---
name: whatis
description: "What Is This — explain anything as a picture-first HTML page. Use when the user types /whatis <topic>, or asks what something is / how it works and would be better served by big diagrams than by paragraphs."
---

# whatis

Explain like I'm someone who knows nothing about this topic, using an HTML page with big pictures and few words.

No Artifact tool in this environment: write a self-contained HTML file (inline SVG/CSS, no external deps) to a temp directory (e.g. `$TMPDIR` or `/tmp`), then `open` it.

If the current context is not enough to explain the topic, gather enough context yourself before drawing. Every node in a diagram must be backed by evidence; never fabricate.

Draw real diagrams in SVG, freely picking and combining whatever fits: flowchart, sequence diagram, state diagram, architecture/block diagram, C4, dependency graph, call graph, ER diagram, class diagram, DFD, swimlane, deployment diagram, timeline, Gantt, git graph, before/after comparison, bar/line chart, treemap, heatmap... If none fits, design your own — expression comes before templates. Tables are for enumerations only and don't count as diagrams.

A diagram exists to make structure visible: who talks to whom, what causes what, what changes when. Draw each one in the shape the reader's eye already knows — boxes for parts, arrows for actions, lanes for actors, time flowing one way. Make each diagram read at two distances: at a glance only the backbone shows — a name per box, a verb per arrow, one path the eye can follow; the detail lives in a quieter layer of smaller, dimmer annotations that never competes with the backbone. Color like a print magazine: warm paper background, ink for text and lines, one muted accent doing all the pointing; status reads from marks and line weight, tinted from the same palette. One diagram, one point: when the content outgrows the shape, split it or summarize the tail — shrinking the type is never the answer. The test: someone who reads only the diagrams and captions still gets the whole story.

Give the page a wide content column with visible margins on both sides: diagrams span the column (each SVG gets a viewBox and `width:100%` so it scales with the window), prose sits in a narrower measure within it.

Match the user's language in the explanation. Keep technical terms, API names, CLI commands, and exact error strings verbatim in English.