Soul Builder

Give your AI Agent a Soul.And launch it in the ChatGPT App Store.

The soul.md framework for agents with personality - plus the complete path from MCP server to your own ChatGPT App. Step by step, with full code.

soul.md Framework · Best Practices
MCP Server · ChatGPT App Store
10 Chapters · Full Code
The Idea

Every agent needs a soul. Not just a prompt.

Most AI agents sound the same - interchangeable, generic, soulless. A soul.md changes that: it defines the personality, values and voice of your agent in a structured file.

Name

Who are you?

Personality

How are you?

Core Values

What matters to you?

Tone

How do you speak?

Backstory

Where do you come from?

Signature

What makes you recognisable?

Six questions. Five minutes. An agent with character.

This guide doesn't just show you how to create a soul.md - it shows you how to ship the agent as a real ChatGPT App to the App Store.

What's inside

From framework to finished app. Everything in one guide.

soul.md Framework & Best Practices

Learn how to give your agent a unique personality - structured and repeatable.

Build an MCP Server from scratch

Complete, annotated TypeScript code with integrated soul.md - no boilerplate guesswork.

Deploy and submit

From Render.com hosting to ChatGPT App Store submission - the complete process, documented.

Monetisation & Next Steps

Freemium models, API keys, premium features - how to make money with your app.

10 Chapters

The complete roadmap.

From soul.md to finished app in the ChatGPT Store - documented over a single Saturday morning.

00

Why agents need a soul

The idea behind soul.md, why personality makes the difference, and what you can do after this guide.

01

The SOUL.md Framework

Name, Personality, Core Values, Tone, Backstory, Signature - how to define your agent's identity.

02

What is a ChatGPT App?

MCP vs. old plugins, OpenAI's app ecosystem, and why MCP is the future standard.

03

Tech Stack & Tools

Node.js, TypeScript, Express, MCP SDK - why this stack and how to set everything up.

04

Building the MCP Server

Step by step to a working server - with complete, annotated code and integrated soul.md.

05

Hosting on Render.com

From GitHub repo to live server. Free tier, auto-deploy, health checks.

06

ChatGPT App Submission

Domain verification, tool annotations, test cases, screenshots - the complete process.

07

After Submission

What happens in review? Common rejection reasons and how to fix them.

08

Monetisation & Next Steps

Freemium, API keys, premium features - how to earn money with your app.

09

Template + Checklist

Copy-paste-ready template for your own MCP server plus launch checklist incl. soul.md template.

A

Appendix

Complete code + soul.md template + launch checklist + glossary

Free Preview

Chapter 0: Why agents need a soul

The idea behind ag3nt.id

I build AI agents. Not as a hobby, not as a side project - as a business. Under the name ag3nt.id I help companies and individuals build AI agents that are more than a wrapper around an API. Agents that have an identity. A voice. A character.

That sounds abstract at first. But it isn't.

Imagine you build a customer service bot. You give it a system prompt, some tools, maybe a knowledge base. Technically it works. But when a customer talks to this bot, they immediately sense: this is a tool. Not a conversation partner. No personality. No recognisable brand.

Now imagine this bot has a name. Has three adjectives describing its personality. Has core values it uses to guide its responses. Has a communication style - relaxed-professional rather than corporate-sterile. Maybe even a backstory: "Born in a Berlin agency, trained on real customer conversations."

That is the difference between a tool and an agent. And exactly that difference is made by a SOUL.md - a structured personality file that defines everything that makes an agent unique.

Why agents need a soul

The AI industry has a problem: everything sounds the same. Every chatbot replies with "I'd be happy to help!" and "That's a great question!". Every agent is interchangeable because nobody takes the time to give it an identity.

A SOUL.md solves this. It's not a magic document - it's a structured configuration file for an agent's personality. Like a character sheet in a role-playing game, but for AI.

The idea is simple:

  • Name - Who are you?
  • Personality - How are you?
  • Core Values - What matters to you?
  • Tone - How do you speak?
  • Backstory - Where do you come from?
  • Signature - What makes you recognisable?

Six questions. Five minutes. And your agent has a soul.

Get started

Unlock Soul Builder

The soul.md framework, 10 chapters, complete code, templates - everything you need to launch your soulful agent as a ChatGPT App.

€29

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About the Author
MW

Markus Wolff

ag3nt.id · Soul Builder

Markus builds AI agents with personality. Under ag3nt.id he helps companies and individuals develop agents that are more than a wrapper around an API - agents with identity, voice and character.

This guide documents his own journey: from the soul.md framework through the MCP server to the finished app in the ChatGPT App Store - on a single Saturday morning.

FAQ

Frequently Asked Questions

What is a soul.md?

What do I need technically?

Does it work without TypeScript knowledge?

What if OpenAI rejects the app?

Are there updates?

Ready to give your agent a soul?

© 2026 Markus Wolff · ag3nt.id