v0.4 — Open Standard

SoulSpec
The Open Standard for
AI Agent Personas

A structured, portable format for defining AI agent identity, personality, and behavior. Works with any SOUL.md-compatible agent framework.


What is SoulSpec?

A minimal set of files that give your AI agent a persistent, portable identity.

📋

soul.json

Package manifest. Metadata, compatibility, versioning, and discovery — the agent's passport.

🧠

SOUL.md

Core personality. Values, communication style, opinions, and behavioral guidelines.

🪪

IDENTITY.md

Who the agent is. Name, role, backstory, and contextual positioning.

⚙️

AGENTS.md

Operational workflow. Task handling, tool usage, memory patterns, and autonomous behaviors.

AGENTS.md defines how agents work on your code. SoulSpec defines who your agent is.


Why a Standard?

AI agents need identity. But everyone defines it differently — or not at all.

466
open-source AI agent projects analyzed — no standardized structure for persona definitions found.
"Analyzing SOUL.md and Structured Persona Files in Open-Source AI Agent Repositories" — MSR 2026 · arXiv:2510.21413
SoulSpec provides a shared vocabulary. Instead of ad-hoc system prompts scattered across configs, you get a structured, versionable, shareable format that any framework can consume.

The Spec

Simple file structure. Markdown + JSON. No build step, no runtime dependency.

my-agent/
├── soul.json      ← manifest (required)
├── SOUL.md       ← personality (required)
├── IDENTITY.md   ← who you are
├── AGENTS.md     ← workflows
├── STYLE.md      ← communication style
├── HEARTBEAT.md  ← autonomous check-in
└── examples/
    ├── good-outputs.md
    └── bad-outputs.md
soul.json
{
  "specVersion": "0.4",
  "name": "my-agent",
  "displayName": "My Agent",
  "version": "1.0.0",
  "description": "A helpful agent with strong opinions.",
  "license": "MIT",
  "tags": ["general", "opinionated"],
  "compatibility": {
    "frameworks": ["openclaw", "cursor", "windsurf"]
  },
  "files": {
    "soul": "SOUL.md",
    "identity": "IDENTITY.md",
    "agents": "AGENTS.md"
  }
}

Ecosystem

SoulSpec works with any framework that reads SOUL.md. These already do.

🦞
OpenClaw
CLI Agent
🤖
Claude Code
CLI Agent
💬
Claude Desktop
Desktop App
👥
Claude Cowork
Team Agent
⌨️
Cursor
IDE Agent
🏄
Windsurf
IDE Agent
💎
ChatGPT
Chat App

Start Building

Create, discover, and verify agent personas.


Research

SoulSpec is grounded in empirical research on AI agent persona practices.

🔥 Origins — Peter Steinberger

The SOUL.md pattern was pioneered by Peter Steinberger, creator of OpenClaw. Inspired by Anthropic's constitutional AI work, he created soul.md and identity.md to give AI agents persistent personality — sparking an entire ecosystem.

Lex Fridman Podcast #491 →

💡 Software is Changing (Again) — Andrej Karpathy

Karpathy's landmark essay argues that LLMs create a new computing paradigm where natural-language prompts replace traditional code — making structured persona files the "source code" of AI agents.

Watch on YC →

📄 MSR 2026 — Mining Software Repositories

Analyzing SOUL.md and Structured Persona Files in Open-Source AI Agent Repositories. A large-scale empirical study of 466 OSS projects examining how developers define AI agent personas.

arXiv:2510.21413

📦 Zenodo Dataset

Replication package with full dataset, analysis scripts, and supplementary materials.

DOI: 10.5281/zenodo.18772585

Resources

Learn more about the SOUL.md ecosystem.