Sentry puts the ship to sleep. It wakes up when a foreign ship enters its sensor range.

Guard puts the ship to sleep. It stays there until you wake it. If someone attacks, it (naturally) defends itself.

Sentry is semi-useful. Guard less so. Have used guard to "park" ships so that I'm not bugged every turn to move them. This has the danger that you forget they exist...

My ideal implementation for "sentry" and "guard" would have been:

Sentry: Sleep until enemy ship comes into sensor range. Activated sentry ships are the first to move.

Guard: If a foreign ship enters the movement range of a guarding ship, it must attack it. With the implication that if the foreign ship's faction does not want to go to war with the guarding ship's faction, it can't enter the guard's movement range. (Obviously the AI must also be made to use the guard feature against you...)

Guard is great but kinda weird... arguably its just "stay"  and don't bother me... which should just be default behavior with a options check box for "alert me to idle ships"

guard will ignore everything. Always. It just stays put. Sentry will "wake up" if a ship gets close.... or rather within sensor range, which can be quite big, and can make it less useful.

Because if it wouldn't you could lure that ship away. Let's say you want a ship to guard a specific spot, if that ship would fly off to attack a close enemy it would run into the risk of not getting back in one turn, leaving the spot exposed to be attacked or taken by others.

Nevertheless, both options are sub-optimal at best.

What we need is a patrol option, and a auto-attack/retreat option that can be specified via a few logical commands

(like;

- engage/retreat only if stronger/weaker

- engage/retreat always

- attack only <specified vessels>

etc

Well, presumably a friend wouldn't then move into range in the first place, and if the enemy was too strong then clearly your guard detail was too small...

What I was actually after was that your planetary defense fleet would automatically block foreign ships from moving into a striking distance of your planet unless the enemy ships actually did choose to attack and DOW you. The real world analogy would be the situation where a foreign unauthorized plane is flying towards your national airspace and you scramble your jets to intercept it and to escort it out.

Doesn't sentry wake up upon any foreign ship, not just an enemy ship? I remember being annoyed by that as I constantly had to re-sentry ships because of "false alarms".

Of course, some civilizations use the same word for "enemy" and "foreigner" so maybe it's not that odd...