Jusi

Jusi is the Python backend for notebook-style execution used by the jusivim Vim/Neovim plugin.

It is responsible for:

• kernel lifecycle management
• notebook execution coordination
• per-cell client lifecycle
• plugin handler supervision
• protocol events and transport metadata for the editor side

Jusi is designed as part of a two-component system:

• jusivim editor plugin
• Jusi backend

The backend may run locally or remotely depending on the selected session target.

Entrypoints

Primary editor-facing entrypoint:

• backend root process: python -m jusi

Internal/support entrypoints used by the backend and jusivim:

• native terminal attach: python -m jusi client-process terminal-attach
• plugin runtime starter: python -m jusi plugin-runtime
• transcript runtime entrypoint: python -m jusi client-runtime

Normal usage is through jusivim, which starts and talks to the backend over the Jusi protocol.

Protocol Features

The backend protocol supports:

• session start and attach
• cell execution
• interrupt and input reply
• disconnect and reconnect
• client inspection and shutdown
• structured handler messaging for plugin follow-up and completion
• native terminal transport advertisement for interactive handlers

Session metadata may also include:

• plugin_specs: editor-facing presentation defaults keyed by magic name
• palette: editor-facing plugin creation metadata keyed by magic name

Cell metadata may include:

• presentation: authoritative post-handoff presentation metadata for an executed cell
• runtime_mode: backend-owned runtime mode such as transcript or handler

Documentation

• Protocol
• Session Lifecycle
• Plugin Contract
• Architecture
• Backend Map
• Contributing

Development Note

Jusi is authored and maintained by notawhaleble. OpenAI Codex assisted with parts of the implementation and release preparation.