Conciseness

The body is dense and Max-specific throughout — it states preferences rather than explaining concepts Claude already knows, and the banned word/phrase lists are compact list-form with no padding. Minor trimmable redundancy keeps it below a 5: the mic-drop rule is fully explained in "Rhythm and structure" and then re-demonstrated with its own explanation in Example 5, the dash guidance recurs in Example 4's parenthetical, and there are flavor asides ("(Yes, even though he's British about most things...)").

Actionability

For an instruction-only skill this is maximally actionable: literal banned word and phrase lists that can be cut on sight ("delve, leverage (as a verb), utilize..."), five concrete before/after transformation pairs covering the common failure cases, an executable self-check ("read your first sentence. If deleting it loses nothing, delete it"), and per-context calibration with concrete examples ("Fix race condition in cache eviction").

Workflow Clarity

A simple single-task skill (apply these style rules whenever writing prose for Max) whose single action is unambiguous: a governing principle up front ("When in doubt, cut words and warm up the tone"), hard rules, then a "Calibration by context" section that sequences how the formality dial moves by output type. No destructive or batch operations exist, so the validation cap does not apply.

Progressive Disclosure

The single-file body is well organized with a logical section flow (voice → hard rules → banned → padding → marketing tone → rhythm → examples → calibration) and no buried content. However, the rubric's simple-skill carve-out (a 5 from well-organized sections alone) covers only skills under 50 lines with no need for external references; this body is roughly 95 lines, and the banned word/phrase lists and five worked examples are inlined where a one-level reference file could hold them to keep the core file lean.

Specificity

The description comprehensively enumerates concrete surfaces ("docs, READMEs, PR descriptions, commit messages, Slack, emails, code comments, error messages, blog posts, and replies in chat") and concrete style rules ("US English, sentence case, the Oxford comma, and zero AI jargon"), which is anchor-5 material. However, it is written in second person ("any prose you generate for him", "whenever you are writing or editing English prose"), which the judging guidelines explicitly penalize by reducing specificity by 1.

Completeness

Both what and when are explicit and concrete: the what names the house style and its specific rules, and the when is a multi-conditioned explicit trigger ("Use this whenever you are writing or editing English prose meant for Max or sent on his behalf, even when he doesn't explicitly ask for a particular style") plus a default-on clause and a negative boundary ("Do not use it for code itself, config, or data formats").

Trigger Term Quality

Natural trigger terms cover the domain comprehensively: "docs, READMEs, PR descriptions, commit messages, Slack, emails, code comments, error messages, blog posts" are exactly the words a user says when asking for prose, and "writing or editing English prose" plus "anything wordier than a one-line answer" catch the remainder. No meaningful natural terms are missing for a prose-style skill.

Distinctiveness Conflict Risk

"Max's house writing style" is a clear personal niche with distinct triggers, and the explicit exclusions for code, config, and data formats preclude overlap with adjacent skills. A request to write prose for Max is unambiguous.