brainjar

Shape how your AI thinks — soul, persona, rules.

brainjar manages AI agent behavior through composable layers. Instead of one monolithic config file, you separate what the agent sounds like (soul), how it works (persona), and what constraints it follows (rules). Each layer is a markdown file. Mix, match, and switch them per project, per task, or per session.

Documentation · Getting Started

Quick start

# Install
bun install -g @brainjar/cli

# Initialize with starter content
brainjar init --default

# See what's active
brainjar status

Concepts

| Layer | Purpose | |-------|---------| | Soul | Who the agent is — voice, character, standards | | Persona | How the agent works — role, workflow, bundled rules | | Rules | Behavioral constraints — guardrails that apply regardless of persona | | Brain | Saved snapshot of soul + persona + rules — activate in one shot |

Commands

brainjar init [--default] [--backend claude|codex]
brainjar status [--sync] [--workspace] [--project] [--short]
brainjar sync [--quiet]
brainjar compose <brain> [--persona <name>] [--task <text>]

brainjar brain save|use|list|show|drop
brainjar soul create|use|show|list|drop
brainjar persona create|use|show|list|drop
brainjar rules create|add|remove|show|list

brainjar pack export|import
brainjar hooks install|remove|status [--local]
brainjar shell [--brain <name>] [--soul <name>] [--persona <name>]
brainjar reset [--backend claude|codex]
brainjar server start|stop|status|logs|local|remote
brainjar upgrade [--cli-only] [--server-only]
brainjar migrate [--dry-run] [--skip-backup]

See the CLI reference for full details.

Development

Built with Bun and incur.

bun install
bun test
bun run src/cli.ts --help