Same agent, but the caller also hands over a Sources object.

Actions in the order they ran:
  com.ankurm.agents.embabel.ResearchAgent.summarise
  com.ankurm.agents.embabel.ResearchAgent.writeBrief

Prompts the LLM received:
  Summarise these notes in one sentence: A note we already had.
  Write a two-line brief titled 'virtual threads' from: Virtual threads make blocking cheap.