Guide to Prime Directive rules

Commander Doogal McToot’s guide to Prime Directive’s mechanics


Here is a quick FAQ for the main Prime Directive rules most commonly used. Subjects herein cover tricodes, Success Levels, tasks, modifiers, initiative, damage, dying, healing, defences, armour and how to shoot the bad guys.

I hope this helps.

What is a TRICODE and how do I use it?

A Tricode is a sequence of 3 numbers that represent the various success levels you can achieve at any given task, check or attack. Tricodes represent:

(1st number) MINIMAL success / (2nd number) MODERATE SUCCESS / (3rd number) COMPLETE success

Tricodes always have the lowest (minimal number first) and can look like this: 2/4/6, 4/7/10, or 3/6/9


What happens if I fail to meet minimal success on a check?

The highest number you rolled is compared to the minimal success number of the Tricode. If the number was HALF OR LESS of the requires minimum success level, the player has BOTCHED. If it is less than Minimal success but higher than a botch, the player has merely FAILED.

Please note: You cannot BOTCH any task whose minimal success level was 1 or 2.


How do I use a skill I have?

Using a skill you have to perform an action is called a SKILL TASK. This is analogous to a Proficiency or skill check in D&D.

To perform a skill Task, roll the number of D6 in your DICE score for the skill and compare your highest dice against that skill’s modified Tricode. That is your SUCCESS LEVEL.


How do I use a skill I don’t have?

You can attempt to use skills you don’t have. This is highly dangerous and is called an UNSUPPORTED SKILL CHECK. Your skill in this area is Zero so the amount of dice you roll is equal to half of the supporting characteristic (rounded down). In addition, the tricode for the task is DOUBLED (so a 2/4/6 becomes a 4/12/16).

Roll your number of D6 for the check and compare the highest number against the modified tricode. That is your SUCCESS LEVEL. Warning: look out for the BOTCH result – it’s highly likely with this kind of check.


How do I use my statistics to do a task?

Sometimes what you are doing doesn’t require a skill and your characteristics will be used. This is called a CHARACTERISTIC TASK and is similar to an ability score check in D&D.

To perform a Characteristic check, roll a number of D6 equal to your characteristic. Compare the highest result against the task’s tricode. That is your SUCCESS LEVEL.


What are the SUCCESS LEVELS?

BOTCH:- Catastrophic failure of the task. Horrible things are about to happen to you and the team! Think of this as the natural 1 in D&D.

FAILURE:- You’ve screwed up. You fail to meet any part of your desired outcome. This is usually embarrassing or time consuming but depending on the situation a fail can also be highly dangerous (E.G If you FAIL to dodge that incoming asteroid storm don’t think you get away simply embarrassed!)

MINIMAL:- You didn’t fully succeed but have made a small amount of progress on the task you were attempting. Typically, a minimal success represents around 11% of what you were trying to do.

MODERATE:- You didn’t fully succeed but have made a reasonable amount of progress on the task you were attempting. Typically, a moderate success represents around 33% of what you were trying to do.

COMPLETE:- You succeed in what you were trying to do.

Remember, ONLY YOUR HIGHEST DICE on any given check provides you the success level for any given task check (see below). Also, multiple successes from subsequent attempts can stack up, with 3 moderate successes needed for a Complete success or 3 minimal successes required for a moderate success.


What tricode do I need to roll for skill [insert skill name here]? 

All skills have different Tricodes to use. These are listed in the Prime Directive rulebook. I’ll get a full list published for the game.


What are tricode modifiers and how do they work?

Sometimes a task is made easier or more difficult. There are two types of modifier, FLAT and EXPANDED.

A FLAT modifier adjust all levels of the tricode BEFORE the check is made. Plus modifiers are bad, minus modifiers are good. A tricode of 2/4/6 with a flat +1 modifier becomes 3/5/7.

An EXPANDED modifier  applies a different change to each level of the tricode. It’s usually applied when a complete success is made significantly more difficult than a minimal success. These modifiers appear like tricodes, with the first number relating to minimal success numbers, the second to moderate and the third to complete success. Plus modifiers are bad, minus modifiers are good. A tricode of 2/4/6 with an expanded modifier of 1/2/3 becomes 3/6/9. A tricode of 2/4/6 with an expanded modifier of +0/0/+2 becomes 2/4/8.


How can I oppose a check made against me?

Sometimes you can resist a check made against you. This is used a lot when trying to escape from grapples, resist persuasion or reverse a hacking attempt in progress. This sort of check is called a RECIPROCAL RESPONSE TEST and is equivalent to an opposed check in D&D.

When both characters involved are using the same skill or characteristic for the check (tug of war, running, computer hacking, etc) the player with the highest check result for the task usually wins. For longer tasks your success level gives you points towards a total number required instead that will be tracked across subsequent attempts.

Opposition Success Level achieved

Success level change applied to opponent’s check


-3 levels for opponent


-2 levels for opponent


-1 level for opponent


No effect


+1 level for opponent

 When characters are using different skills to oppose one another (persuasion, psionic probing etc) a special tricode is used. It is 2/4/6 with a flat modifier equal to the number of dice the opposition rolled for their check.
If a success on this opposition check is achieved the SUCCESS LEVEL of your opponent is reduced according to this table:


How do I roll initiative?

