Adds a reference to an external file (e.g., Google Drive, Dropbox) to Slack for discovery and sharing, requiring a unique external_id and an external_url accessible by Slack.

Removes the Slack reference to an external file (which must have been previously added via the remote files API), specified by either its external_id or file ID (one of which is required), without deleting the actual external file.

Updates metadata or content details for an existing remote file in Slack; this action cannot upload new files or change the fundamental file type.

Registers new participants added to a Slack call.

Adds a specified emoji reaction to an existing message in a Slack channel, identified by its timestamp; does not remove or retrieve reactions.

Archives a Slack conversation by its ID, rendering it read-only and hidden while retaining history, ideal for cleaning up inactive channels; be aware that some channels (like #general or certain DMs) cannot be archived and this may impact connected integrations.

Closes a Slack direct message (DM) or multi-person direct message (MPDM) channel, removing it from the user's sidebar without deleting history; this action affects only the calling user's view.

Creates a Slack reminder with specified text and time; time accepts Unix timestamps, seconds from now, or natural language (e.g., 'in 15 minutes', 'every Thursday at 2pm').

Creates a new Slack Canvas with the specified title and optional content.

Initiates a public or private channel-based conversation in a Slack workspace. Immediately creates the channel; invoke only after explicit user confirmation.

Creates a new User Group (often referred to as a subteam) in a Slack workspace.

Customizes URL previews (unfurling) in a specific Slack message using a URL-encoded JSON in unfurls to define custom content or remove existing previews.

Deletes a Slack Canvas permanently and irreversibly. Always confirm with the user before calling this tool.

Permanently deletes an existing file from a Slack workspace using its unique file ID; this action is irreversible and also removes any associated comments or shares.

Deletes a specific comment from a file in Slack; this action is irreversible.

Deletes an existing Slack reminder, typically when it is no longer relevant or a task is completed; this operation is irreversible.

Deletes a message, identified by its channel ID and timestamp, from a Slack channel, private group, or direct message conversation; the authenticated user or bot must be the original poster.

Deletes a pending, unsent scheduled message from the specified Slack channel, identified by its scheduled_message_id.

Disables a specified, currently enabled Slack User Group by its unique ID, effectively archiving it by setting its 'date_delete' timestamp; the group is not permanently deleted and can be re-enabled.

Tool to download Slack file content and convert it to a publicly accessible URL. Use when you need to retrieve and download files that have been shared in Slack channels or conversations.

Edits a Slack Canvas with granular control over content placement. Supports replace, insert (before/after/start/end) operations for flexible content management.

Enables public sharing for an existing Slack file by generating a publicly accessible URL; this action does not create new files. Once enabled, the file is accessible to anyone with the URL — verify intent before sharing sensitive or confidential files.

Enables a disabled User Group in Slack using its ID, reactivating it for mentions and permissions; this action only changes the enabled status and cannot create new groups or modify other properties.

Ends an ongoing Slack call, identified by its ID (obtained from calls.add), optionally specifying the call's duration.

Fetches a chronological list of messages and events from a specified Slack conversation, accessible by the authenticated user/bot, with options for pagination and time range filtering. IMPORTANT LIMITATION: This action only returns messages from the main channel timeline. Threaded replies are NOT returned by this endpoint. To retrieve threaded replies, use the SLACK_FETCH_MESSAGE_THREAD_FROM_A_CONVERSATION action (conversations.replies API) instead. The oldest/latest timestamp filters work reliably for filtering the main channel timeline, but cannot be used to retrieve individual threaded replies - even if you know the exact reply timestamp, setting oldest=latest to that timestamp will return an empty messages array. To get threaded replies: 1. Use this action to get parent messages (which include thread_ts, reply_count, latest_reply fields) 2. Use SLACK_FETCH_MESSAGE_THREAD_FROM_A_CONVERSATION with the parent's thread_ts to fetch all replies in that thread

Fetches reactions for a Slack message, file, or file comment. Exactly one identifier path must be provided: channel+timestamp, file, or file_comment. Mixing identifiers (e.g., providing both channel+timestamp and file) causes errors. If the response omits the reactions field, the item has zero reactions.

Retrieves replies to a specific parent message in a Slack conversation, using the channel ID and the parent message's timestamp (ts). Note: The parent message in the response contains metadata (reply_count, reply_users, latest_reply) that indicates expected thread activity. If the returned messages array contains fewer replies than reply_count indicates, check: (1) has_more=true means pagination is needed, (2) recently posted replies may have timing delays, (3) some replies may be filtered by permissions or deleted. The composio_execution_message field will warn about any detected mismatches.

Fetches comprehensive metadata about the current Slack team, or a specified team if the provided ID is accessible.

Find channels in a Slack workspace by any criteria - name, topic, purpose, or description. Returns channel IDs (C*/G* prefixed) required by most Slack tools — always resolve names to IDs here before passing to other tools. NOTE: This action searches channels and conversations visible to the authenticated user. Empty results may indicate: - No channels match the search query in name, topic, or purpose - The target private channel or DM is not accessible to the authenticated user because they are not a member - The connection lacks required read scopes (channels:read, groups:read, im:read, mpim:read). If empty, retry with exact_match=false or exclude_archived=false to avoid false negatives. In large workspaces, paginate using next_cursor to avoid missing matches. Check 'composio_execution_message' and 'total_channels_searched' in the response for details.

