[jdh]

To add a bit more to the above, I think the discussion up until this point has been to support the assignment of a task to multiple contexts in an OR fashion, rather than the AND fashion that's being suggested above.

In other words, I can certainly see the point of having a task assigned to two or more individual contexts in which I may be able to perform that task. IMHO, this is most relevant due to the availability of location-based searches for places -- for example I may have a task to "Buy Milk" which can be done at the Grocery store, the Pharmacy, or the corner store. In any other system I'd tag this as "Errands" and be done with it, but since OF on the iPhone allows me to setup locations for each context, it makes some sense to create contexts for my Grocery Store, my Pharmacy and my Convenience store so that I can have the task show up when I'm near any of those locations.

However, using contexts as an AND style intersection sounds like it would get frighteningly complex in most cases. I'd agree with the posters above that you either need to subdivide the task into a project or sub-task with additional context-specific layers, or you need to simply identify the most important context that is relevant.

In the above example, using @Garage makes sense as that's where you want to think about the installation of the safe. Having it completely cut off unless Fred is present or unless the required hardware is present is irrelevant. If you're standing in the Garage looking for something to do, the presence of that task is going to tickle you to follow-up on the other things you need to accomplish that task. Otherwise, you may never see the task because the requisite conditions will rarely be met.