To do an ACTION/INITIATIVE test, perform a SPEED characteristic check against a tricode of 4/6/8. Do two things with all the rolled dice:

  1. DETERMINE LEVEL OF ACTION (LoA) by comparing the highest dice to the tricode. This represents WHAT YOU CAN DO this turn.
  2. DETERMINE INITIATIVE LEVEL by adding up all the successes you have rolled. Minimims get you 1 point, Moderates will give you 2 points, completes give you 3 points. This tells you WHEN YOU WILL GET TO ACT in the turn (this is the same as normal D&D initiative. Higher numbers act fastest)

How many actions to I get in a turn?

Your LEVEL OF ACTION from the initiative roll determines what you can do in a turn. Compare your level of action result to the table below to find out how many actions and moves you get:

Action/Initiative success level rolled

Level of Action granted

What actions do you get

Modifiers to any defensive actions




  • Perform 2 simple actions (“do this then do that”)
  • Perform a simple action AND move up to your MOVEMENT rate
  • Move twice you MOVEMENT rate





  • Perform a simple action AND move ½ your MOVEMENT rate
  • Move up to your MOVEMENT rate

+1 flat modifier



Perform a simple action and move up to 1 meter

+2 flat modifier



No actions or moves. No modifier to next A/I test if initiative is zero.

+4 flat modifier



No actions or moves. +2 modifier to next A/I test.

No defences allowed


What happens if I score no points on my initiative check?

You go last and you suffer a +2 penalty to your next ACTION/INITIATIVE test.


Can I hold/delay my actions?

You can hold your actions until later in the initiative order if you want but if you do not act in a turn you lose your actions and moves entirely. No waiting for next turn to react to an opponent move/action/attack!


How does a combat turn work?

Combat is broken into 4 phases: TIME, POSITION, ATTACK and DEFEND.

In the TIME portion, players and opponents get their initiative scores sorted

In the POSITION portion, Players and the GM outline the relative positions of combatants and scenery

In the ATTACK portion you use your actions to attack!

In the DEFEND portion you use your skills to try and dodge, resist, oppose etc. and apply damage dealt.

While the game defines these as distinct phases, you’ll find that as this is an experienced group of roleplayers these phases will essentially interact a lot and may not appear so formal as presented in the rules.


How much time is in a combat turn?

A turn is 4 SECONDS LONG. Time in Prime Directive is counted in TICs and TOCs (Time In Combat and Time OUT of Combat). A single simple action grants 1 tic to perform. Skills and tasks often have a TIC cost – this is essentially how many actions in a combat round (or subsequent combat rounds) have to be expended to perform it.

Mostly actions are 0, 1 or 2 TICs. Zero TIC cost actions are like FREE actions in D&D – these are tasks so simple that they can be performed during other tasks (pushing buttons, dropping items, shouting warnings etc). Common 1TIC actions include aiming, firing weapons opening doors and so on.

Characters cannot do infinite 0TIC actions just because they are 0TICs to perform. Any given 0TIC action can be performed ONCE during a turn so no pushing 1000 buttons on a console in 4 seconds just because pushing a button is 0 TICs!


What are defensive actions and how do I use them?

After you’ve been attacked you can attempt to reduce or negate damage by way of defensive actions if you rolled a high enough LEVEL OF ACTION as part of the ACTION/INITIATIVE test (see above). There are three defensive options: DODGE, PARRY AND BLOCK.

  • DODGE is used against incoming fire. To dodge a shot from an opponent: Perform a SPEED characteristic task against the tricode of 4/6/8 modified for LEVEL of ACTION and successive defensive checks.
  • PARRY is used against melee attackers when you have a melee weapon in hand. To parry an incoming blow: Perform a MELEE SKILL task against the tricode of 4/6/8 modified for LEVEL of ACTION and successive defensive checks.




All damage negated


-4 to damage taken


-2 to damage taken


Take full damage


+2 extra damage taken

  •  BLOCK is used in hand-to-hand martial arts. To block a fist, foot or tentacle (hey, it happens!): Perform a MARTIAL ARTS task against the tricode of 4/6/8 modified for LEVEL of ACTION and successive defensive checks.


As usual, compare your highest die to the tricode to get your success level. Compare the success level, in the table on the right:


Ordinarily your character gets ONE defensive action a turn, modified for the LEVEL OF ACTION you have. To use multiple blocks, parrys and dodges a character must spend a simple action on being defensive during his action. This allows him/her as many defensive actions as he/she wants during a turn. Defensive actions get HARDER the more of them you perform in one turn! Apply an extra +1 flat mod to the defense action tricode for every additional defence you perform.

HINT: You can reset the modifier by using your second action on defensive manoeuvres at any point during the sequence of attacks. Just in case you have a complex LoA and are being mobbed by high-initiative dudes J


Does Armour stop attacks or reduce damage?

Armour doesn’t make you harder to hit, it stops damage AFTER the effects of defensive actions have been taken.

