CtrlK
BlogDocsLog inGet started
Tessl Logo

visualizing-change-over-time

Helps PostHog engineers and agents pick the right chart when a request is about visualizing change over time, before/after comparisons, or period-over-period movement while building UI with @posthog/quill-charts (dashboards, reports, the mcp_analytics frontend, custom visualizations). Use when a user asks how something "changed", "moved", "grew", "dropped", "improved", or "regressed" between two points or periods, or mentions "before/after", "period over period", "week over week", "delta", "slope graph", "slopegraph", or comparing many series across two snapshots. Surfaces both the `SlopeChart` quill component and the native `ChartDisplayType.SlopeGraph` insight display as options.

71

Quality

87%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide

SecuritybySnyk

—

The risk profile of this skill

SKILL.md
Quality
Evals
Security

Quality

Content

75%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A well-structured, actionable body: a decision table, an executable example, key options, and a scope note, with lean references one level deep. It lands just under the top anchor across the board due to minor verbosity and deferred detail.

Suggestions

Tighten the 'Scope note' into a short two-bullet contrast (SlopeChart component vs ChartDisplayType.SlopeGraph insight) and move the backend-runner/API specifics behind the existing docs link to improve conciseness.

Show the minimal theme wiring (useChartTheme()) and required wrapper height inline so the SlopeChart example is fully runnable without following a link.

Turn the SlopeChart-vs-SlopeGraph decision into a small table mirroring the shape picker so the surface choice reads as a crisp sequence rather than prose.

DimensionReasoningScore

Conciseness

Mostly lean and assumes competence, but the prose intro and the detailed 'Scope note' (backend runner paths, API/MCP usage) could be trimmed — minor instances of over-explanation rather than the perfectly lean top anchor.

4 / 5

Actionability

Copy-paste-ready TSX example with real imports, series shape, and config props plus a shape-to-component decision table; minor gaps since theme wiring and sizing are deferred to AGENTS.md rather than shown.

4 / 5

Workflow Clarity

The 'Pick by the shape of the change' table plus 'let the user choose' gives a clear selection sequence with no risky/batch ops needing validation; falls just short of the top anchor because the SlopeChart-vs-SlopeGraph choice is explained in a prose scope note rather than a crisp step list.

4 / 5

Progressive Disclosure

Good section structure with clearly signaled one-level-deep references (charts AGENTS.md, docs/chart-types.md); no bundle files exist to demonstrate a fuller split, keeping it just below the top anchor.

4 / 5

Total

16

/

20

Passed

Description

100%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

An excellent description: concrete, comprehensive trigger coverage, explicit what-and-when, and a clearly distinct niche with third-person voice. It hits the top anchor on every dimension.

DimensionReasoningScore

Specificity

Names the domain and lists multiple concrete actions/surfaces — 'pick the right chart', 'Surfaces both the `SlopeChart` quill component and the native `ChartDisplayType.SlopeGraph` insight display' — giving comprehensive coverage within its niche.

5 / 5

Completeness

Explicitly answers 'what' (chart selection for change-over-time; surfaces SlopeChart and SlopeGraph) and 'when' via a concrete 'Use when...' clause with specific trigger phrases.

5 / 5

Trigger Term Quality

Comprehensive natural trigger terms a user would actually say — 'changed', 'moved', 'grew', 'dropped', 'improved', 'regressed', 'before/after', 'period over period', 'week over week', 'delta', 'slope graph', 'slopegraph' — including synonyms.

5 / 5

Distinctiveness Conflict Risk

Clear niche (slope graphs / change-over-time chart selection within @posthog/quill-charts) with distinct triggers and minimal overlap risk; written in third person ('Helps', 'Surfaces').

5 / 5

Total

20

/

20

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

relative_links

Relative link issues: 2 suspicious

Warning

Total

15

/

16

Passed

Repository
PostHog/posthog
Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.