How to integrate Slack MCP with OpenCode

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How to integrate Slack MCP with OpenCode

This guide explains how to connect Slack MCP to OpenCode using Composio Connect, which simplifies OAuth, API changes, and reliability concerns.

There are two ways to set this up:

Also integrate Slack with

Why use Composio?

Composio provides a single MCP server or CLI tool that exposes a set of meta-tools, allowing you to:

  • Connect to 1,000+ apps with on-demand tool loading, so you do not fill your LLM context window with unnecessary tool definitions.
  • Use programmatic tool calling through a remote Bash tool, letting LLMs write their own code to handle complex tool chaining. This reduces back-and-forth for frequent tool calls.
  • Handle large tool responses outside the LLM context to keep conversations lean.

Connect Slack with OpenCode

Option 1: Using Composio CLI

1. Install Composio CLI

Install the Composio CLI, authenticate, and initialize your project:

bash
# Install the Composio CLI
curl -fsSL https://composio.dev/install | bash

# Authenticate with Composio
composio login

During login, you will be redirected to the sign-in page. Finish the flow and you are all set.

Composio CLI authorization screen

2. Authorize Slack

Once the CLI is installed, it is essentially done. Give OpenCode access to your apps with these steps:

  1. Launch OpenCode.
  2. Prompt it to "Authenticate with Slack Composio".
  3. Complete the authentication and authorization flow, and your Slack integration is all set.
  4. Start asking anything you want.

Option 2: Using Composio MCP

You can also connect Slack to OpenCode by adding Composio as an MCP server through the OpenCode CLI.

1. Add the Composio MCP server

bash
opencode mcp add

This launches an interactive prompt.

2. Fill in the fields

FieldValue
Namecomposio
Typeremote
URLhttps://connect.composio.dev/mcp
Require OAuthYes
Have client IDNo
OpenCode MCP server interactive prompt for Composio

Alternatively, you can skip the interactive prompt and paste the configuration directly into your OpenCode config file.

Open your global OpenCode config:

bash
open ~/.config/opencode/opencode.json

Add this under the mcp key and save the file.

bash
{
  "mcp": {
    "composio": {
      "type": "remote",
      "url": "https://connect.composio.dev/mcp",
      "enabled": true
    }
  }
}

3. Authenticate

Authenticate the Composio MCP server you just added:

bash
opencode mcp auth composio

This opens a browser session. Authorize Composio and you are done.

Composio browser authorization for OpenCode MCP

4. Verify installation

bash
opencode mcp list

5. Connect Slack with OpenCode

Now, in the chat, ask the agent to connect to Slack or give it any Slack-related task.

For example, ask it to:

  • "Send reminder to marketing channel at 10am"
  • "Add reaction to latest team message"
  • "Archive inactive project channel after review"

It will prompt you to authenticate and authorize access to Slack.

That is it. Composio tools are now available in OpenCode, and your Slack account is ready to use.

