Do thoughts create karma?
There is karma that is intention (an omnipresent mental factor) and karma that is intended actions.

Intended actions are defined by Je Tsongkhapa as:


  The actions of body and speech that are motivated by that intention.



Afflictions such as anger, jealousy, covetousness, and so forth are not the intention mental factor - but have their own entity as mental factors - therefore they are not karma. Anger manifests from a seed of anger and that seed is not a karmic seed, because it was "deposited" by a previous instance of anger (not by a previous karma - that is intention or intended action).

However, some qualify the afflictions as 'karmic path' or 'paths of actions' because they are likely to lead one to engage in negative actions (karma).