# How to integrate Mailersend MCP with Atomic Agent

```json
{
  "title": "How to integrate Mailersend MCP with Atomic Agent",
  "toolkit": "Mailersend",
  "toolkit_slug": "mailersend",
  "framework": "Atomic Agent",
  "framework_slug": "atomic-agent",
  "url": "https://composio.dev/toolkits/mailersend/framework/atomic-agent",
  "markdown_url": "https://composio.dev/toolkits/mailersend/framework/atomic-agent.md",
  "updated_at": "2026-08-11T13:12:00.116Z"
}
```

## Introduction

Atomic Agent is an open-source AI agent that runs on your machine and supports local models through llama.cpp. Connect it to 1,500+ apps through Composio, including Mailersend.
This guide uses Atomic Agent's built-in Composio integration. You need Atomic Agent v0.5.6 or later, your own Composio API key, and a Mailersend account. See the [Atomic Agent documentation](https://atomicagent.io/docs/?cta_placement=atomic-agent-docs) for installation instructions.

## Also integrate Mailersend with

- [OpenAI Agents SDK](https://composio.dev/toolkits/mailersend/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/mailersend/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/mailersend/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/mailersend/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/mailersend/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/mailersend/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/mailersend/framework/hermes-agent)
- [Google ADK](https://composio.dev/toolkits/mailersend/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/mailersend/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/mailersend/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/mailersend/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/mailersend/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/mailersend/framework/crew-ai)
- [Pydantic AI](https://composio.dev/toolkits/mailersend/framework/pydantic-ai)
- [AutoGen](https://composio.dev/toolkits/mailersend/framework/autogen)

## TL;DR

### How Atomic Agent connects to Mailersend
Atomic Agent connects to Composio's Tool Router over Streamable HTTP MCP. It discovers the tools needed for your request, and Composio handles account authentication.
Execution and account-connection tools follow Atomic Agent's configured approval policy. Review any approval prompt before allowing an action on your connected account.

## Connect Mailersend to Atomic Agent

### Connect Mailersend to Atomic Agent
- Sign up or sign in to the [Composio dashboard](https://dashboard.composio.dev/?cta_placement=atomic-agent-api-key). Copy your API key.
- In Atomic Agent, open the Integrations tab and select Composio. Select API key, press e, paste the key, and press Enter. The tools become available immediately, without a restart.
- Ask Atomic Agent to do something in Mailersend. It searches Composio for the right tool.
- On first use, open the sign-in link returned in the chat. Connect your Mailersend account, then return to Atomic Agent to continue.
### Headless setup
Add the following line to ~/.atomic-agent/.env, replacing YOUR_COMPOSIO_API_KEY with your key. Start Atomic Agent after saving the file.

```bash
COMPOSIO_API_KEY=YOUR_COMPOSIO_API_KEY
```

