The Shepherd, which brings in the apps that wander in the background

How the Shepherd finds the apps busy in the background (battery and memory hogs, and apps that keep starting themselves), what starts with Windows and what each uses, and what it never lists.

Article: 3401
Applies to: Shepherd 0.2.20
Last reviewed: October 9, 2026
For: For everyone

Written for Shepherd 0.2.20. Shepherd is at 0.2.21 now (1 small release since: what changed).

What the Shepherd does#

The shepherd walked the hills for the sheep that had strayed, and brought them back to the fold. The Shepherd finds the apps that wander in the background, using your battery and memory while you aren't looking.

It never closes anything, or changes what starts with Windows, on its own. It does those only when you tick them.

It holds the Pinder's office on an everyday PC while Castellan's developer features are off. On a gamer's PC, the Constable holds it, and the Shepherd works behind it; with developer features on, the Pinder holds it.

The Shepherd comes with the Household license.

What it lists#

Every 10 minutes it takes a quick look, changing nothing, and lists:

Kind	What it means
On battery	An app with no window that used notable processor time while the PC ran on its battery. Listed first: it's the drain that matters most.
Background apps	An app with no window that, over 30 minutes, used more than 2% of a processor core, or held more than 500 MB of memory of its own.
Relaunchers	An app with no window that keeps starting again: closed and back within the hour, three times a day.
Memory kept for closed apps	A program that holds on to the memory of apps that have closed, out of sight of Task Manager. Over 200 closed apps, or 1 GB, and growing.
Starts with Windows	What starts with Windows for you, as Task Manager's Startup apps page has it, with how much each one used since.

An app is the program and every helper it started, together. An app with a window isn't a stray, however busy: it's in front of you, and you can close it.

What it never lists#

Windows' own programs and services.
Security software.
Drivers' helpers: sound, graphics, touchpad and the like.
Castellan and its agents.
Developer tools: editors, terminals and the like. Those are the Pinder's.
What you told it to leave be.

A line on each app#

The local AI says in one line what each listed app is, so you know what an unfamiliar file name belongs to: "Part of the printer software: checks for ink levels", say. It's labelled with where it was written, and unverified. The list never waits for it. Without the local AI, the list is the same. See Set up the local AI.

Its page#

The Shepherd's page is at http://shepherd.localhost:20707/, and Open on its card in Castellan goes there. It shows the last round and Run now, whether the PC is on battery, the strays, what starts with Windows, and a log of what you closed or turned off. See Close an app, or keep it from starting with Windows.

Its settings#

Setting	Default	What it does
Notable CPU above	2% of one core	What counts as busy.
A lot of memory above	500 MB	Of its own.
Left be	None	Apps never listed.
A round every (Advanced)	10 minutes	A round only looks.
Averaged over (Advanced)	30 minutes	How far back processor time is averaged, and memory must hold.
A relauncher at (Advanced)	3 times a day
Back within (Advanced)	60 minutes	Closed and back within this counts as a relaunch.
Notes per round (Advanced)	10	New AI notes a round.

What it can't do#

It needs 30 minutes before it lists anything for processor or memory, and a day's rounds on battery before a drain shows.
An app running as an administrator is listed by name only, and can't be closed from here: use Task Manager.
Store apps that start with Windows aren't read yet.
Memory is what an app holds for itself. Task Manager may show less.

Is this page right?

If something on it is wrong or out of date, tell us and we'll fix the page.

Still stuck? Write to support@castellan-software.com and mention article 3401. Every version of Shepherd, and what changed in it, is in its release notes.