Get all messages in a thread given a channel ID and the parent message timestamp.

Use this to read a full conversation thread before replying to it. The thread_ts is the timestamp of the parent message that started the thread.

Get the history of a channel with pagination support. Limit parameter controls max messages to fetch (default 1000).

Optional date filtering (accepts ISO 8601 dates or Unix timestamps):

• oldest: Only messages after this date (e.g., "2024-01-15" or "2024-01-15T10:30:00")

• latest: Only messages before this date (e.g., "2024-01-20" or "2024-01-20T18:00:00")

• include_threads: If True, also fetch all replies in threads (default False)

Note: For date-only formats, 'oldest' defaults to start of day (00:00:00) and 'latest' to end of day (23:59:59).

Get the channel ID by channel name. The channel name can be with or without the # prefix.

Refresh the channel cache. Use this when new channels are created or if channel lookups are failing.

Clear the user cache. Use this when user handles are outdated or if user lookups are failing. Returns the number of cached entries cleared.

Resolve a Slack user ID from a name, @handle, or email address.

Searches the full workspace member list (cached for 24h). Returns up to 5 matches sorted by relevance: exact handle > exact email > case-insensitive name > partial substring match. Each result contains id, handle, real_name, display_name, and email.

Post a message to a channel. Optionally pass Block Kit blocks as a JSON string for rich formatting (e.g. nested lists via rich_text blocks). When blocks is provided, message is used as the plaintext fallback.

Post a command to a channel.

Add a reaction to a message.

Get reactions to a message.

Checks authentication & identity.

Join a channel.

Create a new Slack channel.

Args: name: Channel name (will be sanitized: lowercase, hyphens, no spaces) is_private: Create as private channel (default: False for public)

Returns: Channel ID on success, None on failure

Invite multiple users to a channel.

Args: channel_id: Target channel ID (C...) user_ids: List of user IDs to invite (U...)

Returns: True if all invitations succeeded, False otherwise

Rename a Slack channel.

Args: channel_id: Target channel ID (C...) new_name: New channel name (will be sanitized: lowercase, hyphens, no spaces)

Returns: True if rename succeeded, False otherwise

List channels the authenticated user is a member of.

Uses Slack's users.conversations API. By default returns public and private channels only. To include DMs and group DMs, set types to e.g. "public_channel,private_channel,im,mpim".

Clear all users from a Slack usergroup.

Since Slack API doesn't support empty usergroups, this uses a workaround by setting the usergroup to contain only a randomly selected deleted user. This effectively clears the usergroup.

Args: usergroup_id: The usergroup ID (S...) to clear

Returns: True if usergroup was cleared successfully, False otherwise

Set the members of a Slack usergroup, replacing the current membership entirely.

Args: usergroup_id: The usergroup ID (S...) to update user_ids: List of user IDs (U...) that should be the members. Must contain at least one user — use clear_usergroup to remove all members.

Returns: True if the membership was updated successfully, False otherwise

Send a direct message to a user. Optionally pass Block Kit blocks as a JSON string for rich formatting (e.g. nested lists via rich_text blocks). When blocks is provided, message is used as the plaintext fallback.

Send a message to a group DM (multi-party direct message).

Args: user_ids: List of 2+ user IDs to include in group DM message: Message text to send

Returns: True if message sent successfully, False otherwise

Search for messages in the workspace with pagination support. Limit parameter controls max results to fetch (default 1000).

Search for messages within a specific channel.

Uses Slack's search API with an 'in:' filter.

Args: channel_id: The channel ID to search within. query: The search query text. sort: Sort results by "timestamp" (newest first) or "score" (relevance). limit: Max number of results to return (default 100).