Retrieves the Slack user object for an active user by their registered email address; requires the users:read.email OAuth scope. Fails with 'users_not_found' if the email is unregistered, the user is inactive, the account is a guest, or the email is hidden by workspace privacy settings.

Find users in a Slack workspace by any criteria - email, name, display name, or other text. Includes optimized email lookup for exact email matches. Zero results may reflect email visibility restrictions or workspace policies, not global absence. Repeated calls may trigger HTTP 429; honor the Retry-After header.

Fetches information for a specified, existing Slack bot user; will not work for regular user accounts or other integration types.

Retrieves a point-in-time snapshot of a specific Slack call's information.

Retrieves detailed information for an existing Slack reminder specified by its ID; this is a read-only operation.

Retrieve information about a remote file added to Slack via the files.remote API. Does not work for standard Slack-hosted file uploads.

Retrieves all profile field definitions for a Slack team, optionally filtered by visibility, to understand the team's profile structure.

Retrieves a user's current Do Not Disturb status.

Retrieves a Slack user's current real-time presence (e.g., 'active', 'away') to determine their availability, noting this action does not provide historical data or status reasons.

Invites users to an existing Slack channel using their valid Slack User IDs. Response is always HTTP 200; inspect ok, error, and errors fields to confirm users were added.

Joins an existing Slack conversation (public channel, private channel, or multi-person direct message) by its ID, if the authenticated user has permission. Joining an already-joined channel returns a non-fatal no-op response. Private or restricted channel joins may fail with a permission error.

Leaves a Slack conversation given its channel ID; fails if leaving as the last member of a private channel or if used on a Slack Connect channel.

Lists conversations available to the user with various filters and search options. Always use resolved channel_id (not display names) for downstream operations, as names may be non-unique. The created field in results is a Unix epoch timestamp (UTC). Pagination across large workspaces may return HTTP 429 with a Retry-After header; honor the delay and resume from the last successful cursor.

Retrieves a paginated list of all users with profile details, status, and team memberships in a Slack workspace; data may not be real-time. Filter response fields is_bot, is_app_user, and deleted to build human-only rosters. Profile fields like email and phone may be absent depending on OAuth scopes and workspace privacy settings. Guest/restricted accounts may be omitted based on scopes—do not treat results as a complete directory. High-frequency calls risk HTTP 429; honor the Retry-After header and throttle to ~1–2 requests/second. Use stable user IDs rather than display names for mapping. Prefer SLACK_FIND_USERS for targeted lookups; cache results to avoid full-workspace fetches.

List conversations (channels/DMs) accessible to a specified user (or the authenticated user if no user ID is provided), respecting shared membership for non-public channels. Returns conversation IDs (C* for channels, G* for group DMs), not display names. Absence of private channels, DMs, or MPIMs from results indicates token scope or membership limits, not that the conversation is nonexistent.

Retrieves all custom emojis for the Slack workspace (image URLs or aliases), not standard Unicode emojis; does not include usage statistics or creation dates.

Lists files and their metadata within a Slack workspace, filterable by user, channel, timestamp, or type; returns metadata only, not file content. Results are limited to files visible to the authenticated user — files in private channels or restricted to certain members require appropriate membership and permissions. For large workspaces, check paging.pages in the response to determine total pages when paginating.

Retrieves all messages and files pinned to a specified channel; the caller must have access to this channel.

Lists all reminders with their details for the authenticated Slack user; returns an empty array if no reminders exist (valid state, not an error). Reminder text is not unique—perform client-side matching on returned objects before extracting a reminder ID for use with SLACK_MARK_REMINDER_AS_COMPLETE or SLACK_DELETE_A_SLACK_REMINDER.

Retrieve information about a team's remote files.

Retrieves a list of all user IDs within a specified Slack user group, with an option to include users from disabled groups.

Lists user groups in a Slack workspace, including user-created and default groups; results for large workspaces may be paginated.

Lists all reactions added by a specific user to messages, files, or file comments in Slack, useful for engagement analysis when the item content itself is not required. Results are paginated; check response_metadata.next_cursor and iterate with the cursor parameter to retrieve complete reaction history.

Looks up section IDs in a Slack Canvas for use with targeted edit operations. Section IDs are needed for insert_after, insert_before, delete, and section-specific replace operations.

Opens or resumes a Slack direct message (DM) or multi-person direct message (MPIM) by providing either user IDs or an existing channel ID. Returns already_open=true when the DM exists — treat as success and reuse the returned channel.id (starts with 'D') for subsequent SLACK_SEND_MESSAGE calls; passing a username, email, or user ID directly to SLACK_SEND_MESSAGE causes channel_not_found. Avoid redundant calls when an existing DM channel ID is available.

Pins a message to a specified Slack channel; the message must not already be pinned.

Registers participants removed from a Slack call.

