pi-theme-switcher

Pi extension that automatically switches the terminal theme between dark and light based on environment variables, THEME_MODE, or time of day. Each mode can use a custom theme instead of the built-in dark/light themes.

Installation

pi install npm:pi-theme-switcher

How it works

On TUI session start, the extension evaluates the theme in this order:

1. PI_AGENT_THEME — set to "dark" or "light" to force a theme
2. THEME_MODE — set to "night" (dark) or "day" (light)
3. Time of day — fallback to dark/light based on system clock (configurable window)

The extension polls every 60 seconds to handle time-based transitions during long TUI sessions. It does not run in RPC, print, or JSON sessions where no terminal TUI theme can be changed.

Configuration

Create a config file at ~/.pi/agent/theme-switcher.json (global) or .pi/agent/theme-switcher.json (project-local):

{
  "nightStart": 22,
  "nightEnd": 6,
  "darkTheme": "rosepine",
  "lightTheme": "rosepine_dawn"
}

• nightStart (default: 23, 11 PM) — hour to switch to dark mode
• nightEnd (default: 7, 7 AM) — hour to switch to light mode
• darkTheme (optional) — theme to use in dark mode instead of the built-in dark theme
• lightTheme (optional) — theme to use in light mode instead of the built-in light theme

Configure both nightStart and nightEnd together, or omit both to use defaults. A config with only one of these fields is ignored. When nightStart > nightEnd (e.g., 22–6) the night range wraps around midnight. When nightStart <= nightEnd (e.g., 0–5), it does not.

The darkTheme and lightTheme fields are independent and optional. Each falls back to the built-in dark or light theme when omitted. The environment variables still select the dark/light mode; the mode is then mapped through this config. For example, with the config above, PI_AGENT_THEME=light applies rosepine_dawn rather than light.

Theme names refer to any theme available in Pi, including custom themes from ~/.pi/agent/themes/, project .pi/themes/, or packages. See Customize Pi with themes.

If a custom theme cannot be loaded, the extension applies the built-in theme for the selected mode (dark or light). It retries the custom theme on later polling ticks.

A config may contain only theme fields; the default night range then applies.

Project config overrides global config when the config file is valid.

License

MIT