new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
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Observable Plot

Answer questions about Observable Plot as documented today: every mark and its channels, scales and their options, faceting, transforms such as bin, group, stack and window, legends and axes, projections, and how to compose a full figure — with the option names and defaults exact.

992 notes · updated 2026-08-10 · trained 76%

use this brain
# sign in to get a token
$ claude mcp add --transport http mozg \
https://mozg.sh/mcp --header "Authorization: Bearer …"
> use mozg/observable-plot — …
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Ask it things like

answers 30/40 on its latest exam
What channels do you use for small multiples faceting?Faceting & Layout✓
Which marks are incompatible with projections?Marks & Channels✓
What does Plot.plot() return?Rendering & API✓
What does the bin transform do and when would you use it?Transforms✓
What is the purpose of the group transform and how do you bind channels?Transforms✓
What does the facetAnchor option do?Faceting & Layout✓
What are the four margin layout options?Faceting & Layout✓
What data types are compatible with faceting?Faceting & Layout✓

What it can answer

40 coverage checks
76%
Answers 30 of the exam's 40 questions
✓Faceting & Layout6 / 6
▲Marks & Channels6 / 8
✓Projections4 / 4
▲Scales4 / 6
▲Transforms4 / 6
▲Legends & Axes3 / 4
▲Rendering & API3 / 4
✕Accessibility0 / 2
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Attacks survived

re-run weekly · 2026-08-10
✓gate-battery12/12 known hostile payloads caught by the ingest gate
✓injection-corpusevery active note scanned — no steering language
✓secret-corpusevery active note scanned — no keys or credentials

heuristic scans against known attack classes — measured and dated, not a promise of unpoisonability

Inside

  • Example: custom arealineY composite mark · marks
  • Plot transforms work automatically with faceting · transforms
  • Transforms are composable through options · transforms
  • Plot vs D3 trade-offs · plots
  • Plot minimizes chart creation time with defaults · plots
  • Plot includes built-in transforms for data aggregation · transforms
  • Bar mark applies implicit stack transform with fill encoding · marks
  • Custom composite marks via Plot.marks() · marks
  • Plot generates SVG for CSS styling and manipulation · plots
  • Plot builds on D3 implementations · plots
  • Observable Plot purpose and use case · plots
  • Plot.windowY() function · transforms
  • Plot.windowX() function · transforms
  • Window transform reduce option · transforms

Licence

CC BY-NC-SA 4.0

Use it, copy it, build on it, with credit. Selling it is not allowed.