# How to integrate mailfloss MCP with Atomic Agent

```json
{
  "title": "How to integrate mailfloss MCP with Atomic Agent",
  "toolkit": "mailfloss",
  "toolkit_slug": "mailfloss",
  "framework": "Atomic Agent",
  "framework_slug": "atomic-agent",
  "url": "https://composio.dev/toolkits/mailfloss/framework/atomic-agent",
  "markdown_url": "https://composio.dev/toolkits/mailfloss/framework/atomic-agent.md",
  "updated_at": "2026-10-24T05:33:40.713Z"
}
```

## 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 mailfloss.
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 mailfloss account. See the [Atomic Agent documentation](https://atomicagent.io/docs/?cta_placement=atomic-agent-docs) for installation instructions.

## Also integrate mailfloss with

- [ChatGPT](https://composio.dev/toolkits/mailfloss/framework/chatgpt)
- [Claude Cowork](https://composio.dev/toolkits/mailfloss/framework/claude-cowork)
- [Hermes](https://composio.dev/toolkits/mailfloss/framework/hermes-agent)

## TL;DR

### How Atomic Agent connects to mailfloss
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 mailfloss to Atomic Agent

### Connect mailfloss 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 mailfloss. It searches Composio for the right tool.
- On first use, open the sign-in link returned in the chat. Connect your mailfloss 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 mailfloss MCP server, and what's possible with it?

The mailfloss MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your mailfloss account. It provides structured and secure access to email verification, batch processing, account details, and usage information, so your agent can verify email addresses, process verification batches, track job status and results, and manage stored verification records on your behalf.
- Individual email verification: Have your agent check an email address and return its Mailfloss verification verdict.
- Batch verification workflows: Direct your agent to submit groups of email addresses for verification, monitor processing status, retrieve results, or cancel pending jobs.
- Verification history: Let the agent review past verification jobs, inspect their verdict breakdowns, and filter job history by source or lifecycle status.
- Account and usage insights: Instruct your agent to check the connected API key, view account and organization details, and review verification usage for a selected period.
- Record management: Have your agent permanently erase stored verification records for specified email addresses when they are no longer needed.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `MAILFLOSS_CANCEL_BATCH_VERIFICATION` | Cancel Batch Verification | Cancel a pending or in-progress batch verification job. This irreversible operation stops remaining work and re-credits unprocessed emails; it is a no-op if the job has already completed. Composio generates an idempotency key when omitted and preserves it for retries within this execution. Reuse a caller-supplied key for the same cancellation across separate calls. |
| `MAILFLOSS_CHECK_API_KEY` | Check API Key | Verify that the connected Mailfloss API key is valid. Uses the connection's Bearer credential and does not accept credentials, request widget tokens, or return signed-proof fields. |
| `MAILFLOSS_CREATE_BATCH_VERIFICATION` | Create Batch Verification | Submit email addresses for asynchronous batch verification and return the job ID. Optionally request a completion webhook instead of polling. This billable action can fail with 402 insufficient_credits. Composio generates an idempotency key when none is supplied, so internal retries reuse the same key and email list. Separate action calls replay the cached response only when the caller reuses that key with identical emails; changing the list fails with 422, while a concurrent same-key request can fail with 409. |
| `MAILFLOSS_ERASE_VERIFICATION_RECORDS` | Erase Verification Records | Permanently erase stored verification records for the supplied email addresses. This destructive data-privacy operation is irreversible; erased records cannot be recovered. Addresses with no stored records are a successful no-op. The body contains only the documented emails array. Composio generates an idempotency key when omitted and preserves it for retries within this execution. |
| `MAILFLOSS_GET_ACCOUNT` | Get Account | Return the authenticated Mailfloss account holder's identity, contact details, security posture, notification preferences, and signup time. This read does not expose API credentials or two-factor secrets. |
| `MAILFLOSS_GET_BATCH_VERIFICATION_RESULTS` | Get Batch Verification Results | Return one cursor-controlled page of stored batch results after organization floss-setting overrides. These statuses and reasons can differ from Verify Email's raw verdict for the same address; fetching stored results is not documented as consuming verification credits. |
| `MAILFLOSS_GET_BATCH_VERIFICATION_STATUS` | Get Batch Verification Status | Read an asynchronous batch verification job's state and available counters. Polling is not documented as consuming verification credits; authentication, policy, not-found, rate-limit, and server responses remain errors rather than job states. |
| `MAILFLOSS_GET_JOB` | Get Verification Job | Return one verification job and its complete verdict breakdown. Results are null until completion and include all per-reason counters when present. |
| `MAILFLOSS_GET_ORGANIZATION` | Get Organization | Return the authenticated Mailfloss organization's plan, credit balances, current-period usage, trial state, account status, and feature entitlements. This is a read-only view and does not expose API or billing credentials. |
| `MAILFLOSS_GET_USAGE_REPORT` | Get Usage Report | Return verification usage for a UTC calendar period, optionally scoped to one ESP connection. Lifetime reports contain only the authoritative total; their range, status counts, and reason counts are null. |
| `MAILFLOSS_LIST_JOBS` | List Verification Jobs | Return one page of the organization's verification-job history, newest first, with optional source and lifecycle filters. Completed jobs include verdict totals; use Get Job for the full per-reason breakdown. |
| `MAILFLOSS_VERIFY_EMAIL` | Verify Email | Verify one email address and return Mailfloss's raw engine verdict without organization floss-setting overrides. passed means safe to send, undeliverable is a hard failure, risky covers role, disposable, bounced, or complained addresses, and unknown includes accept-all addresses and transient SMTP failures. relay and gibberish are annotations and do not alter the verdict. Each successful call consumes one verification credit; a depleted balance fails with 402 insufficient_credits, so do not retry billable failures blindly. |

## 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 mailfloss from Atomic Agent
With your account connected, ask Atomic Agent to work with mailfloss 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 mailfloss MCP Agent with another framework

- [ChatGPT](https://composio.dev/toolkits/mailfloss/framework/chatgpt)
- [Claude Cowork](https://composio.dev/toolkits/mailfloss/framework/claude-cowork)
- [Hermes](https://composio.dev/toolkits/mailfloss/framework/hermes-agent)

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## Frequently Asked Questions

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

With a standalone mailfloss MCP server, the agents and LLMs can only access a fixed set of mailfloss tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from mailfloss 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 mailfloss tools.

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

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

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