Armours have three damage reduction ratings, similar to tricodes, and typically look like this: 3-3-5 or this 2-0-1. These three numbers represent how much damage armour absorbs from three different types of attack:

ENERGY ARMOUR is the 1st number. This negates a number of damage points taken from lasers, beams, and similar weapons and effects.

KINETIC ARMOUR is the 2nd number. This negates a number of damage points taken from impact attacks such as clubs, disruptors and rams.

EDGE ARMOUR is the 3rd number. This negates a number of damage points taken from blades and other cutting or slashing attacks.

If, after you defend an attack, you are taking 4 damage, apply the relevant number from your armour to reduce the damage you take. Armour is passive protection and usually only needs to be worn to take effect although partial armours and personal shielding may have weak spots with lower damage reduction or require active use.


Enough jibber-jabber about rules. How do I shoot the bad guys?!

Fair enough. To attack you use the appropriate weapon skill or characteristic test against a combat tricode of 4/6/8. As usual, use the highest D6 you roiled to determine the SUCCESS LEVEL. Each type of attack has it’s own set of modifiers which need to be applied to this tricode (for range, stun damage, injuries, movement etc.) The tables look scary but are reasonably intuitive once you are used to them.

Compare your SUCCESS LEVEL for the attack to the damage numbers for the weapon and setting you used. The damage numbers are usually presented like a tricode. Apply the right number according to the success level achieved.


Do Phasers and such run out of batteries?

Yes. Amount of power/ammo in each weapon is listed in the weapon descriptions. Some fire modes use more power (the higher the lethality, the more power is typically consumed). If you’re out of power or ammo, you can’t shoot until you reload or recharge. Bring some Star Trek Duracell to extended fights. J


So, if bad guys shoot back, how do I know when I’m dead/knocked out?

You have two damage tracks, STUN and LETHAL. As damage is applied to you from weapons, mishaps, indigenous life forms, radiation, etc. it will come off one of these tracks. Stunning weapons, bruising damage and similar types of damage come off stun. Stabbing, shooting and anything that will break bones/cause blood to be lost will come off lethal. Damage can overflow from stun to lethal if you take too much damage.

If you have no more stun left, you’re knocked out. If you have no more lethal, you are dying and need immediate medical attention from a trained surgeon. If you take over twice your lethal damage capacity (or don’t get surgery in time) you are DEAD – get rolling up a new character!


 If I’m dying, how long does a medic have to do surgery on me?

Once all his/her lethal damage capacity is gone a character dies in a number of minutes equal to their total damage capacity MINUS the total amount of lethal damage taken.  For instance, a character with a lethal capacity of 6 dies in 4 minutes when they’ve taken 10 damage. Get your medic to beam you back to sick bay, pronto, if you are down!


How do I heal?

Characters can recover stun or lethal damage in the following ways:



FIRST AID from another character

Every 5 minutes a stunned character can attempt to shake off their stun. This is very rarely done in combat as each round is only 4 seconds long. To perform stun recovery a character rolls a number of D6 equal to his stun capacity divided by 2 (rounded down) against the tricodes below:



1 or more boxes of stun filled in


Half or more boxes of stun filled in


All boxes filled in (unconscious)


Another character with First Aid/Medicine and a med kit helps recovery

-4 flat modifier to the above

1 hour has passed

No tricode – heal 1 point of stun automatically


Once you have a SUCCESS LEVEL for the stun recovery check, apply the following effects to your stun damage:




Remove all stun damage


Remove half stun damage (rounded down)


Remove 1 box of stun damage


No effect. Try again in 5 minutes


No effect. Try again in 10 minutes and apply +1 flat mod to check.


To recover lethal damage, a character can make a healing check once every day starting 24 hours after the last box of lethal damage was applied. To perform a healing check a character: Rolls a number of D6 equal to his maximum lethal damage capacity divided by 2 (rounded down) and compares the highest die to the following tricodes:



1 or more boxes of lethal filled in


Half or more boxes of lethal filled in


All boxes filled in (death’s door – needs SURGERY to survive)



Once you have a SUCCESS LEVEL for the healing check, apply the following effects to your lethal damage:




Heal one lethal box and test again immediately. Cannot Fail or botch this bonus test.


Heal one lethal box


No effect. Try again in 24 hours


No effect. Try again in 48 hours


Apply 1 extra box of lethal damage. Next healing check gets a +2 flat modifier to the tricode.


NOTE: There is a TON of modifiers for the healing check (facilities, environment, whether first aid was applied on scene or not etc) but for space these won’t be included here.

Hang on, there’s a lot of times I seem to need to roll higher than 6 on a D6. What gives??

Calm down. You CAN roll higher than 6 on a D6. When you roll a 6 in Prime Directive it is treated as a 5 PLUS the result of the next roll. You can keep rolling as long as you keep rolling 6’s.

For example, a roll of a 6, a 6 and a 4 is scored as: 5 + reroll 5 + reroll 4 = 14

For another example, a roll of 10 can be achieved by rolling a 6 then rolling a 5 (or 5 + reroll 5)



Guide to Prime Directive rules

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