# The Postmark MCP server, one year later: from 4 tools to 24

DevFeed: [The Postmark MCP server, one year later: from 4 tools to 24](<https://devfeed.tech/articles/the-postmark-mcp-server-one-year-later-from-4-tools-to-24-16086.md>)

Original publisher: [Read original article](<https://postmarkapp.com/blog/the-postmark-mcp-server-one-year-later-from-4-tools-to-24>)

Author: Jabal Torres (jtorres@activecampaign.com)

Published: 2026-07-21T16:05:00Z

Content type: opinion

Language: en

Sources: [Postmark (en-US)](<https://devfeed.tech/sources/postmark-en-us.md>)

Topics: [MCP](<https://devfeed.tech/topics/mcp.md>), [MCP Server](<https://devfeed.tech/topics/mcp-server.md>), [API](<https://devfeed.tech/topics/api.md>), [AI Agent](<https://devfeed.tech/topics/ai-agent.md>)

Tags: [ai-agent](<https://devfeed.tech/tags/ai-agent.md>), [api](<https://devfeed.tech/tags/api.md>), [diagnostics](<https://devfeed.tech/tags/diagnostics.md>), [mcp](<https://devfeed.tech/tags/mcp.md>), [mcp-server](<https://devfeed.tech/tags/mcp-server.md>), [product-news](<https://devfeed.tech/tags/product-news.md>), [tool](<https://devfeed.tech/tags/tool.md>)

## AI overview

Postmark reflects on a year of developing and operating its MCP server, which grew from four tools to 24 in the official @activecampaign/postmark-mcp package. The article explains why designing tools around user outcomes, such as the diagnoseDelivery workflow, is different from mechanically wrapping API endpoints.

## Source excerpt

About a year ago, we introduced something experimental from Postmark Labs: an MCP server that let an AI assistant send email through Postmark. It shipped with exactly one useful tool, sendEmail, plus three supporting ones (four total). You gave it a recipient, a subject, and a body, and it sent. We said at the time we'd started with a single Postmark server "because we had to start somewhere." A lot has happened since. The project graduated from Labs and became the official @activecampaign/postmark-mcp package, and along the way, we learned a lot about what it actually takes to put an AI assistant in front of a production email API responsibly. The latest release, v2.1.1, ships 24 tools across eight categories: sending, templates, message search, delivery diagnostics, bounces, suppressions, stats, and webhooks. But the tool count isn't really the story. The story is what a year of running this thing taught us: designing tools for an AI agent is a different discipline than wrapping an API, and once your server has an official name, everything downstream of that name needs to earn it. From one endpoint to a whole surface The original four tools mirrored individual Postmark endpoints directly. Getting from there to 24 the naive way -- one tool per endpoint, mechanically -- is where we started. But somewhere around tool ten, we realized that users interacting with an AI assistant don't conceptualize their needs as API calls. They approach it with human inquiries. That reframing shaped everything that mattered about the v2.0 release. Designing for outcomes, not endpoints The best example of that shift doesn't map to a single Postmark endpoint at all. It's called diagnoseDelivery, and it exists to answer one very human question: did my email actually reach this person, and if not, why? Before, answering that meant a five-step investigation across the dashboard: search outbound messages, pull the message details, read the event timeline, check the suppression list, check the