Removes an emoji reaction from a message, file, or file comment in Slack. Provide exactly one targeting method: channel+timestamp together, file, or file_comment. Mixing methods or omitting all returns invalid_arguments.

Removes a specified user from a Slack conversation (channel); the caller must have permissions to remove users and cannot remove themselves using this action.

Renames a Slack channel, automatically adjusting the new name to meet naming conventions (e.g., converting to lowercase), which may affect integrations using the old name.

Retrieves metadata for a Slack conversation by ID (e.g., name, purpose, creation date, with options for member count/locale), excluding message content. The channel parameter is effectively required. Private channels, DMs, or channels where the app lacks membership may return restricted data; check is_archived and is_member fields in the response to diagnose access issues. Bulk lookups may trigger HTTP 429 rate limiting; honor the Retry-After response header.

Retrieves a paginated list of active member IDs (not names, emails, or presence) for a specified Slack public channel, private channel, DM, or MPIM. Returns only user IDs; use a user-lookup tool to enrich member data.

Retrieves a Slack user's current Do Not Disturb (DND) status to determine their availability before interaction; any specified user ID must be a valid Slack user ID.

Retrieves detailed metadata and paginated comments for a specific Slack file ID; does not download file content.

Retrieves comprehensive information for a valid Slack user ID, excluding message history and channel memberships. Sensitive fields like email and phone require the users:read.email scope and may be silently omitted based on workspace privacy policies.

Retrieves profile information for a specified Slack user (defaults to the authenticated user if user ID is omitted); a provided user ID must be valid. Sensitive fields like email and phone may be silently omitted if required scopes (e.g., users:read.email) are not granted or workspace privacy policies restrict access.

Revokes a Slack file's public URL, making it private; this is a no-op if not already public and is irreversible.

Schedules a message to a Slack channel, DM, or private group for a future time (post_at), requiring text, blocks, or attachments for content; scheduling is limited to 120 days in advance.

Tool to search all messages and files. Use when you need unified content search across channels and files in one call. Results are scoped to content visible to the authenticated token; missing hits in private or restricted channels reflect permission/membership gaps. Response separates messages and files into distinct sections — explicitly read the files section for document results. Results are index-based and may lag several minutes behind real-time; use SLACK_FETCH_CONVERSATION_HISTORY for near-real-time per-channel coverage. Paginated searches exceeding ~1 req/sec may return HTTP 429 too_many_requests; honor the Retry-After header and resume from the last page.

Workspace‑wide Slack message search with date ranges and filters. Use query modifiers (e.g., in:#channel, from:@user, before/after:YYYY-MM-DD), sorting (score/timestamp), and pagination.

Sends an ephemeral message visible only to the specified user in a channel; other channel members cannot see it. Both the bot and the target user must be members of the specified channel.

Sends a 'me message' (e.g., '/me is typing') to a Slack channel, where it's displayed as a third-person user action; messages are plain text and the channel must exist and be accessible.

Posts a message to a Slack channel, DM, or private group; requires at least one content field (markdown_text, text, blocks, or attachments) — omitting all causes a no_text error. Fails with not_in_channel, channel_not_found, or channel_is_archived if the bot lacks access. Body limit ~4000 characters. Rate-limited at ~1 req/sec (HTTP 429, honor Retry-After). Not idempotent — duplicate calls post duplicate messages.

Sets the purpose (a short description of its topic/goal, displayed in the header) for a Slack conversation; the calling user must be a member.

Marks a message, specified by its timestamp (ts), as the most recently read for the authenticated user in the given channel, provided the user is a member of the channel and the message exists within it.

Sets or updates the topic for a specified Slack conversation.

Manually sets a user's Slack presence, overriding automatic detection; this setting persists across connections but can be overridden by user actions or Slack's auto-away (e.g., after 10 mins of inactivity).

Shares a remote file, which must already be registered with Slack, into specified Slack channels or direct message conversations.

Registers a new call in Slack using calls.add for third-party call integration; created_by is required if not using a user-specific token.

Reverses conversation archival.

Unpins a message, identified by its timestamp, from a specified channel if the message is currently pinned there; this operation is destructive.

Updates the title, join URL, or desktop app join URL for an existing Slack call identified by its ID.

Updates a Slack message, identified by channel ID and ts timestamp, by modifying its text, attachments, or blocks; provide at least one content field, noting attachments/blocks are replaced if included ([] clears them).

Updates an existing Slack User Group, which must be specified by an existing usergroup ID, with new optional details such as its name, description, handle, or default channels.

Replaces all members of an existing Slack User Group with a new list of valid user IDs.

Upload files, images, screenshots, documents, or any media to Slack channels or threads. Supports all file types including images (PNG, JPG, JPEG, GIF), documents (PDF, DOCX, TXT), code files, and more. Can share files publicly in channels or as thread replies with optional comments. Large files may fail with upload_too_large; use SLACK_ADD_A_REMOTE_FILE_FROM_A_SERVICE for large uploads. If the API returns ok=false with method_deprecated, fall back to SLACK_ADD_A_REMOTE_FILE_FROM_A_SERVICE or SLACK_SEND_MESSAGE with a URL.