Lean body that assumes Claude knows what trends and queries are; the JSON example and prose each earn their place with no padding or basic-concept explanation.

The line case provides a complete, copy-paste TrendsQuery JSON; the slope case gives concrete guidance via the query-trends result-card toggle, which is appropriately instruction-based since the action is a UI affordance.

Clear decision sequence — detect ambiguity, clarify with an either/or, render the chosen chart — with an explicit 'skip the question and build it' shortcut when the user already named one. Not a destructive/batch task, so feedback loops are not required.

A self-contained body under the simple-skill threshold with well-organized sections and no claimed external references; no bundle files exist, so organization alone justifies the top score.

Names multiple concrete actions — 'Clarify how to visualize change', 'Ask which they want, then render it' — and distinguishes the two renderings ('a line, every interval' vs 'two endpoints (a slope)').

Explicitly answers both what ('Clarify how to visualize change... Ask which they want, then render it') and when ('Use whenever the user asks how much something changed...'), with an explicit exclusion.

Rich natural phrasing users would say: 'how much did X change from A to B', 'before vs after', 'start vs end', 'week over week', 'compare this month to last', 'change over time', 'slope chart'/'slopegraph'.

Narrow niche (line vs slope for time-range change) with distinct triggers and an explicit exclusion ('Not for choosing a saved insight ChartDisplayType') to avoid the wrong skill firing.