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

The Mailersend MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mailersend account. It provides structured and secure access to your transactional email infrastructure, so your agent can perform actions like sending emails, managing domains, configuring webhooks, and monitoring API usage on your behalf.
- Seamless domain management: Register new sending domains, verify their status, and retrieve detailed configuration information to ensure reliable email delivery.
- Automated email and SMTP user setup: Quickly create SMTP users and API tokens as needed for secure and scalable application integration.
- Webhook configuration and event tracking: Set up and delete webhooks to monitor real-time email events such as sent, delivered, or opened messages, enabling proactive workflows and notifications.
- Recipient and quota insights: List recipients for specific domains and monitor your API usage to stay within account limits and optimize deliverability.
- Centralized resource discovery: Retrieve general API resources and overview endpoints to streamline Mailersend integration and administration directly from your agent.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `MAILERSEND_CREATE_DOMAIN` | Create Sending Domain | Tool to add a new sending domain to MailerSend. Use when you need to register and configure a domain before sending emails. |
| `MAILERSEND_CREATE_SMTP_USER` | Create SMTP User | Tool to create a new SMTP user. Use after domain setup to obtain SMTP credentials. |
| `MAILERSEND_CREATE_TOKEN` | Create API Token | Creates a new API token with specified scopes (permissions) for a domain. The token allows programmatic access to MailerSend API endpoints based on granted scopes. WARNING: The token value is only displayed once upon creation and cannot be retrieved later. |
| `MAILERSEND_CREATE_WEBHOOK` | Create Webhook | Tool to create a new webhook for a MailerSend domain. Use after you have a domain ID and need to receive event notifications like sent, delivered, opened, etc. |
| `MAILERSEND_DELETE_WEBHOOK` | Delete Webhook | Tool to delete an existing webhook. Use when the webhook is no longer needed. Returns empty response on successful deletion (HTTP 204). |
| `MAILERSEND_GET_API_QUOTA` | Get API Quota | Tool to retrieve current API usage quota. Use when monitoring API rate limits to avoid exceeding allowed calls. |
| `MAILERSEND_GET_DOMAIN` | Get Domain | Tool to retrieve detailed information about a specific sending domain in MailerSend. Returns domain verification status (DKIM, SPF, MX, tracking), settings (click/open tracking, paused status), and metadata (creation/update timestamps). Use this when you need to check if a domain is properly verified and configured for sending emails, or to review domain-specific tracking settings. Note: For detailed DNS record values, use the Get Domain DNS Records action. |
| `MAILERSEND_GET_DOMAIN_RECIPIENTS` | List Domain Recipients | Tool to list recipients for a domain. Use after obtaining the domain ID to view recipients with optional pagination. |
| `MAILERSEND_GET_DOMAINS` | Get sending domains | Retrieve a paginated list of all sending domains configured in your MailerSend account. Use this to: - View all domains available for sending emails - Check domain verification and DNS status - Filter by verification status to find verified or unverified domains - Review domain settings like tracking and sending preferences Returns domain details including verification status, DNS configuration, and tracking settings. |
| `MAILERSEND_GET_GENERAL_RESOURCES` | Get general API resources | Tool to retrieve general API resources and information. Use when you need an overview of all MailerSend endpoints before constructing specific calls. |
| `MAILERSEND_GET_IDENTITIES` | List Sender Identities | Retrieves a paginated list of sender identities configured in your MailerSend account. Sender identities are the email addresses or domains authorized to send emails through MailerSend. Each identity includes verification status, reply-to configuration, domain association, and optional personal notes. Use this tool to discover available sender identities before sending emails or to verify which identities are ready for use. Returns: Paginated list of identity objects with metadata including verification status, domain details, and navigation links for pagination. |
| `MAILERSEND_GET_MESSAGES` | Get sent messages | Tool to retrieve a paginated list of sent messages. Use after sending emails to view message logs. |
| `MAILERSEND_GET_RECIPIENTS` | Get email recipients | Tool to retrieve a list of email recipients. Use when you need to list and filter recipients by list ID or search term. |
| `MAILERSEND_GET_SMS_ACTIVITY` | Get SMS Activity | Tool to retrieve SMS activity logs. Use when you need to fetch delivery status and logs of sent SMS messages. |
| `MAILERSEND_GET_SMS_INBOUNDS` | Get SMS Inbounds | Retrieve inbound SMS route configurations. Inbound routes define rules for forwarding incoming SMS messages to webhook URLs based on message content filters. Use this action when you need to: - List all configured SMS inbound routes - Filter routes by SMS number or enabled status - Review webhook forwarding configurations and filter rules |
| `MAILERSEND_GET_SMS_MESSAGES` | List SMS Messages | Retrieves a paginated list of SMS messages sent through the MailerSend API. Returns message details including sender, recipients, content, status, and timestamps. Use this to review sent SMS messages and track their delivery status. Note: For detailed activity tracking with filters (date ranges, status, phone numbers), use the SMS Activity endpoint instead. |
| `MAILERSEND_GET_SMS_NUMBERS` | Get SMS Numbers | Tool to retrieve a paginated list of SMS phone numbers. Use after purchasing numbers to fetch available SMS numbers. |
| `MAILERSEND_GET_SMS_RECIPIENTS` | Get SMS recipients | Tool to retrieve a list of SMS recipients. Use when you need to list and paginate SMS recipients, optionally filtering by SMS number ID and/or recipient status. |
| `MAILERSEND_GET_SMTP_USERS` | Get SMTP users | Tool to retrieve a list of SMTP users. Use when you need to list and paginate SMTP users. |
| `MAILERSEND_GET_TEMPLATES` | Get email templates | Retrieves a paginated list of email templates from your MailerSend account. Use this tool when you need to: - List all available email templates - Filter templates by domain ID - Browse templates with pagination - Check template details like name, type, and creation date Returns template metadata including IDs, names, types, and timestamps. For full template content, use a separate get single template endpoint. |
| `MAILERSEND_GET_TOKENS` | Get API Tokens | Retrieves a paginated list of API tokens associated with your MailerSend account. Returns token details including ID, name, status, creation date, and assigned scopes/permissions. Requires 'tokens_full' scope. |
| `MAILERSEND_GET_USERS` | Get users | Tool to retrieve a list of users associated with your account. Use after authenticating with a valid API token. |
| `MAILERSEND_GET_WEBHOOKS` | List webhooks | Tool to retrieve a list of webhooks. Use when you need to list and paginate all configured webhooks, optionally filtering by domain. |

