How to connect Mails so to Claude Cowork

Cowork is Anthropic's AI agent for knowledge work. Think of it as Claude Code for everything else. It works autonomously with your computer, local files, and applications to accomplish complex tasks. This guide walks you through the easiest and most secure way to connect your Mails so account to Cowork via Composio Connect, enabling it to check if this email address is valid, validate a list of emails before campaign, download results for last batch validation job, and more such actions on your behalf without compromising your account security.

Mails so logoMails so
Api Key

Mails so is an API service for email validation and verification. It helps you keep your contact lists clean, accurate, and free from invalid or risky addresses.

3 Tools

Introduction

Cowork is Anthropic's AI agent for knowledge work. Think of it as Claude Code for everything else. It works autonomously with your computer, local files, and applications to accomplish complex tasks.

This guide walks you through the easiest and most secure way to connect your Mails so account to Cowork via Composio Connect, enabling it to check if this email address is valid, validate a list of emails before campaign, download results for last batch validation job, and more such actions on your behalf without compromising your account security.

Also integrate Mails so with

Connecting Mails so to Claude Cowork

1. Open Customize

In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.

Claude Desktop connectors screen with Add custom connector selected

2. Add the Composio MCP server

Click Add custom connector and paste in the Composio MCP server URL:

bash
https://connect.composio.dev/mcp
Add custom connector dialog with Composio MCP server URL

3. Authorize in your browser

Click Connect. You'll be redirected to a browser window where you can authorize Composio to continue.

Composio authorization screen for Claude Cowork

4. Connect your Mails so account

Back in Cowork, ask the agent to connect to Mails so or give it any Mails so-related task.

For example, ask Cowork to:

  • "Check if this email address is valid"
  • "Validate a list of emails before campaign"
  • "Download results for last batch validation job"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Cowork, and your Mails so account is ready to use.

What is Claude Cowork?

Claude Cowork is Anthropic's agent for general knowledge work. It can use your computer, files, and connected applications to complete longer-running tasks across your work tools.

With Composio Connect, Cowork can securely access apps like Mails so through MCP without you sharing account credentials directly with the agent.

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

The Mails so MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mails so account. It provides structured and secure access to advanced email validation services, so your agent can perform actions like verifying single emails, running bulk checks, and retrieving validation results on your behalf.

  • Single email validation: Instantly check if an individual email address is valid and safe to use before sending important messages.
  • Bulk email validation: Submit large lists of email addresses for automated deliverability and quality checks, keeping your contact databases clean.
  • Batch results retrieval: Effortlessly fetch detailed validation outcomes for previously submitted bulk jobs, so you can review and act on the results.
  • Email list hygiene automation: Use the agent to regularly scan and validate contact lists, reducing bounce rates and improving sender reputation.
TOOLS

Supported Tools

Every Mails so action and event your agent gets out of the box.

Retrieve Batch Results

Tool to retrieve results of a bulk validation job.

Validate Bulk Emails

Tool to validate multiple email addresses in bulk.

Validate Single Email

Tool to validate a single email address.

FAQ

Frequently asked questions

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

Yes, you can. Claude Cowork 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 Mails so tools.

Yes, absolutely. You can configure which Mails so 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.

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 Mails so data and credentials are handled as safely as possible.

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