The main role of User Assistant Agent (UAA) is to assist user with relevant knowledge/suggestions, which are applicable on current user situation. In UAA, we understand experience though notes entered by user. Such notes are displayed to the users in same or similar context. Thus UAA helps users in collaboration and knowledge sharing. Notes can be generated also automatically (e.g. past workflow and result notes generated by KAA-WXA). Notes can also contain reference to other resources such as workflows, results or images. The other UAA role is problem definition where user can describe his/her problem typing free text and relevant semantic description of problem is detected and processed by other K-Wf Grid components to build and execute workflows for given user problem. UAA is built on EMBET architecture developed in Institute of Informatics, SAS. This architecture is being extended during K-Wf Grid project and sometimes when we refer to EMBET or UAA this can be identical.