Lenos is a terminal AI coding assistant for the ttal ecosystem.

It runs agents in a real shell because bash is all you need. File edits happen through CLIs such as src; web lookup happens through web; skills are found and read through skill; project context comes from project; session goals are managed through goal. Lenos keeps the model-facing protocol small: Markdown for prose, <run> blocks for bash calls, and a built-in sandbox around execution.

That simplicity is the point. Compared with native tool-call protocols, the run protocol avoids provider-specific JSON schemas and typically cuts tool protocol tokens by 40%-60%. Stable prompt prefixes, compact runtime context, and the session journal make high cache hit rates easy; in daily use with DeepSeek V4 Pro, recent cache hit rates have been in the 98-99% range.

curl -fsSL https://github.com/tta-lab/lenos/releases/latest/download/install.sh | sh

The installer supports macOS and Linux on x86_64 and arm64. It installs Lenos to ~/.local/bin and also installs the Organon CLIs that Lenos prompts use: src, web, skill, project, and goal.

Linux sandboxing requires bubblewrap (bwrap). Install it with your distro package manager before running Lenos if it is not already present.

Add ~/.local/bin to your PATH if needed:

export PATH="$HOME/.local/bin:$PATH"

• Built-in sandbox: command execution is constrained by the Temenos sandbox SDK without a separate daemon.
• Simple run protocol: the model replies in Markdown and wraps shell work in <run> blocks. Lenos executes those blocks and feeds the real result back into the next turn.
• CLI-native tools: code editing, web lookup, skill discovery, project lookup, and goal management are regular shell commands, not hidden adapter APIs.
• High cache locality: runtime context is injected as stable command/result history instead of large changing prose blocks.
• Agent journal: task sessions maintain a journal the agent can read after compaction, preserving continuity without dragging full history forward.
• Background jobs: long-running shell commands can keep running while the session stays responsive, with job results fed back into the agent.
• Session storage: SQLite-backed sessions can be resumed, continued, compacted, and reviewed.
• Multi-provider models: Anthropic, OpenAI, Gemini, Bedrock, Copilot, Hyper, MiniMax, Vercel, DeepSeek-compatible routes, and other configured providers.
• Agent skills: local SKILL.md directories extend agent behavior without changing Lenos itself.
• ttal-native workflow: built for worker sessions, PR flow, and the wider ttal toolchain.

# Start the TUI in the current project.
lenos

# Run one prompt non-interactively.
lenos run "Summarize the current branch"

# Pipe content into a run.
git diff --cached | lenos run "Review this staged diff"

# Continue the most recent session.
lenos --continue

# Use a model for this session only.
lenos -m deepseek-v4-pro

# Use the configured small-tier model.
lenos --small-model

# Select the small tier and override its model for this session only.
lenos --small-model -m claude-haiku-3.5

# Persist preferred models.
lenos config set-model large deepseek-v4-pro
lenos config set-model small claude-haiku-3.5

CLI model flags are ephemeral. They do not write config.json and do not leak into future sessions. Use lenos config set-model when you want persistence.

Lenos reads configuration from these locations, highest priority first:

1. .lenos/config.json
2. $XDG_DATA_HOME/lenos/config.json or ~/.local/share/lenos/config.json
3. $XDG_CONFIG_HOME/lenos/config.json or ~/.config/lenos/config.json

See schema.json for all options and docs/hooks.md for lifecycle hooks.

Common environment variables:

Agent skills live in either global or project-local directories:

• ~/.config/lenos/skills/
• .lenos/skills/

Each skill is a directory with a SKILL.md file. The installer provides the skill CLI for finding and managing skill content.

Lenos links the Temenos sandbox SDK directly. The installer writes a starter Temenos config at ~/.config/temenos/config.toml and a starter Lenos config at ~/.lenos/config.json when those files do not already exist.

The old --yolo and permissions.allowed_tools paths are gone. Execution policy now belongs to the sandbox configuration and the runtime's tool rules.

make build
make test
make fmt
make lint-fix

Single-package tests use normal Go commands:

go test ./internal/agent -run TestName

Lenos is licensed under the Functional Source License, Version 1.1, MIT Future License.

Lenos is a fork of Crush by Charmbracelet, originally created by Kujtim Hoxha and the Charmbracelet team.

Major changes from upstream Crush include the github.com/tta-lab/lenos module path, the lenos binary name, .lenos data directories, LENOS_* environment variables, ttal runtime integration, sandboxed command execution, runtime context templates, session compaction, and the release installer above.

The FSL-1.1-MIT license terms are preserved. Original Charmbracelet and Kujtim Hoxha copyrights are retained in LICENSE.md.