ShowDEV: I built an AI-native shell in Rust because I was tired of Googling CLI errors

Source: Dev.to

Ever heard of J.A.R.V.I.S. from Marvel’s Iron Man? He is the highly intelligent, polite AI assistant that supports Tony Stark. I’ve always dreamed of building my very own J.A.R.V.I.S. to help me with my daily development.

But in reality, our daily workflow looks nothing like that. Have you ever run a command, gotten an obscure error, and had to copy‑paste the output into a browser or ChatGPT just to figure out what went wrong?

As developers, we do this multiple times a day. It completely breaks our flow state. I wanted to stop doing this. I wanted a true “J.A.R.V.I.S.”‑like experience—an assistant that lives inside my shell, already knows what just happened, and can help me instantly.

So, I built Jarvish.

🤵 Jarvis Shell (jarvish)

🌐 日本語版 README はこちら

💡 About

“I want J.A.R.V.I.S. as my companion — but inside my terminal.”

Jarvish is a next‑generation AI‑integrated shell written in Rust, inspired by J.A.R.V.I.S. from Marvel’s Iron Man. It natively embeds AI intelligence into your everyday shell experience—no more copy‑pasting errors into a browser. Just ask Jarvis.

✨ Features

🧠 AI‑Powered Assistance

• 💬 Talk to Jarvis in natural language—right from your shell prompt.
• 🔍 When a command fails, Jarvis automatically investigates the error using stdout/stderr context.
• 🛠️ Jarvis can read and write files, execute commands as an AI agent with tool‑calling capabilities.

🐟 Fish‑like UX

• 🎨 Real‑time syntax highlighting as you type.
• ⚡ Auto‑completion for commands (PATH binaries, builtins) and file paths.
• 📜 History‑based suggestions powered by reedline.

📦 The Black Box

• 🗃️ Every command execution is persisted—command, timestamp, working directory, exit status, and I/O.

🛠️ Why not just an AI CLI tool?

Existing tools like GitHub Copilot CLI are separate from the shell environment; you have to invoke them explicitly, and they lack context about the command you just ran.

Jarvish is different. It is a fully functional interactive shell.

• No mode switching: ls -la runs normally; Jarvis, why did my last build fail? is routed to the AI.
• The “Black Box” context: Jarvish silently captures all stdout/stderr, compresses it, and stores it in a local SQLite database. When you talk to the AI, it automatically retrieves recent I/O history as context.

🦀 Built with Rust

• reedline – provides the rich, Fish‑like REPL experience (syntax highlighting, autosuggestions).
• os_pipe – tees the output of child processes, capturing it for the AI while still rendering it to the terminal.
• async-openai – powers the agent loop; Jarvish uses function calling to autonomously read files, execute commands, and investigate issues.

🚀 Try it out!

Jarvish is currently at v1.0.1 and is used as a daily driver by its creator. It is open‑source—feel free to give it a spin.

cargo install jarvish

Enjoy a shell that talks back.