Can an Eidolon apply a reach evolution to a weapon attack?

Question

Can an Eidolon apply a reach evolution to a weapon attack (such as a polearm)? The wording of the reach evolution does not seem to refer to natural attacks as most other Eidolon attack abilities do.

Reach (Ex)

One of an eidolon’s attacks is capable of striking at foes at a distance. Pick one attack. The eidolon’s reach with that attack increases by 5 feet.

When combined with a reach weapon, it seems this could easily grant a 15 foot reach. This seems to be very powerful at low level and I have concerns if this was intended.

Answer 1

As written, yes, you can combine that with a reach weapon.

3.X and PF rules are descriptive; that is, they generally tend to tell you what you can do. The RAW on the statement indicates that you can pick one attack - in the scenario you described, that'd be either 'manufactured weapons' or a specific weapon depending on the DM's interpretation of "one" - and the Eidolon gains another five feet of reach with it. Gaining reach in this fashion is fairly standardized, though this particular ability is not, and the flavor is admittedly a little odd.