D122 - Knowledge is a file the loop writes

Status: decided Date: 2026-08-20

What is known about a guest function - arity, argument meanings, return kind, edge cases - lives in the knowledge TOML under orbistoun-hle, written by orbistoun-cli learn and merged rather than replaced. It is never stored in the generated symbol database, which a search overwrites. An unknown arity is absent, not zero, and a test holds that guest_module! declarations never contradict it.

Why: a name can be regenerated; a measured fact costs an experiment and cannot. Two stores with different lifetimes share a key without duplicating content. Zero is a real arity a trace renders differently from "unknown".

Rejected:

• Facts in the generated database: destroyed on the next search.
• Facts in decision prose: recoverable only by grepping.
• Arity compiled into declarations alone: answering it needs a rebuild.