Supported Tools & Triggers

Tools
Triggers
Add an emoji aliasAdds an alias for an existing custom emoji in a slack enterprise grid organization.
Add a remote fileAdds a reference to an external file (e.
Add a star to an itemStars a channel, file, file comment, or a specific message in slack.
Add call participantsRegisters new participants added to a slack call.
Add emojiAdds a custom emoji to a slack workspace given a unique name and an image url; subject to workspace emoji limits.
Add reaction to messageAdds a specified emoji reaction to an existing message in a slack channel, identified by its timestamp; does not remove or retrieve reactions.
Archive a public or private channelArchives a slack public or private channel, making it read-only; the primary 'general' channel cannot be archived.
Archive a Slack conversationArchives 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.
Close conversation channelCloses 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.
Create a reminderCreates a slack reminder with specified text and time; time accepts unix timestamps, seconds from now, or natural language (e.
Create a Slack user groupCreates a new user group (often referred to as a subteam) in a slack workspace.
Create channelInitiates a public or private channel-based conversation
Create a channel-based conversationCreates a new public or private slack channel with a unique name; the channel can be org-wide, or team-specific if `team id` is given (required if `org wide` is false or not provided).
Customize URL unfurlCustomizes url previews (unfurling) in a specific slack message using a url-encoded json in `unfurls` to define custom content or remove existing previews.
Delete file commentDeletes a specific comment from a file in slack; this action is irreversible.
Delete a file by IDPermanently 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.
Delete a public or private channelPermanently and irreversibly deletes a specified public or private channel, including all its messages and files, within a slack enterprise grid organization.
Delete scheduled chat messageDeletes a pending, unsent scheduled message from the specified slack channel, identified by its `scheduled message id`.
Delete a Slack reminderDeletes an existing slack reminder, typically when it is no longer relevant or a task is completed; this operation is irreversible.
Delete a message from a chatDeletes 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.
Delete user profile photoDeletes the slack profile photo for the user identified by the token, reverting them to the default avatar; this action is irreversible and succeeds even if no custom photo was set.
Disable a Slack user groupDisables 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.
Enable a user groupEnables 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.
Share file public urlEnables public sharing for an existing slack file by generating a publicly accessible url; this action does not create new files.
End a callEnds an ongoing slack call, identified by its id (obtained from `calls.
End snoozeEnds the current user's snooze mode immediately.
End DND sessionEnds the authenticated user's current do not disturb (dnd) session in slack, affecting only dnd status and making them available; if dnd is not active, slack acknowledges the request without changing status.
Fetch bot user informationFetches information for a specified, existing slack bot user; will not work for regular user accounts or other integration types.
Fetch conversation historyFetches 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.
Fetch item reactionsFetches reactions for a slack message, file, or file comment, requiring one of: channel and timestamp; file id; or file comment id.
Retrieve conversation repliesRetrieves replies to a specific parent message in a slack conversation, using the channel id and the parent message's timestamp (`ts`).
Fetch team infoFetches comprehensive metadata about the current slack team, or a specified team if the provided id is accessible.
Fetch workspace settings informationRetrieves detailed settings for a specific slack workspace, primarily for administrators in an enterprise grid organization to view or audit workspace configurations.
Find channelsFind channels in a slack workspace by any criteria - name, topic, purpose, or description.
Lookup users by emailRetrieves the slack user object for an active user by their registered email address; fails with 'users not found' if the email is unregistered or the user is inactive.
Find usersFind users in a slack workspace by any criteria - email, name, display name, or other text.
Get channel conversation preferencesRetrieves conversation preferences (e.
Get reminder informationRetrieves detailed information for an existing slack reminder specified by its id; this is a read-only operation.
Get remote fileRetrieve information about a remote file added to slack.
Get team DND statusRetrieves a user's current do not disturb status.
Retrieve user presenceRetrieves a slack user's current real-time presence (e.
Invite users to a Slack channelInvites users to an existing slack channel using their valid slack user ids.
Invite users to channelInvites users to a specified slack channel; this action is restricted to enterprise grid workspaces and requires the authenticated user to be a member of the target channel.
Invite user to workspaceInvites a user to a slack workspace and specified channels by email; use `resend=true` to re-process an existing invitation for a user not yet signed up.
Join conversation by channel idJoins an existing slack conversation (public channel, private channel, or multi-person direct message) by its id, if the authenticated user has permission.
Leave conversation channelLeaves 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.
List all channelsLists conversations available to the user with various filters and search options.
List all usersRetrieves a paginated list of all users, including comprehensive details, profile information, status, and team memberships, in a slack workspace; data may not be real-time.
List all users in a user groupRetrieves a list of all user ids within a specified slack user group, with an option to include users from disabled groups.
List conversationsRetrieves conversations accessible to a specified user (or the authenticated user if no user id is provided), respecting shared membership for non-public channels.
List Slack filesLists files and their metadata within a slack workspace, filterable by user, channel, timestamp, or type; this action returns metadata only, not file content.
List remindersLists all reminders with their details for the authenticated slack user; returns an empty list if no reminders exist.
List remote filesRetrieve information about a team's remote files.
List scheduled messagesRetrieves a list of pending (not yet delivered) messages scheduled in a specific slack channel, or across all accessible channels if no channel id is provided, optionally filtered by time and paginated.
List pinned items in a channelRetrieves all messages and files pinned to a specified channel; the caller must have access to this channel.
List starred itemsLists items starred by a user.
List team custom emojisRetrieves all custom emojis for the slack workspace (image urls or aliases), not standard unicode emojis; does not include usage statistics or creation dates.
