1. it's not just about MCP, if you have 100s of skills, you are going to have the same context issues

2. it was delegation to a subagent to select the tools that should be made available, which sounded like it got the whole list and did "rag" on the fly like any model would

You're going to want to provide your agent with search, rag, subagent context gathering (and pruning/compation/mgmt) that can work across the internet, code bases, large tool/skill sets, past interaction history. All of this can be presented as a single or few tools to your main agent and is the more meta-pattern/trend emerging