1. Tends to use embeddings with a similarity search. Sometimes called "retrieval". This is faster but similarity search doesn't alway work quite as well as you might want it to.

2. Instead lets the agent decide what to bring into context by using tools on the codebase. Since the tools used are fast enough, this gives you effectively "verified answers" so long as the agent didn't screw up its inputs to the tool (which will happen, most likely).