## Supported Triggers

None listed.

## Troubleshooting

### Why is my API key rejected?

Copy the key directly from the Composio dashboard. Atomic Agent requires ASCII characters because it sends the key in an HTTP header. Remove any extra characters introduced when copying.

### Why are Composio tools unavailable after saving a key?

Check that you use Atomic Agent v0.5.6 or later and that Composio is enabled in your configuration. A "composio": { "enabled": false } setting disables the integration while keeping the saved key on disk.

### Does Composio have a free plan?

The Hobby plan includes 100,000 tool calls per month. Composio-managed OAuth apps have a lower included allowance. See [Composio pricing](/pricing) for the current limits that apply to your connection.

## Complete Code

None listed.

## Conclusion

### Use Mailersend from Atomic Agent
With your account connected, ask Atomic Agent to work with Mailersend in natural language. You can connect more apps through the same Composio integration as you need them.
Visit the [Atomic Agent website](https://atomicagent.io/?cta_placement=atomic-agent-site) or inspect the [Atomic Agent source code](https://github.com/AtomicBot-ai/atomic-agent?cta_placement=atomic-agent-repo).

## How to build Mailersend MCP Agent with another framework

- [OpenAI Agents SDK](https://composio.dev/toolkits/mailersend/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/mailersend/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/mailersend/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/mailersend/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/mailersend/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/mailersend/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/mailersend/framework/hermes-agent)
- [Google ADK](https://composio.dev/toolkits/mailersend/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/mailersend/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/mailersend/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/mailersend/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/mailersend/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/mailersend/framework/crew-ai)
- [Pydantic AI](https://composio.dev/toolkits/mailersend/framework/pydantic-ai)
- [AutoGen](https://composio.dev/toolkits/mailersend/framework/autogen)

