Definition
Plain language
A case-board of research ideas where each card holds evidence, an interpretation, and a pointer to the code that tested it.
As stated in the literature
Arbor's central data structure: a hierarchy of hypotheses with attached experimental results and rewritten summaries propagated up to ancestor nodes, serving simultaneously as search frontier, long-term memory, and audit trail.
Why it matters: It gives a research agent one structure that doubles as its to-do list, its memory, and a record auditors can trace back through.
For example, each idea card holds the experiment that tested it, what the result means, and a link to the exact code that produced it, with lessons bubbling up to the parent cards.
Heard on the show
“The heart of it is a data structure they call a hypothesis tree, and the best way to picture it is a detective's case board.”Episode 131 — Why Autonomous Research Agents Forget Their Own Lessons, and Arbor's Fix