The Planar Binding spell is not really clear about how exactly the opposed Charisma-check is performed. This is particularly interesting for the Blood Summoner archetype, but also for other callers.
How quick can you do it? You have to describe the task, but the rules say:
Quote:
Speak
In general, speaking is a free action that you can perform even when it isn't your turn. Speaking more than a few sentences is generally beyond the limit of a free action.
As soon as the creature is summoned can you immediately make a check to bind it and compel it to serve you?
Otherwise, what kind of action is it?
This is generally of great importance, as the Magic Circle doesn't protect you from ranged attacks of the called creature.
If you can immediately make a check is the trap even necessary?
The description seems to imply that you need the magic circle but is unclear if the dimensional anchor is obligatory for called outsiders that can change plains, or if it is only necessary to "keep it bound for as long as you dare".
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If the creature does not break free of the trap, you can keep it bound for as long as you dare. You can attempt to compel the creature to perform a service by describing the service and perhaps offering some sort of reward.
So, is the trap part of the magic of the binding, or is it only highly-advised?
Or are you supposed to wait until the trapped outsider has tried to escape in all possible ways, before you can try to compel it? This doesn't really make sense though, because then the outsider could just wait a few days without trying to escape.
And what if you want to call a creature, but not bind it (e.g. an allied outsider from a different plain, or a creature that you worship)? Can you in this case leave the trap away?
Another clarification is needed here:
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Once the requested service is completed, the creature need only to inform you to be instantly sent back whence it came. The creature might later seek revenge.
Does the creature have to do this? Can it not inform you and stay on the current plain indefinitely?
If not, can you make the report part of your service? I guess the service can be very complex if you take the time to describe it, but it does still have to be one task, right?
Also:
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Impossible demands or unreasonable commands are never agreed to.
What does unreasonable mean here? Such commands that are not logically consistent? Otherwise what marks an unreasonable command?