elelem-ratatui

Alpha. It works, with known gaps. Check the known issues before you rely on it.

elelem-ratatui is an early experiment: a full-screen terminal UI for elelem, written in Rust with ratatui. The screen has a log pane for replies, thinking, and tool calls, and an input box below it. It is basic, with no scrolling and minimal line editing, and it is not on RubyGems; build it from source.

Install #

You need Ruby 4.0, Bundler, and a Rust toolchain with cargo.

git clone https://git.mokhan.ca/elelem/ratatui.git
cd ratatui
bin/setup

bin/setup runs bundle install, then bundle exec rake compile. The compile task runs cargo build --release in rust/ and copies the binary to ext/elelem/ratatui/native/elelem-ratatui.

To install it as a gem instead, build the gem from the clone. gem install runs the same Rust build:

gem build elelem-ratatui.gemspec
gem install ./elelem-ratatui-0.1.0.gem

Use #

From the clone:

bin/run chat -p ollama

Installed as a gem:

elelem-ratatui chat -p anthropic

elelem-ratatui takes the same commands and options as elelem (chat, ask, files, -p, --model, --system-prompt) and loads elelem-builtins if it is installed. The difference is the screen.

The input box title shows the pending prompt, including permission questions from tools. The log pane’s title reads elelem (waiting…) while a request to the model is in flight.

How it works #

Loading elelem/ratatui replaces elelem’s input and output with 2 small Ruby classes. When the session is built, they start the Rust binary and keep it running until elelem exits.

The 2 processes talk over the binary’s stdin and stdout, one JSON object per line. The binary draws on /dev/tty, so stdout stays free for the protocol.

Ruby to Rust:

{"type":"say","text":"Done.","as":"markdown"}
{"type":"print","text":"partial text"}
{"type":"thinking","text":"Reading the file first."}
{"type":"doing","header":"+ read({\"path\":\"README.md\"})"}
{"type":"waiting"}
{"type":"ask","prompt":"> "}

Rust to Ruby, once per ask:

{"line":"fix the failing test"}
{"line":null}

null means the user pressed Ctrl+D, which ends the session. The binary also understands oops and display_file events, but the Ruby side does not send them. A line it cannot parse is reported on stderr and ignored.

Limitations #

• The log pane does not scroll. Rows are drawn from the top, so once the pane is full, new output lands below the visible area.
• Line editing is limited to typing and Backspace. There is no cursor movement, history, or tab completion.
• At a prompt, Ctrl+C types a c. Use Ctrl+D to quit.
• The as field is ignored, so errors look like any other text.
• Needs /dev/tty, so it will not run on Windows.
• ask behaves as it does in elelem; the full-screen UI is only used by chat.
• The repository has no specs yet.

Development #

git clone https://git.mokhan.ca/elelem/ratatui.git
cd ratatui
bin/setup
bundle exec rake compile
bin/run

Run bundle exec rake compile after changing anything in rust/. The development Gemfile includes elelem-builtins, elelem-llama, and elelem-ollama.