Architecture

Three design decisions explain most of bohay’s behavior.

A headless server, a thin client

The server owns everything: panes (real PTYs), the layout, agent detection, the session snapshot. It renders the whole UI into an off-screen buffer. The client is nearly stateless — it forwards your input and paints frames. That split is why sessions survive: the thing you close (the client) was never the thing that mattered.

One event loop, pure state

All state mutation happens on a single thread, driven by one event loop; slow work (git fetches, session-store scans, quality gates) runs on worker threads and posts results back as events. Single-writer state is why orchestration’s task claims and path leases are race-free by construction — no locks to get wrong.

Frames as diffs

The server doesn’t resend the screen; it sends only the cells that changed, coalesced into same-style runs. A keystroke costs ~22 bytes on the wire, a full 40-character line ~100 bytes. This is what makes remote attach over plain SSH feel local, and keeps the local render path around a millisecond per frame.

And the numbers

Pure Rust, a single ~3 MB binary, single-digit-MB resident memory even with panes full of scrollback, zero idle redraws (an idle session draws nothing). Performance is treated as a feature with a budget — changes that would make the hot path slower don’t ship.