diff --git a/plots/choropleth-basic/implementations/javascript/chartjs.js b/plots/choropleth-basic/implementations/javascript/chartjs.js
new file mode 100644
index 0000000000..9dee29a8d3
--- /dev/null
+++ b/plots/choropleth-basic/implementations/javascript/chartjs.js
@@ -0,0 +1,258 @@
+// anyplot.ai
+// choropleth-basic: Choropleth Map with Regional Coloring
+// Library: chartjs 4.4.7 | JavaScript 22.23.2
+// Quality: 85/100 | Created: 2026-09-02
+
+// Chart.js has no built-in geographic/shape geometry (that lives only in the
+// chartjs-chart-geo plugin, which is not installed in this runtime — see
+// prompts/library/chartjs.md "No Workarounds"). This renders the same
+// region -> value story as a tile map: one square per region, positioned by
+// its real-world longitude/latitude, colored on the Imprint sequential scale.
+// Region "boundaries" are the square's stroke; missing data renders as a
+// muted gray tile, per the specification's data-handling note.
+const t = window.ANYPLOT_TOKENS;
+const MUTED = t.theme === "dark" ? "#A8A79F" : "#6B6A63";
+
+// --- Data (in-memory, deterministic) ----------------------------------------
+// Renewable share of electricity generation (%) by country, with approximate
+// centroid coordinates. Two countries carry no reading to demonstrate the
+// missing-data handling the spec calls for.
+const countries = [
+  { code: "CA", lon: -106.3, lat: 56.1, value: 68 },
+  { code: "US", lon: -95.7, lat: 37.1, value: 21 },
+  { code: "MX", lon: -102.6, lat: 23.6, value: 24 },
+  { code: "BR", lon: -51.9, lat: -14.2, value: 84 },
+  { code: "AR", lon: -63.6, lat: -38.4, value: 33 },
+  { code: "CO", lon: -74.1, lat: 4.6, value: 70 },
+  { code: "PE", lon: -75.2, lat: -9.2, value: 60 },
+  { code: "CL", lon: -71.5, lat: -35.7, value: 46 },
+  { code: "GB", lon: -3.4, lat: 55.4, value: 43 },
+  { code: "FR", lon: 2.2, lat: 46.6, value: 27 },
+  { code: "DE", lon: 10.5, lat: 51.2, value: 46 },
+  { code: "ES", lon: -3.7, lat: 40.5, value: 50 },
+  { code: "IT", lon: 12.6, lat: 41.9, value: 41 },
+  { code: "NO", lon: 8.5, lat: 60.5, value: 98 },
+  { code: "SE", lon: 18.6, lat: 60.1, value: 68 },
+  { code: "PL", lon: 19.1, lat: 51.9, value: 17 },
+  { code: "RU", lon: 105.3, lat: 61.5, value: 20 },
+  { code: "TR", lon: 35.2, lat: 38.9, value: 44 },
+  { code: "EG", lon: 30.8, lat: 26.8, value: 12 },
+  { code: "NG", lon: 8.7, lat: 9.1, value: null },
+  { code: "ZA", lon: 22.9, lat: -30.6, value: 9 },
+  { code: "KE", lon: 37.9, lat: -0.0, value: 90 },
+  { code: "MA", lon: -7.1, lat: 31.8, value: 20 },
+  { code: "SA", lon: 45.1, lat: 23.9, value: 1 },
+  { code: "IN", lon: 78.9, lat: 20.6, value: 23 },
+  { code: "CN", lon: 104.1, lat: 35.9, value: 31 },
+  { code: "JP", lon: 138.3, lat: 36.2, value: 22 },
+  { code: "KR", lon: 127.8, lat: 35.9, value: 9 },
+  { code: "ID", lon: 113.9, lat: -0.8, value: null },
+  { code: "TH", lon: 100.9, lat: 15.9, value: 18 },
+  { code: "VN", lon: 108.8, lat: 14.1, value: 40 },
+  { code: "AU", lon: 133.8, lat: -25.3, value: 32 },
+  { code: "NZ", lon: 174.9, lat: -40.9, value: 87 },
+];
+
+// --- Imprint sequential scale (green -> blue), binned for a readable legend
+const hexToRgb = (hex) => ({
+  r: parseInt(hex.slice(1, 3), 16),
+  g: parseInt(hex.slice(3, 5), 16),
+  b: parseInt(hex.slice(5, 7), 16),
+});
+const lerp = (a, b, f) => Math.round(a + (b - a) * f);
+const seqRgb = (frac) => {
+  const c0 = hexToRgb(t.seq[0]);
+  const c1 = hexToRgb(t.seq[1]);
+  return { r: lerp(c0.r, c1.r, frac), g: lerp(c0.g, c1.g, frac), b: lerp(c0.b, c1.b, frac) };
+};
+const toCss = ({ r, g, b }) => `rgb(${r}, ${g}, ${b})`;
+// WCAG-ish relative luminance so a code label always reads against its own tile,
+// regardless of theme (tile fill colors are identical across themes).
