How to integrate Customjs MCP with Atomic Agent

Connect Atomic Agent to Customjs MCP. Convert this html invoice to pdf file, take a screenshot of your company homepage, and more using natural language, with authentication handled for you.

Customjs logoCustomjs
Api Key

Customjs is a code-first automation platform for integrating custom JavaScript logic across your tech stack. It lets you extend applications quickly by writing functions for tasks like emails, PDFs, or CRM updates.

5 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 Customjs.

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

Also integrate Customjs with

How Atomic Agent connects to Customjs

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

The Customjs MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Customjs account. It provides structured and secure access to your Customjs automations, so your agent can convert HTML to PDFs and images, capture website screenshots, merge PDF files, and run custom browser scripts on your behalf.

  • HTML to PDF and PNG conversion: Instantly generate high-quality PDFs or PNG images from any HTML markup or template using agent commands.
  • Automated webpage screenshot capture: Have your agent take precise, up-to-date screenshots of any public webpage for documentation, monitoring, or reporting.
  • PDF merging and file handling: Let your agent combine multiple PDF files into a single document, perfect for reports or document consolidation tasks.
  • Headless browser automation with Puppeteer: Empower your agent to execute custom Puppeteer scripts—scraping data or capturing advanced browser screenshots as PNGs.
  • Secure API key authentication: Ensure that all actions are performed securely by verifying your Customjs API key through the agent-managed authentication flow.

Use Customjs from Atomic Agent

With your account connected, ask Atomic Agent to work with Customjs 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 Customjs action and event your agent gets out of the box.

Authenticate CustomJS API Key

Authenticate and validate a CustomJS API key.

Convert HTML to PDF

Convert HTML content to a PDF document.

Convert HTML to PNG

Tool to convert HTML string to PNG image.

Merge multiple PDFs into one

Merge multiple PDF files from URLs into a single PDF document.

Run Puppeteer Script

Execute a Puppeteer script in a headless browser and capture a screenshot.

FAQ

Frequently asked questions

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

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

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