The introduction to Compendium of Spells in Other kinds of spells says
Compendium of Spells deals exclusively with the spells used by the classes and prestige classes introduced in the Player's manual Y Dungeon Master Guide, but even if you're playing a different spell class, you can use this book. The following advice should help you decide how to adopt spells for your character.
If the spell class or prestige class you are playing is not mentioned here, find a similar class and follow their advice. In addition, many new classes and prestige classes refer to the spell lists of existing classes. If your spellcaster uses the spell list of a character class mentioned in Chapter 2, your character gains access to all the spells presented for that class.
When deciding if other classes should have spells added to their spell lists, consider the tips below. (3)
So he Compendium of Spells offers some tips for different classes, including, for example, the shugenja ("Add spells with strong elemental or climate themes[; t]The spell list of the druid is a good place to look "(4)) and the shaman:
Shamans have a spell list that is a mix of druid and cleric, but they should not make all spells and clerics do. Examine the spell lists of both classes for good choices. Also, consider using the clerical domains presented in this book as shaman domains. (ibid.)
In other words, the DM is assumed, as is typical of D & D 3.5-Use the advertisements provided in the Compendium of Spells to report their own decisions on how to expand the spell list of a particular class.