+const luminance = ({ r, g, b }) => 0.299 * r + 0.587 * g + 0.114 * b;
+const LABEL_LIGHT = "#FFFDF6";
+const LABEL_DARK = "#1A1A17";
+
+const bins = [
+  { label: "< 10%", max: 10 },
+  { label: "10–25%", max: 25 },
+  { label: "25–40%", max: 40 },
+  { label: "40–65%", max: 65 },
+  { label: "≥ 65%", max: Infinity },
+].map((bin, i, arr) => {
+  // Highest-renewable bins read as brand green, lowest as blue, so the color
+  // story matches the metric (more green = more renewable).
+  const rgb = seqRgb(1 - i / (arr.length - 1));
+  return { ...bin, color: toCss(rgb), textColor: luminance(rgb) > 140 ? LABEL_DARK : LABEL_LIGHT };
+});
+
+const binIndex = (value) => bins.findIndex((bin) => value <= bin.max);
+const mutedTextColor = luminance(hexToRgb(MUTED)) > 140 ? LABEL_DARK : LABEL_LIGHT;
+
+// --- Basemap -----------------------------------------------------------------
+// Chart.js core has no polygon-fill geometry, so this draws a lightweight
+// continent-outline graticule (stroked line datasets, no fill) behind the
+// tiles purely for geographic orientation — it is not a projected basemap.
+const CONTINENTS = [
+  [
+    [-125, 49], [-95, 78], [-75, 68], [-60, 50], [-52, 47], [-65, 44],
+    [-75, 35], [-80, 26], [-97, 26], [-90, 15], [-105, 20], [-115, 29], [-125, 49],
+  ],
+  [
+    [-77, 10], [-60, 10], [-50, 0], [-35, -5], [-40, -20], [-48, -25],
+    [-58, -34], [-68, -47], [-72, -40], [-70, -20], [-79, -5], [-77, 10],
+  ],
+  [
+    [-17, 15], [0, 5], [10, 4], [15, -5], [13, -18], [18, -34], [30, -30],
+    [40, -15], [42, 0], [45, 10], [38, 15], [33, 31], [10, 37], [-17, 15],
+  ],
+  [
+    [-9, 43], [0, 50], [10, 54], [20, 55], [30, 60], [40, 65], [30, 45],
+    [20, 40], [10, 38], [-5, 36], [-9, 43],
+  ],
+  [
+    [26, 40], [40, 45], [60, 55], [80, 55], [100, 50], [120, 50], [140, 55],
+    [145, 45], [130, 35], [120, 25], [105, 10], [95, 5], [80, 10], [70, 20],
+    [60, 25], [50, 30], [35, 30], [26, 40],
+  ],
+  [
+    [113, -22], [122, -18], [135, -12], [145, -16], [153, -28], [150, -38],
+    [140, -38], [130, -32], [115, -34], [113, -22],
+  ],
+];
+const basemapDatasets = CONTINENTS.map((outline, i) => ({
+  type: "line",
+  label: `basemap-${i}`,
+  skipLegend: true,
+  data: outline.map(([lon, lat]) => ({ x: lon, y: lat })),
+  borderColor: t.grid,
+  backgroundColor: "transparent",
+  borderWidth: 1.5,
+  pointRadius: 0,
+  pointHoverRadius: 0,
+  fill: false,
+  tension: 0,
+}));
+
+// --- Mount -------------------------------------------------------------------
+const canvas = document.createElement("canvas");
+document.getElementById("container").appendChild(canvas);
+
+// A tile-map has no room for chartjs-chart-geo's boundary shapes (not
+// installed — see prompts/library/chartjs.md), so region codes are drawn
+// directly onto each square with a plain Chart.js plugin (native canvas
+// access, no external package) instead.
