Receptivity is one of the key things that we look for when deciding who our summer teams work with. A host or partner that is receptive is one that is available, has capacity and is interested in both our teams having a great experience as well as furthering on their project. Good hosts are also receptive to their community - they usually have a deep understanding for what is going on in their context and are well connected and well respected. They see and imagine with a catalysts perspective. They don't subscribe to the faulty theology of 'these teams are bringing God here.'
Ask yourself: Am I getting timely responses to my questions? Do they seem to have the capacity and availability for us or are they too busy? Can they imagine how this will be good for their momentum as well as our team? Do they have a solid strategy for follow on relationships after my team leaves? Are they well connected? What is their reputation like?
Trust me and do yourself a favor - only send teams to work with hosts that are receptive. If they don't have time or availability for you now, they also won't after you get there. You are hoping that it will be better but it won't.