How to integrate Docupost MCP with Atomic Agent

Connect Atomic Agent to Docupost MCP. Mail a pdf letter to your accountant, send a custom postcard to new customers, and more using natural language, with authentication handled for you.

Docupost logoDocupost
Api Key

Docupost is a print and mail service that lets you send digital files as physical letters or postcards via USPS. Instantly automate offline mailings without manual printing or trips to the post office.

3 Tools

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 Docupost.

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 Docupost account. See the Atomic Agent documentation for installation instructions.

Also integrate Docupost with

How Atomic Agent connects to Docupost

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 Docupost to Atomic Agent

  1. Sign up or sign in to the Composio dashboard. Copy your API key.
  2. 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.
  3. Ask Atomic Agent to do something in Docupost. It searches Composio for the right tool.
  4. On first use, open the sign-in link returned in the chat. Connect your Docupost 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 Docupost MCP server, and what's possible with it?

The Docupost MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Docupost account. It provides structured and secure access to Docupost's print and mail services, so your agent can send letters, mail postcards, and automate physical document delivery on your behalf.

  • Automated letter mailing: Direct your agent to send digital files as physical letters to any recipient in the U.S., specifying sender and recipient details.
  • Personalized postcard delivery: Have your agent create and mail custom postcards, using front and back image designs tailored for your recipients.
  • Bulk document distribution: Let your agent send batches of letters or postcards to multiple addresses, streamlining mass mail campaigns or notifications.
  • Seamless file-to-mail conversion: Enable your agent to instantly turn PDFs or images into tangible mail pieces, no printing or trips to the post office required.

Use Docupost from Atomic Agent

With your account connected, ask Atomic Agent to work with Docupost in natural language. You can connect more apps through the same Composio integration as you need them.

Visit the Atomic Agent website or inspect the Atomic Agent source code.

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 for the current limits that apply to your connection.

TOOLS

Supported Tools

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

Get Balance

Tool to check the current account balance in DocuPost.

Send Letter

Send a physical letter via U.

Send Postcard

Tool to send a postcard via U.

FAQ

Frequently asked questions

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

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 Docupost tools.

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

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