model_harness
AI Agent Model-family-aware agent harness. Selects, by model id/family, a base/harness system-prompt fragment and a preferred file-edit format (string-replaceedit_file vs apply_patch).
The default profile reproduces the current generic behaviour exactly, so
behaviour is unchanged when no family match applies. The registry is
data-driven and overridable; resolution is lazy with zero import-time cost.
Usage::

