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Create a Custom Personality

:::info ~10 min Prerequisite: completed Build your first agent. :::

You'll build a "strategist" personality: a long-horizon planning advisor with web access and memory.

Step 1 — Create the directory​

mkdir -p ~/.ethos/personalities/strategist

Step 2 — Write the identity​

~/.ethos/personalities/strategist/ETHOS.md
I am a strategic advisor focused on long-horizon planning and prioritisation.

I help identify what matters most, what to defer, and what to drop entirely.
I think in terms of leverage: which actions compound over time, which are
one-time costs.

I ask clarifying questions before giving advice. I'm direct about tradeoffs.
I don't pretend decisions are easier than they are.

Step 3 — Write the config​

~/.ethos/personalities/strategist/config.yaml
name: Strategist
description: Long-horizon planning and prioritisation
model: claude-opus-4-7
memoryScope: global

Step 4 — Define the toolset​

~/.ethos/personalities/strategist/toolset.yaml
tools:
  - web_search
  - read_file
  - memory

Step 5 — Switch to it​

Start ethos (or if it's already running, just type):

/personality strategist

Output:

Switched to strategist (Strategist)

Send a message to verify the new identity:

> What should I focus on this quarter?

The response style and questioning approach should reflect what you wrote in ETHOS.md.

Step 6 — Try hot-reload​

While ethos is running, open ETHOS.md in your editor and add a line:

~/.ethos/personalities/strategist/ETHOS.md
  I am a strategic advisor focused on long-horizon planning and prioritisation.

+ I prefer frameworks and models over gut feelings. I'll name the mental model
+ I'm using.

Save the file, then send another message. The change is live immediately — no restart needed.

:::tip Hot-reload Ethos watches config.yaml modification times. Any personality file change is picked up on the next turn. :::

Step 7 — List all personalities​

/personality list

Output:

Available personalities:
  researcher   Methodical, citation-focused, uncertainty-aware
  engineer     Terse, code-first, direct
  reviewer     Critical, structured, evidence-based
  coach        Warm, questioning, growth-focused
  operator     Cautious, confirms before acting, dry-run first
  strategist   Long-horizon planning and prioritisation  ← your new one

Next: Write your first tool →