List user groupsLists user groups in a slack workspace, including user-created and default groups; results for large workspaces may be paginated.
List user reactionsLists 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.
List admin usersRetrieves a paginated list of admin users for a specified slack workspace.
Set user presenceManually 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.
Mark reminder as completeMarks a specific slack reminder as complete using its `reminder` id; **deprecated**: this slack api endpoint ('reminders.
Open DMOpens or resumes a slack direct message (dm) or multi-person direct message (mpim) by providing either user ids or an existing channel id.
Pin an item to a channelPins a message to a specified slack channel; the message must not already be pinned.
Remove remote fileRemoves 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.
Remove a star from an itemRemoves a star from a previously starred slack item (message, file, file comment, channel, group, or dm), requiring identification via `file`, `file comment`, `channel` (for channel/group/dm), or both `channel` and `timestamp` (for a message).
Remove user from conversationRemoves a specified user from a slack conversation (channel); the caller must have permissions to remove users and cannot remove themselves using this action.
Remove call participantsRegisters participants removed from a slack call.
Remove reaction from itemRemoves an emoji reaction from a message, file, or file comment in slack.
Rename a conversationRenames a slack channel, automatically adjusting the new name to meet naming conventions (e.
Rename an emojiRenames an existing custom emoji in a slack workspace, updating all its instances.
Rename a Slack channelRenames a public or private slack channel; for enterprise grid workspaces, the user must be a workspace admin or channel manager.
Retrieve a user's identity detailsRetrieves the authenticated user's and their team's identity, with details varying based on oauth scopes (e.
Retrieve call informationRetrieves a point-in-time snapshot of a specific slack call's information.
Retrieve conversation informationRetrieves metadata for a slack conversation by id (e.
Get conversation membersRetrieves a paginated list of active member ids for a specified slack public channel, private channel, direct message (dm), or multi-person direct message (mpim).
Retrieve user DND statusRetrieves 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.
Retrieve detailed file informationRetrieves detailed metadata and paginated comments for a specific slack file id; does not download file content.
Retrieve detailed user informationRetrieves comprehensive information for a valid slack user id, excluding message history and channel memberships.
Retrieve message permalinkRetrieves a permalink url for a specific message in a slack channel or conversation; the permalink respects slack's privacy settings.
Retrieve team profile detailsRetrieves all profile field definitions for a slack team, optionally filtered by visibility, to understand the team's profile structure.
Retrieve user profile informationRetrieves profile information for a specified slack user (defaults to the authenticated user if `user` id is omitted); a provided `user` id must be valid.
Revoke a file's public urlRevokes a slack file's public url, making it private; this is a no-op if not already public and is irreversible.
Schedule messageSchedules 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.
Search messagesWorkspace‑wide slack message search with date ranges and filters.
Send ephemeral messageSends an ephemeral message to a user in a channel.
Send messagePosts a message to a slack channel, direct message, or private group; requires content via `text`, `blocks`, or `attachments`.
Set a conversation's purposeSets the purpose (a short description of its topic/goal, displayed in the header) for a slack conversation; the calling user must be a member.
Set DND durationTurns on do not disturb mode for the current user, or changes its duration.
Set profile photoThis method allows the user to set their profile image.
Set conversation read cursorMarks 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.
Set Slack user profile informationUpdates a slack user's profile, setting either individual fields or multiple fields via a json object.
Set conversation topicSets or updates the topic for a specified slack conversation.
Share a me message in a channelSends a 'me message' (e.
Share a remote file in channelsShares a remote file, which must already be registered with slack, into specified slack channels or direct message conversations.
Start callRegisters a new call in slack using `calls.
Start real time messaging sessionInitiates a slack rtm session providing a single-use websocket url (valid 30s) for event streaming; does not set initial presence status.
Unarchive a public or private channelUnarchives a specified public or private slack channel that is currently archived, using its channel id.
Unarchive channelReverses conversation archival.
Unpin message from channelUnpins a message, identified by its timestamp, from a specified channel if the message is currently pinned there; this operation is destructive.
Update Slack user groupUpdates 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.
Update an existing remote fileUpdates metadata or content details for an existing remote file in slack; this action cannot upload new files or change the fundamental file type.
Update a Slack messageUpdates 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).
Update call informationUpdates the title, join url, or desktop app join url for an existing slack call identified by its id.
Update user group membersReplaces all members of an existing slack user group with a new list of valid user ids.
Upload or create a file in SlackUploads a file to slack, requiring either `content` (for text) or `file` (for binary data), optionally sharing it in specified `channels` or as a reply via `thread ts`.

Way Forward

Now that Slack is connected, extend your setup by connecting the other apps you already use every day, so your agent can run true cross-app workflows end to end.

  • Connect Calendar to turn threads into scheduled meetings automatically.
  • Connect Slack or Teams to post summaries, approvals, and alerts where your team works.
  • Connect Notion, Linear, Jira, or Asana to convert requests into tickets, tasks, and docs.
  • Connect Drive, Dropbox, or OneDrive to fetch, file, and share attachments without manual steps.

Start with one workflow you do repeatedly, then keep adding apps as you find new handoffs. With everything behind a single MCP endpoint, your agent can coordinate multiple tools safely and reliably in one conversation.

How to build Slack MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and Slack MCP?

With a standalone Slack MCP server, the agents and LLMs can only access a fixed set of Slack tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Slack and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with OpenCode?

Yes, you can. OpenCode fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Slack tools.

Can I manage the permissions and scopes for Slack while using Tool Router?

Yes, absolutely. You can configure which Slack scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Slack data and credentials are handled as safely as possible.

Used by agents from

Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

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