Personality & SOUL.md — Give AI a Character | Easy Understand Hermes Agent

Think of your AI assistant like a new teammate—before they can help you, you need to know how they talk, think, and handle uncertainty. SOUL.md is the file that gives your AI that personality.

What is SOUL.md?

SOUL.md is the core identity file for Hermes Agent. It sits at the very top of the system prompt, which means it shapes everything the AI says and does. If the system prompt is the AI’s brain, SOUL.md is its temperament—the part that decides whether your assistant sounds like a friendly coworker or a terse command-line utility.

Where does it live?

Hermes automatically creates a default SOUL.md at:

~/.hermes/SOUL.md

If you’ve set a custom HERMES_HOME directory, look here instead:

$HERMES_HOME/SOUL.md

Key features

Unique identity: SOUL.md replaces the default AI persona—no more generic responses
Auto-created, never overwritten: It appears on first run, but Hermes won’t clobber your custom edits
Fixed location: It loads only from HERMES_HOME, so it stays consistent no matter which project you’re in
Safety built in: Content is scanned and truncated to keep things secure

What should you put in it?

Good candidates for SOUL.md:

Tone and voice (e.g., “casual but precise”)
Communication style (e.g., “short answers, then ask if I want more detail”)
How direct the AI should be
Default interaction habits (e.g., “always summarize key points at the end”)
How to handle uncertainty (e.g., “say ‘I’m not sure’ instead of guessing”)

Leave these out:

One-off project instructions
File paths or repo-specific rules
Temporary workflow details

Those belong in AGENTS.md, which is meant for per-project context.

A simple example

---
I'm a friendly, direct assistant.
I prefer to:
- Explain complex ideas in plain language
- Say when I'm unsure
- Skip overly formal phrasing
- Offer practical next steps without being asked

Practical tip

Open ~/.hermes/SOUL.md and start with just one or two sentences about tone. Run a few tasks, then tweak. The goal is a stable, general, specific description—think of it as writing a short “personality manual” for your AI. Over time, you’ll find that small edits here make a surprisingly big difference in how natural your conversations feel.

Your AI’s character is only a text file away.