## Related Toolkits

- [Gmail](https://composio.dev/toolkits/gmail) - Gmail is Google's email service with powerful spam protection, search, and G Suite integration. It keeps your inbox organized and makes communication fast and reliable.
- [Outlook](https://composio.dev/toolkits/outlook) - Outlook is Microsoft's email and calendaring platform for unified communications and scheduling. It helps users stay organized with powerful email, contacts, and calendar management.
- [Slack](https://composio.dev/toolkits/slack) - Slack is a channel-based messaging platform for teams and organizations. It helps people collaborate in real time, share files, and connect all their tools in one place.
- [Gong](https://composio.dev/toolkits/gong) - Gong is a platform for video meetings, call recording, and team collaboration. It helps teams capture conversations, analyze calls, and turn insights into action.
- [Microsoft teams](https://composio.dev/toolkits/microsoft_teams) - Microsoft Teams is a collaboration platform that combines chat, meetings, and file sharing within Microsoft 365. It keeps distributed teams connected and productive through seamless virtual communication.
- [Slackbot](https://composio.dev/toolkits/slackbot) - Slackbot is a conversational automation tool for Slack that handles reminders, notifications, and automated responses. It boosts team productivity by streamlining onboarding, answering FAQs, and managing timely alerts—all right inside Slack.
- [2chat](https://composio.dev/toolkits/_2chat) - 2chat is an API platform for WhatsApp and multichannel text messaging. It streamlines chat automation, group management, and real-time messaging for developers.
- [Agent mail](https://composio.dev/toolkits/agent_mail) - Agent mail provides AI agents with dedicated email inboxes for sending, receiving, and managing emails. It empowers agents to communicate autonomously with people, services, and other agents—no human intervention needed.
- [Android Texter](https://composio.dev/toolkits/android_texter) - Android Texter is an API service that connects Android phones to SMS, MMS, contacts, and device data. Use it to automate mobile messaging without building your own phone-to-API bridge.
- [Basecamp](https://composio.dev/toolkits/basecamp) - Basecamp is a project management and team collaboration tool by 37signals. It helps teams organize tasks, share files, and communicate efficiently in one place.
- [Blooio](https://composio.dev/toolkits/blooio) - Blooio is a stable v2 API platform for messaging, chats, contacts, groups, phone numbers, and account analytics. It gives teams a clean way to build reliable communication workflows without stitching together fragile custom APIs.
- [CallOnTheGo](https://composio.dev/toolkits/callonthego) - CallOnTheGo is a telephony API for managing phone numbers, caller IDs, suppression lists, audio assets, contact lists, and Voice AI campaigns. It provides programmatic control over calling infrastructure and campaign automation for scalable voice outreach.
- [Carbon Voice MCP](https://composio.dev/toolkits/carbon_voice_mcp) - Carbon Voice MCP is a voice-first collaboration platform for messages, conversations, and workflows. Use it to centralize voice communications and streamline team collaboration.
- [CardClan](https://composio.dev/toolkits/cardclan) - CardClan is a digital card platform for creating and sending personalized team cards. Use it to celebrate moments, share card links, and manage card workflows without extra coordination.
- [Chatwork](https://composio.dev/toolkits/chatwork) - Chatwork is a team communication platform with group chats, file sharing, and task management. It helps businesses boost collaboration and streamline productivity.
- [Clickmeeting](https://composio.dev/toolkits/clickmeeting) - ClickMeeting is a cloud-based platform for running online meetings and webinars. It helps businesses and individuals host, manage, and engage virtual audiences with ease.
- [Confluence](https://composio.dev/toolkits/confluence) - Confluence is Atlassian's team collaboration and knowledge management platform. It helps your team organize, share, and update documents and project content in one secure workspace.
- [Daily](https://composio.dev/toolkits/daily) - Daily is a WebRTC video and audio API platform for building rooms, meetings, recordings, live streams, transcriptions, and telephony. It gives developers reliable real-time media infrastructure without managing complex conferencing stacks.
- [Dailybot](https://composio.dev/toolkits/dailybot) - DailyBot streamlines team collaboration with chat-based standups, reminders, and polls. It keeps work flowing smoothly in your favorite messaging platforms.
- [Dialmycalls](https://composio.dev/toolkits/dialmycalls) - Dialmycalls is a mass notification service for sending voice and text messages to contacts. It helps teams and organizations quickly broadcast urgent alerts and updates.

## Frequently Asked Questions

### What are the differences in Tool Router MCP and Mailersend MCP?

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

### Can I use Tool Router MCP with Atomic Agent?

Yes, you can. Atomic Agent 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 Mailersend tools.

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

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

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