I have used this device for years in skirmish games and am now trying to get it down in writing. It MAY be original but I suspect I read something similar in another long-since-forgotten set of rules. See what you think.
COOL:
Every miniature on the table, except spell markers, is rated for his, her, or its "cool," which represents ability to decide or react appropriately under stress. Anytime an attempt is made to perform some task while in "combat" or in the presence of an enemy, a roll is made against COOL. Rolling higher than the COOL rating results in "blowing your cool" and failure, which means the action cannot be taken until the following turn.
EXAMPLE: A musketeer is trying to reload while being charged by an enemy. Will he succeed in time to get the shot off, or will his nervousness make him fumble about and be caught half-loaded?
CHARACTERS, named individuals with independent decision-making, have COOL ratings from 1 to 5.
Un-named rank and file fighters, townspeople, members of a warband, etc. have COOL ratings of 0 to 4. They will perform better when commanded by a CHARACTER whose COOL they "borrow" and use.
EXAMPLE: A squad of raw militia, undrilled, have a COOL of 1, but the veteran sergeant commanding them has a COOL of 3. If the sergeant makes his COOL, his men will obey his order. If the sergeant "blows his COOL" then each of his men must use his own COOL, and will either freeze or panic unless he rolls a 1.
In general, COOL ratings are assigned before the game along these guidelines:
A COOL of 0 represents those whose default position is either to freeze in terror or indecision, or to "run around and scream and shout." Young children and some civilians, especially facing a situation completely outside their experiences, are examples.
A COOL of 1 would be most civilians including raw militia.
A COOL of 2 would be trained but inexperienced ("green") fighters, and civilians in leadership roles.
EXAMPLE: a school teacher might have a COOL of 2, while his students would have either 0 or 1.
A COOL of 3 represents veteran fighters.
A COOL of 4 represents elite veteran fighters. experienced and also confident in their own abilities.
For CHARACTERS, COOL ratings correspond to the above, but 1 point higher. For example, even a panic-prone fool of an officer still has a COOL of 1: he MIGHT make a good decision in spite of himself. A veteran elite officer has a COOL of 5, the maximum possible (and so can still "blow his cool" on a roil of 6.)
It is possible that the un-named troops might have a higher COOL than their officer. Elite veteran solders' COOL of 4 might exceed the COOL rating of 3 of their relatively inexperienced officer. But a successful roll against the officer's COOL of 3 is required if his men are to act TOGETHER. If the officer blows his COOL, his men each have 4 chances in 6 of acting correctly, but as individuals.
It is also a common situation that a lower-ranking CHARACTER has a better COOL (4) than his superior (3): a green lieutenant with a veteran sergeant. In such case test the sergeant's COOL first; if he makes it, he has succeeded in advising his officer (and the officer has listened!) and the men will respond as the sergeant-through-the -officer directs.
Players and the game master may choose how often to apply the COOL test. In general, when troops or civilians are doing tasks to which they are accustomed, and especially ones for which they are trained or have Standard Operating Procedures (SOPs), no test is needed. Other factors may include whether the enemy is out of sight, or out of range, or whether the troops feel safe, etc. Too many COOL tests slow play.
However, each player has the right to demand a COOL test by his opponent. This will be routine in close actions.
An example from a recent game:
A band of Comanches included several young bucks who had no firearms and desperately wanted one. They were on their first raid, with a COOL of 2. They responded as directed by the chief or other leaders, but the occasion arose that one of them killed his opponent and picked up his gun. He had now fulfilled an important individual victory condition, and the GM required a roll against his COOL of 2 for him to stay in the fight. He blew his COOL, and promptly rode home in triumph, waving his new rifle, and abandoning the fight.