How to connect Postmark 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 Postmark account to Cowork via Composio Connect, enabling it to send a password reset email to user, get delivery status for last 10 emails, list all bounced emails from today, and more such actions on your behalf without compromising your account security.

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Postmark

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Postmark is an email delivery service for sending transactional emails with reliable deliverability. It delivers detailed analytics and fast, secure email delivery for developers.

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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 Postmark account to Cowork via Composio Connect, enabling it to send a password reset email to user, get delivery status for last 10 emails, list all bounced emails from today, and more such actions on your behalf without compromising your account security.

Also integrate Postmark with

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

Connecting Postmark 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 Postmark account

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

For example, ask Cowork to:

"Send a password reset email to user"
"Get delivery status for last 10 emails"
"List all bounced emails from today"

It will prompt you to authenticate and authorize access.

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

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

The Postmark MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Postmark account. It provides structured and secure access to transactional email sending and analytics, so your agent can perform actions like delivering transactional emails, monitoring delivery status, managing templates, and analyzing engagement metrics on your behalf.

Automated transactional email delivery: Let your agent send password resets, confirmations, and notification emails with high deliverability and reliability.
Template management and customization: Enable your agent to create, update, or select dynamic email templates for consistent, branded communications.
Email delivery status monitoring: Ask your agent to track sent messages, check delivery receipts, and identify bounced or failed emails in real time.
Engagement and analytics tracking: Have your agent retrieve open and click data, analyze engagement trends, and provide actionable insights from your email campaigns.
Suppression list and recipient management: Direct your agent to manage suppression lists, process unsubscribes, and maintain healthy recipient lists automatically.

TOOLS

Supported Tools

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

Archive Message Stream

Tool to archive a message stream (soft delete).

Check Spam Score

Tool to assess the spam score of a raw email via the SpamCheck API.

Create Inbound Rule

Tool to create a new inbound rule trigger to block email from a specific sender or domain.

Create Message Stream

Tool to create a new message stream.

Create Suppressions

Tool to add email addresses to the suppression list for a message stream.

Create Template

Tool to create a new email template.

Create Webhook

Tool to create a new webhook configuration for Postmark.

Delete Inbound Rule

Tool to delete a specific inbound rule trigger.

Delete Suppressions

Tool to remove email addresses from the suppression list for a message stream.

Delete Template

Tool to delete a template by its ID or alias.

Delete Webhook

Tool to delete a specific webhook.

Edit Server

Tool to update settings for the current Postmark server.

Edit Template

Tool to update an existing Postmark template by its ID.

Edit Webhook

Tool to update an existing webhook’s URL or triggers.

Get Bounce Counts

Tool to get total counts of emails that have been returned as bounced.

Get Bounces

Tool to retrieve a list of bounces for a server with optional filters.

Get Browser Platform Usage

Tool to retrieve browser platform usage statistics for clicked links.

Get Browser Usage

Tool to retrieve browser usage statistics for clicked links.

Get Click Counts

Tool to retrieve total click counts across all links in emails.

Get Clicks By Browser Family

Tool to retrieve click statistics grouped by browser family.

Get Clicks by Location

Tool to get an overview of which part of the email links were clicked from (HTML or Text).

Get Delivery Stats

Tool to retrieve delivery statistics.

Get Email Client Usage

Tool to retrieve statistics on email clients used to open emails.

Get Email Open Counts

Tool to retrieve counts of opened emails.

Get Message Stream

Tool to retrieve details of a specific message stream by its ID.

Get Opens by Platform

Tool to retrieve email open statistics by platform type.

Get Outbound Overview

Tool to retrieve outbound email statistics overview.

Get Sent Counts

Tool to retrieve total count of emails sent out.

Get Server

Tool to retrieve details of the current Postmark server.

Get Spam Complaints

Tool to retrieve counts of spam complaints.

Get Template

Tool to retrieve details of a specific template by its ID.

Get Tracked Email Counts

Tool to retrieve counts of emails with tracking enabled.

Get Webhook

Tool to retrieve details of a specific webhook by its ID.

List Inbound Rules

Tool to list all inbound rules (triggers) configured for blocking senders.

List Message Streams

Tool to list all message streams for a Postmark server with optional type and archive filtering.

List Outbound Message Clicks

Tool to list clicks for outbound messages with filtering options.

List Outbound Message Opens

Tool to retrieve opens for outbound messages with filtering options.

List Suppressions

Tool to retrieve the suppression list for a message stream with optional filtering.

List Templates

Tool to list all templates for a Postmark server.

List Webhooks

Tool to list all webhooks configured for your Postmark account.

Search Inbound Messages

Tool to search inbound messages received with optional filtering.

Search Outbound Messages

Tool to search outbound messages with filtering by recipient, tag, status, and date range.

Send Batch Templated Emails

Tool to send multiple templated emails in a single batch API call.

Unarchive Message Stream

Tool to unarchive a previously archived message stream.

Update Message Stream

Tool to update a message stream configuration in Postmark.

Validate Template

Tool to validate a Postmark template.

FRAMEWORKS

How to build Postmark MCP Agent with another framework

OpenAI Agents SDK

Use Postmark MCP with OpenAI Agents SDK

Claude Agent SDK

Use Postmark MCP with Claude Agent SDK

Claude Code

Use Postmark MCP with Claude Code

Codex

Use Postmark MCP with Codex

OpenClaw

Use Postmark MCP with OpenClaw

Hermes

Use Postmark MCP with Hermes

CLI

Use Postmark MCP with CLI

Google ADK

Use Postmark MCP with Google ADK

LangChain

Use Postmark MCP with LangChain

Vercel AI SDK

Use Postmark MCP with Vercel AI SDK

Mastra AI

Use Postmark MCP with Mastra AI

LlamaIndex

Use Postmark MCP with LlamaIndex

CrewAI

Use Postmark MCP with CrewAI

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FAQ

Frequently asked questions

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

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

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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