How do companion perks work?

ESOUser0x00

Will they only be active once I max out their rapport or will it always be available regardless of rapport?
Also, Bastian should drop XP potions

RagnarSw

They will work if summoned or always available if you maxed their rapport and unlocked their keepsake.

Monte_Cristo

Active when you have that companion out on that toon. Once you've unlocked the keepsake, by reaching max level and rapport with them, plus doing some other tasks with them, the perks will always be active, on toons that haven't met any companions.

barney2525

To activate companion perks:

Step one - send all players 1 million gold ...