How to integrate Slackbot MCP with Mastra AI

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Introduction

This guide walks you through connecting Slackbot to Mastra AI using the Composio tool router. By the end, you'll have a working Slackbot agent that can send daily standup reminder to #engineering, add a custom emoji for our new logo, archive the #old-projects channel this week through natural language commands.

This guide will help you understand how to give your Mastra AI agent real control over a Slackbot account through Composio's Slackbot MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Slackbot with

TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Slackbot tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Slackbot tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your Slackbot agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

What is the Slackbot MCP server, and what's possible with it?

The Slackbot MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Slackbot account. It provides structured and secure access to your Slack workspace, so your agent can automate reminders, manage conversations, add emoji reactions, organize channels, and streamline team notifications on your behalf.

  • Automated reminders and notifications: Ask your agent to create timely Slack reminders for you or your team using natural language or custom schedules—never miss a deadline or meeting again.
  • Message reactions and engagement: Let your agent add emoji reactions to messages, star important items, or highlight key conversations to keep team morale up and draw attention where needed.
  • Channel and conversation management: Have your agent archive inactive channels, close direct messages, or organize your workspace by cleaning up conversations—all with just a simple command.
  • Custom emoji and file integration: Direct your agent to add new custom emoji, set emoji aliases, or reference external files (like Google Drive docs) for richer, more expressive communication.
  • Participant and workflow automation: Empower your agent to add call participants, automate onboarding flows, or handle repetitive Slack tasks to keep your team focused and productive.

Supported Tools & Triggers

Tools
Triggers
Add call participantsRegisters new participants added to a Slack call.
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.
Add a remote fileAdds a reference to an external file (e.
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 Slack CanvasCreates a new Slack Canvas with the specified title and optional content.
Create channelInitiates a public or private channel-based conversation in a Slack workspace.
Create a Slack user groupCreates a new User Group (often referred to as a subteam) in a Slack workspace.
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 Slack CanvasDeletes a Slack Canvas permanently and irreversibly.
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 file commentDeletes a specific comment from a file in Slack; this action is irreversible.
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 scheduled chat messageDeletes a pending, unsent scheduled message from the specified Slack channel, identified by its `scheduled_message_id`.
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.
Download Slack fileTool to download Slack file content and convert it to a publicly accessible URL.
Edit Slack CanvasEdits a Slack Canvas with granular control over content placement.
Share file public urlEnables public sharing for an existing Slack file by generating a publicly accessible URL; this action does not create new files.
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.
End a callEnds an ongoing Slack call, identified by its ID (obtained from `calls.
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.
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.
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; requires the users:read.
Find usersFind users in a Slack workspace by any criteria - email, name, display name, or other text.
Fetch bot user informationFetches information for a specified, existing Slack bot user; will not work for regular user accounts or other integration types.
Retrieve call informationRetrieves a point-in-time snapshot of a specific Slack call's information.
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 via the files.
Retrieve team profile detailsRetrieves all profile field definitions for a Slack team, optionally filtered by visibility, to understand the team's profile structure.
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.
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 with profile details, status, and team memberships in a Slack workspace; data may not be real-time.
List conversationsList 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.
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 Slack filesLists files and their metadata within a Slack workspace, filterable by user, channel, timestamp, or type; returns metadata only, not file content.
List pinned items in a channelRetrieves all messages and files pinned to a specified channel; the caller must have access to this channel.
List remindersLists all reminders with their details for the authenticated Slack user; returns an empty array if no reminders exist (valid state, not an error).
List remote filesRetrieve information about a team's remote files.
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 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.
Lookup Canvas SectionsLooks up section IDs in a Slack Canvas for use with targeted edit operations.
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 call participantsRegisters participants removed from a Slack call.
Remove reaction from itemRemoves an emoji reaction from a message, file, or file comment in Slack.
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 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.
Rename a conversationRenames a Slack channel, automatically adjusting the new name to meet naming conventions (e.
Retrieve conversation informationRetrieves metadata for a Slack conversation by ID (e.
Get conversation membersRetrieves a paginated list of active member IDs (not names, emails, or presence) for a specified Slack public channel, private channel, DM, or 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 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 all contentTool to search all messages and files.
Search messagesWorkspace‑wide Slack message search with date ranges and filters.
Send ephemeral messageSends an ephemeral message visible only to the specified `user` in a channel; other channel members cannot see it.
Share a me message in a channelSends a 'me message' (e.
Send messagePosts 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.
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 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 conversation topicSets or updates the topic for a specified Slack conversation.
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.
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.
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 call informationUpdates the title, join URL, or desktop app join URL for an existing Slack call identified by its ID.
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 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 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 SlackUpload files, images, screenshots, documents, or any media to Slack channels or threads.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Prerequisites

Before starting, make sure you have:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach Slackbot through MCP.

Install dependencies

bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session

Create a Tool Router session for Slackbot

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["slackbot"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Slackbot MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "slackbot" for Slackbot access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the Slackbot toolkit

Create the Mastra agent

typescript
const agent = new Agent({
    name: "slackbot-mastra-agent",
    instructions: "You are an AI agent with Slackbot tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\n");

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: "> ",
});

rl.prompt();

rl.on("line", async (userInput: string) => {
  const trimmedInput = userInput.trim();

  if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
    console.log("\nGoodbye!");
    rl.close();
    process.exit(0);
  }

  if (!trimmedInput) {
    rl.prompt();
    return;
  }

  messages.push({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        slackbot: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and Slackbot toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with Slackbot and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({ apiKey: composioAPIKey as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["slackbot"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      slackbot: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "slackbot-mastra-agent",
    instructions: "You are an AI agent with Slackbot tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: "> ",
  });

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { slackbot: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with Slackbot through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows

How to build Slackbot MCP Agent with another framework

FAQ

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

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

Can I use Tool Router MCP with Mastra AI?

Yes, you can. Mastra AI 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 Slackbot tools.

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

Yes, absolutely. You can configure which Slackbot 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 Slackbot data and credentials are handled as safely as possible.

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