Overview: sessions, windows and panes for every host with the monitor enabled, refreshed on a poll, with per-pane CPU/memory/GPU metrics and a search across pane scrollback.
Control: create, rename and kill sessions and windows, split and kill panes, and attach a real terminal to a pane in place.
Tags: per-user labels on a session, saved per host so everyone who monitors it can tag it differently.
tmux.sessions: a service the ssh-terminal plugin consumes, optionally, to detect tmux on connect, attach or create a session, and wait for a new one to appear. The terminal keeps working without this plugin; it just skips tmux attach.

Every command runs over a pooled connection through ctx.ssh.withConnection, so it gets host key checks, auth providers, proxies and jump hosts like every other transport.

Layout

manifest.json         id, capabilities and what this plugin contributes
src/backend/           activate(ctx), routes, the tmux exec helpers, the service
migrations/            one .sql per dialect, generated from src/backend/tables.ts
src/frontend/          the tab, host action, session tree and pane preview
locales/en.json        its strings (English only; the rest are translated)
tests/backend/         vitest, node
tests/frontend/        vitest, jsdom

Data

p_tmux_monitor_session_tags, adopted from core's tmux_session_tags.
Host setting enableTmuxMonitor, copied from the ssh_data column of the same name by core's tmux-monitor-settings-migration.ts.

See packages/plugin-sdk/ARCHITECTURE.md for the contract this follows.