1. Introduction  
2. Modelling AGN-contaminated clusters using simulations  
2.1. Injections into simulated XMM observations  
2.2. XMM pipeline processing  
2.3. The extended and central point (epn) model  
3. Defining the AC parameter space  
4. The AC selection function  
5. The catalogue  
6. X-ray properties of the AC sample  
6.1. Count rate measurements  
7. Assessment of AGN contamination in the XXL survey  
8. Summary and conclusions