How to connect Customjs 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 Customjs account to Cowork via Composio Connect, enabling it to convert this HTML invoice to PDF file, take a screenshot of your company homepage, merge these three PDF reports into one, and more such actions on your behalf without compromising your account security.

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Customjs

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

Managed auth

Connect Customjs without auth hassles

We manage OAuth, API keys, token refresh, and scopes — you just build.

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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 Customjs account to Cowork via Composio Connect, enabling it to convert this HTML invoice to PDF file, take a screenshot of your company homepage, merge these three PDF reports into one, and more such actions on your behalf without compromising your account security.

Also integrate Customjs with

OpenAI Agents SDK Claude Agent SDK Claude Code Codex OpenClaw Hermes CLI Google ADK LangChain Vercel AI SDK Mastra AI LlamaIndex CrewAI

Connecting Customjs 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 Customjs account

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

For example, ask Cowork to:

"Convert this HTML invoice to PDF file"
"Take a screenshot of your company homepage"
"Merge these three PDF reports into one"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Cowork, and your Customjs 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 Customjs through MCP without you sharing account credentials directly with the agent.

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.

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.

FRAMEWORKS

How to build Customjs MCP Agent with another framework

OpenAI Agents SDK

Use Customjs MCP with OpenAI Agents SDK

Claude Agent SDK

Use Customjs MCP with Claude Agent SDK

Claude Code

Use Customjs MCP with Claude Code

Codex

Use Customjs MCP with Codex

OpenClaw

Use Customjs MCP with OpenClaw

Hermes

Use Customjs MCP with Hermes

CLI

Use Customjs MCP with CLI

Google ADK

Use Customjs MCP with Google ADK

LangChain

Use Customjs MCP with LangChain

Vercel AI SDK

Use Customjs MCP with Vercel AI SDK

Mastra AI

Use Customjs MCP with Mastra AI

LlamaIndex

Use Customjs MCP with LlamaIndex

CrewAI

Use Customjs MCP with CrewAI

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Oauth2Api Key

Supabase is an open-source backend platform offering scalable Postgres databases, authentication, storage, and real-time APIs. It lets developers build modern apps without managing infrastructure.

Codeinterpreter

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Codeinterpreter is a Python-based coding environment with built-in data analysis and visualization. It lets you instantly run scripts, plot results, and prototype solutions inside supported platforms.

GitHub

Oauth2

GitHub is a code hosting platform for version control and collaborative software development. It streamlines project management, code review, and team workflows in one place.

Ably

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Ably is a real-time messaging platform for live chat and data sync in modern apps. It offers global scale and rock-solid reliability for seamless, instant experiences.

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. 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 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.

Start with Customjs.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Customjs tool your agent needs.Free to start.

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Customer stories

Teams ship real agents on Composio

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Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati

Co-founder, Slashy

A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

Abhi Arya

Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

Nirman Dave

CEO, Zams

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

Ryan Yu

Founder, Extra Thursday

Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

Tomisin Jenrola

Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Jerome Leclanche

Co-Founder, Ingram Technologies