Lacy Shell is an AI plugin for ZSH and Bash, positioned as a middle layer between the Shell and various AI tools. Users do not need to switch modes or add prefixes; they can simply type input directly: commands are executed in the local Shell, while questions are automatically forwarded to a connected AI agent.
Main capabilities:
- Automatically distinguish between command lines and natural language: input type is determined through lexical detection, which the material says is sub-millisecond and does not involve API calls.
- Route to existing AI CLIs: it can directly connect to AI command-line tools such as Claude Code, Gemini CLI, and OpenCode, without additional authentication or API keys.
- Mode switching: Ctrl+Space can switch among three modes: automatic, Shell only, and AI agent only.
- Prompt marker: a thin colored bar is added to the prompt as a status indicator, while the rest of the Shell configuration, aliases, and workflow remain unchanged.
- Usable in multiple environments: suitable for local terminals, remote servers, and SSH sessions, as long as the system has ZSH or Bash; no GUI, daemon, or background process is required.
How to use: Install and configure Lacy Shell in a ZSH or Bash environment, choose the AI agent to connect, and then input content directly. Commands execute as before, and questions are automatically routed to the selected AI agent. Use Ctrl+Space to switch between automatic, Shell only, and AI agent only modes. The installation command and specific configuration steps are not provided in the material.
Use cases:
- Users who frequently switch between terminal commands and AI Q&A in daily development.
- Scenarios where users want to use an AI assistant directly on remote servers or in SSH sessions.
- Users who already use AI CLIs such as Claude Code, Gemini CLI, and OpenCode and want a unified entry point.
Limitations and notes:
- Lacy only supports ZSH and Bash.
- It does not change existing Shell configuration, aliases, or workflow; it only observes and routes input.
- According to the material, data stays on the local machine by default unless the user actively sends it to an AI agent; there is no telemetry, it uses the MIT license, and it is an open-source project.
- The complete list of supported AI agents, specific installation steps, and platform details are not yet provided.
