SubMiner/docs-site/plugins.md

Plugins

Plugins are JavaScript files that SubMiner loads at startup. A plugin can react to playback, run code on a timer, add actions you bind to keys, run programs, and show results in an overlay panel, all without rebuilding SubMiner.

::: warning Only run plugins you trust Plugins run inside SubMiner with the same access to your files and system as SubMiner itself. There is no sandbox. :::

These are SubMiner app plugins. The Lua script that runs inside mpv is the separate mpv plugin.

Install a plugin

1. Put the plugin in its own folder in plugins/ next to your config file, for example ~/.config/SubMiner/plugins/ai-explain/. The folder name is the plugin id.

2. Enable it in config.jsonc. settings is passed to the plugin as-is:

   {
     "plugins": {
       "ai-explain": { "enabled": true, "settings": { "reasoningEffort": "medium" } },
     },
   }
   

3. Bind its actions to keys with the __plugin-action:<plugin id>/<action> command:

   {
     "keybindings": [
       { "key": "Ctrl+KeyE", "command": ["__plugin-action:ai-explain/explain"] },
       { "key": "Ctrl+KeyT", "command": ["__plugin-action:ai-explain/translate"] },
     ],
   }
   

   To run an action from a script or a window-manager shortcut, use subminer app --plugin-action ai-explain/explain. It goes to the running SubMiner, or starts one if none is running.

4. Restart SubMiner. Plugin changes apply on the next start; keybinding changes apply immediately.

Load errors and plugin log output go to the app log with a plugin:<id> scope.

Example: explain the current line with Codex

The repository ships assets/plugins/ai-explain. It sends the current line, plus the lines around it, to codex exec and shows the answer in a panel. It needs a logged-in Codex CLI.

Action	What it does
explain	Translation plus a breakdown of the grammar and vocabulary
translate	Natural English translation, with a note only when it's unclear

Setting	Default	What it does
codexPath	"codex"	Codex binary. Use a full path if SubMiner can't find it on PATH
model	""	Model passed to codex exec -m; empty uses your Codex config
reasoningEffort	"low"	Codex reasoning effort; empty uses your Codex config
before, after	2, 1	Lines of context sent before and after the current line
pause	true	Pause playback when the panel opens
timeoutMs	120000	Give up after this long
prompts	{}	Replace an action's instructions, e.g. { "translate": "..." }

Press Esc to close the panel. Closing it, or starting another request, stops the running Codex process.

Write a plugin

A plugin folder needs a plugin.json:

{ "name": "My Plugin", "version": "1.0.0", "main": "main.js" }

main points to a CommonJS module (.js) or an ES module (.mjs) that exports activate(ctx). It may return a cleanup function, or the module can export deactivate(). On quit, SubMiner waits up to 2 seconds for it, including any promise it returns. Everything a plugin registers through ctx (listeners, timers, actions, panels, running programs) is cleaned up automatically when SubMiner quits.

function activate(ctx) {
  ctx.mpv.on('media-path-change', ({ path }) => ctx.log.info(`Now playing ${path}`));
  ctx.every(60_000, () => ctx.log.info('Still watching'));
  ctx.actions.register('hello', () => {
    const line = ctx.subtitles.current();
    ctx.ui.panel({ title: 'Hello', markdown: line ? `> ${line.text}` : '_No subtitle_' });
  });
}

module.exports = { activate };

An error thrown by a plugin is logged and does not crash SubMiner. A plugin that blocks with a long synchronous loop still freezes the app, so keep slow work asynchronous.

ctx reference

Member	What it does
id, dir, settings	Plugin id, plugin folder path, and plugins.<id>.settings
dataDir	plugin-data/<id>/ next to your config file, for caches and state. Exists before activate runs
log.debug/info/warn/error(message)	Write to the app log
every(ms, fn), after(ms, fn)	Repeating and one-shot timers. Return a function that cancels them
mpv.on(event, fn)	Listen to mpv events (below). Returns an unsubscribe function
mpv.command(args)	Send an mpv command, e.g. ['set', 'pause', 'yes']
mpv.getProperty(name)	Read an mpv property (Promise)
mpv.connected	Whether mpv is connected
mpv.ensureRunning()	Connect to mpv, starting an idle mpv if none is running. Resolves false if that fails
subtitles.current()	The displayed line as { text, startTime, endTime }, or null
subtitles.context({ before, after })	{ current, before, after }. Neighbors come from the loaded subtitle file, or recent lines for streams
actions.register(name, fn)	Add an action, bindable as __plugin-action:<id>/<name>
actions.run(actionId, payload)	Run a built-in action, the same ids keybindings use, e.g. openJimaku or mineSentence
notify(message, { variant })	Overlay notification. variant is info, warning, or error
ui.panel({ title, markdown })	Open the plugin panel. Returns { update(content), close(), closed, signal }
ui.openWindow({ html, preload })	Open a window from the plugin folder (below). Returns the Electron BrowserWindow
exec(command, args, options)	Run a program without a shell (Windows .cmd/.bat shims go through cmd.exe). Resolves { exitCode, stdout, stderr }
unstable	SubMiner internals. These change between releases without notice

A panel's signal aborts when the user closes it or another panel replaces it. Pass it to exec to stop work nobody will see. Only one panel is open at a time. Panel markdown supports headings, lists, quotes, code, bold, and italics; HTML is shown as plain text.

exec options are stdin, cwd, env, timeoutMs, and signal. It resolves for any exit code and rejects when the program can't start, times out, or is aborted.

ui.openWindow takes html and an optional preload, both relative to the plugin folder, plus title, width, and height. Opening the same html again focuses the open window. The page runs with context isolation and no Node access. The preload is sandboxed too: it can require('electron') but nothing else, so bundle anything more into it. Expose what the page needs from the preload with contextBridge, and handle its messages with ipcMain from require('electron') in the plugin. Prefix channel names with the plugin id. Plugin windows close when SubMiner quits.

mpv events: connection-change, subtitle-change, subtitle-timing, time-pos-change, duration-change, pause-change, fullscreen-change, media-path-change, media-title-change, subtitle-track-change, subtitle-track-list-change, secondary-subtitle-change, secondary-subtitle-track-change, secondary-subtitle-delay-change, secondary-subtitle-visibility, client-message, and end-file. end-file gives { reason, playlistEntryId, error }, where reason is eof, stop, quit, error, redirect, or unknown.