Conciseness

The body is lean, assumes Claude's competence, and spends its tokens on genuinely useful scoping ('Interactive explorations with complex pan, zoom, or brush behaviours', 'Geographic visualisations with custom projections'). However, the Limitations bullet 'Use this skill only when the task clearly matches the scope described above' duplicates the preceding 'When to use d3.js' section, a minor trimmable instance — anchor 4, not 5's 'every token earns its place'.

Actionability

There is a concrete, verifiable pointer ('Read [the detailed guide](references/detailed-guide.md) before executing this skill') and specific selection criteria, but every executable step is deferred to the reference — the body itself contains no commands, code, or how-to steps. This matches 'some concrete guidance but incomplete', short of anchor 4's 'concrete code or commands with minor gaps'.

Workflow Clarity

A clear sequence is present: check the 'When to use' scope, read the guide (with focused vs. end-to-end loading guidance), and stop points exist ('Stop and ask for clarification if required inputs... are missing'). No destructive or batch operations are involved, so no cap applies; it falls short of anchor 5 only because execution checkpoints live entirely in the referenced guide rather than the body.

Progressive Disclosure

The body is a clear overview with a well-signaled, one-level-deep reference, and the referenced detailed-guide.md genuinely exists and indexes the remaining bundle files (d3-patterns.md, scale-reference.md, colour-schemes.md, chart-template.jsx, interactive-template.jsx, sample-data.json). It misses anchor 5 because the SKILL.md body itself provides no direct map to those files, so focused work (e.g., choosing a colour scheme) must load the full guide first.

Specificity

"creating sophisticated, interactive data visualisations using d3.js" names the domain and one action with the 'interactive' attribute, but 'sophisticated' is fluff and no concrete capabilities (e.g., force-directed graphs, custom projections) are enumerated. It matches the 'names domain and 1-2 concrete actions, but not comprehensive' anchor — above anchor 2 because an action beyond the bare domain is stated, below anchor 4 because only one generic action is listed.

Completeness

A 'what' is present ("provides guidance for creating... data visualisations using d3.js") but the description contains no 'Use when...' clause or equivalent trigger guidance, which caps completeness at 3. Not 4, because the 'when' is entirely absent rather than merely imprecise.

Trigger Term Quality

The only natural terms are "d3.js" and "data visualisations"; common variations users actually say — chart, graph, plot, dashboard — are all missing. This matches 'some relevant keywords but missing common variations or synonyms', not anchor 4 where only a few natural terms are absent.

Distinctiveness Conflict Risk

Naming d3.js explicitly carves a mostly distinct niche unlikely to trigger for unrelated skills, but the broad phrase "sophisticated, interactive data visualisations" overlaps generic charting/dataviz skills without disambiguating (e.g., 'custom or novel visualisations not available in standard chart libraries'). Minor overlap risk with closely related skills matches anchor 4, short of anchor 5's 'clear niche with distinct triggers'.