Lens: leanness

Lane: whether every line beats its own absence, and whether what survives is a goal. The bar is canon.md, applied line by line; cite its tests, do not restate them.

• Core-test failures: lines a capable model follows unprompted. "Make sure", "don't forget", templates that teach markdown, mechanics of a tool the model drives fluently, scoring formulas for judgment. Low for a line or two, high for a section.
• Explanation wrapped around an instruction that survives truncation: low or medium.
• Meta-explanation of the system to itself, negative space ("this no longer does"), facts restated across sections: medium.
• Numbered lists that are not sequences: independent steps the model will march through. Medium; the recommendation holds the goal sentence that replaces them. A sequence guarding a named failure stays.
• ALL-CAPS MUST, ALWAYS, NEVER and stacked imperatives: medium; recommend the failure the rule prevents, in plain words.
• A stripped why: a non-obvious rule with no reason, so it cannot reach the unforeseen case. Medium; under-writing, not leanness.
• The same point in two places: medium; name the one place it belongs. A step that ends on a bound the model cannot check ("when it is clear", "once done"): medium; recommend the condition that closes it.
• A prohibition where a positive form says the same, or a coined term and adjective runs where one word the model knows would do: low; recommend the positive sentence or the word.
• Content the model could get by looking, a file's contents, a command's flags, copied into the skill: low, since it goes stale.
• A worked artifact where a format line would do: medium; recommend the line, or a pointer to the project's own instances, per test 8 in canon.md.
• A section that cannot name where its elaborate form beats a five-line version (role, outcome, consumer, the scarred rules): write the five lines into proposed_smallest and the predicted loss, often nothing, into predicted_delta; ship.md and modes/cut.md apply it, and a variant eval through the bmad-eval skill measures it when the user doubts the cut. High for a section, medium for a paragraph.

Not flagged: persona voice in an agent (identity, communication style, principles, examples of voice): the bar applies to capability prompts, and a flatter persona is a worse outcome, not a leaner one; repetition or contradiction inside persona text still counts. A menu item whose prompt is a sentence with no capability file: it is listed for the user to see what is on offer, and the model does the rest. The other lenses' lanes. Critical only for friction that misleads the model into a wrong action.