PERSONA.md
The open spec for AI Personas.
Every AI agent in production runs on a behavioral specification. Until now, that specification lived in system prompts — unversioned, locked to one platform, invisible to compliance. PERSONA.md is the open standard that changes that: a declarative format that captures all nine dimensions of who an agent is, portable across every model, versionable like any other piece of infrastructure, and auditable when regulators ask.
What it is
The behavioral layer is the most critical part of any AI system. It has never had a proper standard. Until now.
PERSONA.md is a declarative spec — YAML frontmatter and Markdown — that captures nine dimensions of an AI Persona in a single artifact: identity, character, personality, cognition, affect, drives, constraints, memory, and the mask it presents to the world. It is the source of truth for who your agent is. The CLI compiles it to the native format of any tool your team uses — Claude Code, OpenClaw, Cursor, or custom JSON. Change models. Change frameworks. The spec stays.
MIT licensed. Published on GitHub. The standard belongs to the community — Personaxis builds the tooling and platform around it.
Nine dimensions
Each maps to a field in the spec. Together they define an AI Persona completely.
identity:
Identity
character:
Character
personality:
Personality
cognition:
Cognition
affect:
Affect
drives:
Drives
constraints:
Constraints
memory:
Memory
persona:
Persona
How it works
01
Write
Run personaxis init and fill in your AI Persona's nine dimensions.
02
Validate
The CLI checks your spec against the schema and flags missing or contradictory fields.
03
Compile
Generate SOUL.md for OpenClaw, rules for Cursor, system prompts for Claude — from one source.
04
Publish
Push to the registry. Version it, share it with your team, or keep it private.
Fits your stack
PERSONA.md completes the triangle — it does not replace the standards you already use.
AGENTS.md
What your agent does in the repo
SKILL.md
What your agent can do
PERSONA.md
Who your agent is
Why we built it.
Five beliefs about AI agents, character drift, and why the spec was missing.