Haven't looked at rtk closely but from the description it sounds like it works at the CLI output level, trimming stdout before it reaches the model. Context-mode goes a bit further since it also indexes the full output into a searchable FTS5 database, so the model can query specific parts later instead of just losing them. It's less about trimming and more about replacing a raw dump with a summary plus on-demand retrieval.
Yeah I like this approach too. I made a tool similar to Beads and after learning about RTK I updated mine to produce less token hungry output. I'm still working on it.