+const regionLabelPlugin = {
+  id: "regionLabels",
+  afterDatasetsDraw(chart) {
+    const { ctx } = chart;
+    chart.data.datasets.forEach((dataset, dsIndex) => {
+      if (dataset.skipLegend) return; // basemap outline, not a data tile
+      const meta = chart.getDatasetMeta(dsIndex);
+      meta.data.forEach((point, i) => {
+        const raw = dataset.data[i];
+        ctx.save();
+        ctx.font = "600 12px -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif";
+        ctx.fillStyle = dataset.textColor;
+        ctx.textAlign = "center";
+        ctx.textBaseline = "middle";
+        ctx.fillText(raw.code, point.x, point.y);
+        ctx.restore();
+      });
+    });
+  },
+};
+
+// --- Chart ---------------------------------------------------------------
+const datasets = bins.map((bin, i) => ({
+  label: `${bin.label} renewable`,
+  data: countries.filter((c) => c.value !== null && binIndex(c.value) === i),
+  backgroundColor: bin.color,
+  textColor: bin.textColor,
+  borderColor: t.ink,
+  borderWidth: 1.5,
+  pointStyle: "rect",
+  pointRadius: 20,
+  pointHoverRadius: 22,
+}));
+datasets.push({
+  label: "No data",
+  data: countries.filter((c) => c.value === null),
+  backgroundColor: MUTED,
+  textColor: mutedTextColor,
+  borderColor: t.ink,
+  borderWidth: 1.5,
+  pointStyle: "rect",
+  pointRadius: 20,
+  pointHoverRadius: 22,
+});
+
+const title = "Renewable Electricity Share · choropleth-basic · javascript · chartjs · anyplot.ai";
+const titleFontSize = Math.round(22 * Math.min(1, 67 / title.length));
+
+new Chart(canvas, {
+  type: "scatter",
+  data: {
+    // Basemap outlines first so tile squares draw on top of them.
+    datasets: [
+      ...basemapDatasets,
+      ...datasets.map((d) => ({
+        ...d,
+        data: d.data.map((c) => ({ x: c.lon, y: c.lat, code: c.code, value: c.value })),
+      })),
+    ],
+  },
+  plugins: [regionLabelPlugin],
+  options: {
+    responsive: true,
+    maintainAspectRatio: false,
+    animation: false,
+    layout: { padding: { top: 8, bottom: 8, left: 16, right: 16 } },
+    plugins: {
+      title: { display: true, text: title, color: t.ink, font: { size: titleFontSize, weight: "500" } },
+      legend: {
+        position: "bottom",
+        labels: {
+          color: t.inkSoft,
+          font: { size: 16 },
+          boxWidth: 22,
+          boxHeight: 22,
+          padding: 18,
+          filter: (item, data) => !data.datasets[item.datasetIndex].skipLegend,
+        },
+      },
+      tooltip: {
+        filter: (item) => !item.dataset.skipLegend,
+        callbacks: {
+          title: () => "",
+          label: (ctx) =>
+            ctx.raw.value === null || ctx.raw.value === undefined
+              ? `${ctx.raw.code}: no data`
+              : `${ctx.raw.code}: ${ctx.raw.value}% renewable`,
+        },
+      },
+    },
+    scales: {
+      // Tightened to the real longitude/latitude extent of the 32 countries
+      // (plus a small margin) rather than the full -180..180/-90..90 globe,
+      // so the canvas isn't dominated by empty ocean.
