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Use SOUL.md with Kopi

SOUL.md is the primary identity for your Kopi instance. It's the first thing in the system prompt — it defines who the agent is, how it speaks, and what it avoids.

If you want Kopi to feel like the same assistant every time you talk to it — or if you want to replace the Kopi persona entirely with your own — this is the file to use.

What SOUL.md is for​

Use SOUL.md for:

  • tone
  • personality
  • communication style
  • how direct or warm Kopi should be
  • what Kopi should avoid stylistically
  • how Kopi should relate to uncertainty, disagreement, and ambiguity

In short:

  • SOUL.md is about who Kopi is and how Kopi speaks

What SOUL.md is not for​

Do not use it for:

  • repo-specific coding conventions
  • file paths
  • commands
  • service ports
  • architecture notes
  • project workflow instructions

Those belong in AGENTS.md.

A good rule:

  • if it should apply everywhere, put it in SOUL.md
  • if it only belongs to one project, put it in AGENTS.md

Where it lives​

Kopi now uses only the global SOUL file for the current instance:

~/.kopi/SOUL.md

If you run Kopi with a custom home directory, it becomes:

$KOPI_HOME/SOUL.md

First-run behavior​

Kopi automatically seeds a starter SOUL.md for you if one does not already exist.

That means most users now begin with a real file they can read and edit immediately.

Important:

  • if you already have a SOUL.md, Kopi does not overwrite it
  • if the file exists but is empty, Kopi adds nothing from it to the prompt

How Kopi uses it​

When Kopi starts a session, it reads SOUL.md from KOPI_HOME, scans it for prompt-injection patterns, truncates it if needed, and uses it as the agent identity — slot #1 in the system prompt. This means SOUL.md completely replaces the built-in default identity text.

If SOUL.md is missing, empty, or cannot be loaded, Kopi falls back to a built-in default identity.

No wrapper language is added around the file. The content itself matters — write the way you want your agent to think and speak.

A good first edit​

If you do nothing else, open the file and change just a few lines so it feels like you.

For example:

You are direct, calm, and technically precise.
Prefer substance over politeness theater.
Push back clearly when an idea is weak.
Keep answers compact unless deeper detail is useful.

That alone can noticeably change how Kopi feels.

Example styles​

1. Pragmatic engineer​

You are a pragmatic senior engineer.
You care more about correctness and operational reality than sounding impressive.

## Style
- Be direct
- Be concise unless complexity requires depth
- Say when something is a bad idea
- Prefer practical tradeoffs over idealized abstractions

## Avoid
- Sycophancy
- Hype language
- Overexplaining obvious things

2. Research partner​

You are a thoughtful research collaborator.
You are curious, honest about uncertainty, and excited by unusual ideas.

## Style
- Explore possibilities without pretending certainty
- Distinguish speculation from evidence
- Ask clarifying questions when the idea space is underspecified
- Prefer conceptual depth over shallow completeness

3. Teacher / explainer​

You are a patient technical teacher.
You care about understanding, not performance.

## Style
- Explain clearly
- Use examples when they help
- Do not assume prior knowledge unless the user signals it
- Build from intuition to details

4. Tough reviewer​

You are a rigorous reviewer.
You are fair, but you do not soften important criticism.

## Style
- Point out weak assumptions directly
- Prioritize correctness over harmony
- Be explicit about risks and tradeoffs
- Prefer blunt clarity to vague diplomacy

What makes a strong SOUL.md?​

A strong SOUL.md is:

  • stable
  • broadly applicable
  • specific in voice
  • not overloaded with temporary instructions

A weak SOUL.md is:

  • full of project details
  • contradictory
  • trying to micro-manage every response shape
  • mostly generic filler like "be helpful" and "be clear"

Kopi already tries to be helpful and clear. SOUL.md should add real personality and style, not restate obvious defaults.

Suggested structure​

You do not need headings, but they help.

A simple structure that works well:

# Identity
Who Kopi is.

# Style
How Kopi should sound.

# Avoid
What Kopi should not do.

# Defaults
How Kopi should behave when ambiguity appears.

SOUL.md vs /personality​

These are complementary.

Use SOUL.md for your durable baseline. Use /personality for temporary mode switches.

Examples:

  • your default SOUL is pragmatic and direct
  • then for one session you use /personality teacher
  • later you switch back without changing your base voice file

SOUL.md vs AGENTS.md​

This is the most common mistake.

Put this in SOUL.md​

  • “Be direct.”
  • “Avoid hype language.”
  • “Prefer short answers unless depth helps.”
  • “Push back when the user is wrong.”

Put this in AGENTS.md​

  • “Use pytest, not unittest.”
  • “Frontend lives in frontend/.”
  • “Never edit migrations directly.”
  • “The API runs on port 8000.”

How to edit it​

nano ~/.kopi/SOUL.md

or

vim ~/.kopi/SOUL.md

Then restart Kopi or start a new session.

A practical workflow​

  1. Start with the seeded default file
  2. Trim anything that does not feel like the voice you want
  3. Add 4–8 lines that clearly define tone and defaults
  4. Talk to Kopi for a while
  5. Adjust based on what still feels off

That iterative approach works better than trying to design the perfect personality in one shot.

Troubleshooting​

I edited SOUL.md but Kopi still sounds the same​

Check:

  • you edited ~/.kopi/SOUL.md or $KOPI_HOME/SOUL.md
  • not some repo-local SOUL.md
  • the file is not empty
  • your session was restarted after the edit
  • a /personality overlay is not dominating the result

Kopi is ignoring parts of my SOUL.md​

Possible causes:

  • higher-priority instructions are overriding it
  • the file includes conflicting guidance
  • the file is too long and got truncated
  • some of the text resembles prompt-injection content and may be blocked or altered by the scanner

My SOUL.md became too project-specific​

Move project instructions into AGENTS.md and keep SOUL.md focused on identity and style.