I tried using Claude Web to help me understand a textbook recently.

The book was really big and it got stuck in "indexing". (Possibly broke the indexer?) But thanks to the CLI integration, it was able to just iteratively grep all the info it needed out of it. I found this very amusing.

Anthropic's article on retrieval emphasizes the importance of keyword search, since they often outperform embeddings depending on the query. Their own approach is a hybrid:

https://www.anthropic.com/engineering/contextual-retrieval