+      x: {
+        type: "linear",
+        min: -118,
+        max: 182,
+        display: true,
+        border: { display: false },
+        ticks: { display: false },
+        grid: { display: false },
+      },
+      y: {
+        type: "linear",
+        min: -48,
+        max: 68,
+        display: true,
+        border: { display: false },
+        ticks: { display: false },
+        grid: { display: false },
+      },
+    },
+  },
+});
diff --git a/plots/choropleth-basic/metadata/javascript/chartjs.yaml b/plots/choropleth-basic/metadata/javascript/chartjs.yaml
new file mode 100644
index 0000000000..95f558a7d6
--- /dev/null
+++ b/plots/choropleth-basic/metadata/javascript/chartjs.yaml
@@ -0,0 +1,251 @@
+library: chartjs
+language: javascript
+specification_id: choropleth-basic
+created: '2026-09-02T15:42:50Z'
+updated: '2026-09-02T16:01:26Z'
+generated_by: claude-sonnet
+workflow_run: 33647965470
+issue: 3069
+language_version: 22.23.2
+library_version: 4.4.7
+preview_url_light: https://storage.googleapis.com/anyplot-images/plots/choropleth-basic/javascript/chartjs/plot-light.png
+preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/choropleth-basic/javascript/chartjs/plot-dark.png
+preview_html_light: https://storage.googleapis.com/anyplot-images/plots/choropleth-basic/javascript/chartjs/plot-light.html
+preview_html_dark: https://storage.googleapis.com/anyplot-images/plots/choropleth-basic/javascript/chartjs/plot-dark.html
+quality_score: 85
+review:
+  strengths:
+  - 'All three attempt-1 weaknesses were addressed directly: continent-outline basemap
+    adds geographic context, sequential color direction now runs green-for-high, and
+    axis bounds are tightened to the real data extent'
+  - 'Excellent theme-adaptive rendering: data tile colors are pixel-identical between
+    light and dark renders, while chrome correctly flips with no dark-on-dark or light-on-light
+    failures'
+  - Highly realistic, factually accurate renewable-electricity-share data for 32 countries
+    spanning every continent
+  - Honest, well-documented handling of Chart.js's lack of native geo/polygon support
+    - no chartjs-chart-geo plugin, no fake interactivity
+  - 'Missing-data handling implemented exactly per spec: two countries render as muted
+    gray No data tiles with a dedicated legend entry'
+  - Per-tile text color chosen via luminance check so every country code stays legible
+    regardless of the underlying fill color
+  weaknesses:
+  - 'SC-01/SC-02: Still not a literal choropleth - no filled region polygons or map
+    projection, though this is a genuine Chart.js core limitation and the basemap
+    is the right compensating move'
+  - 'CQ-01: The half-dozen small helper functions (hexToRgb, lerp, seqRgb, toCss,
+    luminance, binIndex) push slightly past pure KISS, though each is justified by
+    the binned-continuous-scale requirement'
+  - Continent outlines are stylized/approximate rather than accurate coastlines -
+    acceptable given the constraints, but worth noting as a simplification
+  image_description: |-
+    Light render (plot-light.png):
+      Background: Warm off-white, matches #FAF8F1, not pure white.
+      Chrome: Title "Renewable Electricity Share · choropleth-basic · javascript · chartjs · anyplot.ai" in dark ink, centered top, clearly legible. Bottom legend with six horizontal swatches and dark-ink labels, all readable. A lightweight continent-outline graticule (thin gray strokes, no fill) sits behind the tiles for geographic context.
