in SECONDS (not ms). Max 30 scheduled messages per channel per 5 minutes. Max 120 days in advance.

Search messages across all channels in the Slack workspace. Requires user authorization (search:read scope). Supports Slack search modifiers: - from:@username — Messages from a specific user - in:#channel — Messages in a specific channel - before:YYYY-MM-DD / after:YYYY-MM-DD — Date filters - has:link / has:reaction — Content filters Set to_me=true to prepend "to:@<your_username>" automatically.

Send yourself a Slack note that actually notifies you. This sends a direct message from the Slack app to you, so Slack treats it as a real notification. It is separate from your own self-DM "notes to self" space — same idea, different conversation, fewer mysteriously silent messages. PARAMETER: text. Use text, not message, note, or channel.