Lens: determinism

Lane: the boundary between script and prose. The bar: a script does work with one right answer per input; prose does work that turns on meaning. A line crossing either way is a defect.

• Prose doing work a unit test could check: parsing, counting, path resolution, rendering a template, validating structure, diffing. The signal verbs: validate, count, extract, convert, compare, scan for, check structure, list all, diff. High when paid on every invocation, medium when occasional and cheap. Name the script and its interface.
• Prose reading raw files to pull out a few facts (frontmatter values, token counts, inventories) where a pre-pass script could hand the model compact JSON: medium, high for large files.
• Scripts in scripts[] with has_pep723 or has_test false, or without --help: medium each. script_findings carries the detail; cite it, do not re-derive it.
• A script that defers errors to the model: swallows an exception, warns and exits 0, or returns partial output with no reason. High; the model will treat it as success.
• A script deciding meaning: a regex or string match classifying intent, tone or quality rather than locating a delimiter. Critical when it gates later behavior, high otherwise; it breaks when the phrasing shifts.
• Memory agent (shape_hint is memory-agent): prose maintaining an index of memory files, counting or sorting entries, or checking the sanctum's structure, when wake.py generates the map: medium. The model's tokens go to what to remember, not bookkeeping.
• A transcript or session log in hand: the same helper re-derived turn after turn is the strongest script signal. High; name the script that does it once.

Not flagged: judgment on meaning, tone, ambiguity or severity; persona; a one-off operation cheaper to say than to script; work the pre-pass already did.