The spec promised that the first live task would measure xrefs. It never did: the plan measures model space, paper space and block definitions. 1.6 does not read an xref's own entities on either engine; the host drawing is what gets read. The snapshot docstring and drawing_understand's docstring now say so, and nothing is claimed about the live engine that was never measured. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd