What is an "effect" for the Chronomancer Rewind ability?

[Ifusaso]

The Chronomancer archetype for Wizards uses the vague term "effect" in their Rewind feature. I'm wondering what counts as an effect.

Rewind wrote:

As an immediate action after losing a spell due to a failed concentration check or after casting a spell that had no effect (such as due to successful saving throws, a failed caster level check to overcome spell resistance, or other immunities), the chronomancer can expend a number of points from his temporal pool equal to half the spell’s level (minimum 1) to immediately prepare the spell again, as if it had not been cast. Any material components expended in the original casting remain expended, as are actions used to cast the original spell.

Specifically, I'm looking at how the ability interacts with counterspells. Would a different creature expending an action and spell be considered an effect? Or do only the spells written effects count for this purpose?

[CBDunkerson]

effect: (noun) a change which is a result or consequence of an action or other cause

[emeramber]

"both spells automatically negate each other with no other results."

In my games, the chronomancer could regain it, but I could see a GM declare that it technically negated a spell, and thus couldn't. Of course, if you cast a scorching ray on an unaware red dragon, you just made it aware of your presence, which a GM could declare as an effect if they wanted. Or even "oh, that adventurer can cast that spell" increased their understanding/knowledge, so no rewind. I'd suggest reading it as if the spell had any of its text based effects. ot may cause corner case oddities, but is the simplest to adjudicate.

[CBDunkerson]

Casting a spell removes it from your list of prepared spells (for prepared casters) or reduces your available spellcasting slots (for spontaneous casters)... which is an effect. Ergo, Rewind ONLY works after a failed concentration check.

OR we could go with basic reading comprehension and logic to deduce that they are talking about whether the spell had any part of its intended effect on the target(s). If a fireball did one point of damage to one of twenty targets in its area then it had an effect. If a fireball did no damage to any of the targets in its area then it had no effect... even if it incinerated half a dozen chairs that also happened to be in the area.

[blahpers]

I wouldn't expect this particular ability to have to take the caster's intentions and state of mind into account to determine whether it can be used. Then again, it wouldn't be the first time a rule did something like this.

This ability is a hot mess.

[Cevah]

I note that the listed examples are all passive ways of failing to land a spell. Counterspell is an active force against the spell.

As a GM, I would not allow a rewind of a countered spell.

/cevah