+      Data: 32 country tiles (square markers) positioned by longitude/latitude, filled with the Imprint sequential scale (imprint_seq) binned into 5 buckets. Direction is correct: high-renewable countries (Norway, Brazil, Colombia, Kenya, New Zealand) render brand green #009E73; low-renewable countries (Saudi Arabia, South Africa, South Korea) render blue. 2 muted-gray "No data" tiles (NG, ID) with a dedicated legend entry. Each tile carries a legible 2-letter country code.
+      Legibility verdict: PASS
+
+    Dark render (plot-dark.png):
+      Background: Warm near-black, matches #1A1A17, not pure black.
+      Chrome: Title and legend render in light ink, clearly visible. Continent outlines remain visible (stroked in the theme's grid color) against the dark background.
+      Data: Tile fill colors are pixel-identical to the light render - confirmed, only chrome flipped. In-tile country-code text colors remain legible per-tile via luminance-based logic; no dark-on-dark failures on any tile, including the muted-gray "No data" tiles.
+      Legibility verdict: PASS
+  criteria_checklist:
+    visual_quality:
+      score: 27
+      max: 30
+      items:
+      - id: VQ-01
+        name: Text Legibility
+        score: 6
+        max: 8
+        passed: true
+        comment: Title scales with length and is clearly legible; legend at 16px;
+          in-tile 12px country codes are small but legible in both themes
+      - id: VQ-02
+        name: No Overlap
+        score: 6
+        max: 6
+        passed: true
+        comment: No overlapping tiles, labels, legend entries, or basemap strokes
+      - id: VQ-03
+        name: Element Visibility
+        score: 5
+        max: 6
+        passed: true
+        comment: Uniform 20px-radius tiles clearly visible for 32 points; size doesn't
+          vary with value
+      - id: VQ-04
+        name: Color Accessibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Luminance-based per-tile text color plus redundant country-code labels
+          avoid hue-only signaling
+      - id: VQ-05
+        name: Layout & Canvas
+        score: 4
+        max: 4
+        passed: true
+        comment: Axis bounds now tightened to the real data extent, removing excess
+          margin flagged in attempt 1
+      - id: VQ-06
+        name: Axis Labels & Title
+        score: 2
+        max: 2
+        passed: true
+        comment: Cartesian axes intentionally unlabeled for map style; legend carries
+          descriptive labels
+      - id: VQ-07
+        name: Palette Compliance
+        score: 2
+        max: 2
+        passed: true
+        comment: Built from imprint_seq, direction now correct (green = high); identical
+          data colors across themes
+    design_excellence:
+      score: 15
+      max: 20
+      items:
+      - id: DE-01
+        name: Aesthetic Sophistication
+        score: 5
+        max: 8
+        passed: true
+        comment: Continent-outline basemap meaningfully improves polish; still a positioned-tile
+          map, not a filled-region choropleth
+      - id: DE-02
+        name: Visual Refinement
+        score: 5
+        max: 6
+        passed: true
+        comment: Basemap strokes read as a map graticule; tiles remain crisply edge-highlighted
+      - id: DE-03
+        name: Data Storytelling
+        score: 5
+        max: 6
+        passed: true
+        comment: Green-for-high/blue-for-low now matches reader intuition; geographic
+          layout creates clear narrative
+    spec_compliance:
+      score: 12
+      max: 15
+      items:
+      - id: SC-01
+        name: Plot Type
+        score: 3
+        max: 5
+        passed: true
+        comment: Not a true choropleth (no filled polygons), but the continent-outline
+          basemap closes the gap given Chart.js core's limitations
+      - id: SC-02
+        name: Required Features
+        score: 3
+        max: 4
+        passed: true
+        comment: Legend, missing-data handling, and geographic basemap context present;
+          no real map projection or region boundaries
+      - id: SC-03
+        name: Data Mapping
+        score: 3
+        max: 3
+        passed: true
+        comment: X=longitude, Y=latitude, color=value; all 32 points correctly visible
+      - id: SC-04
+        name: Title & Legend
+        score: 3
+        max: 3
+        passed: true
+        comment: Title format correct; legend labels correctly describe bins + no-data
+    data_quality:
+      score: 15
+      max: 15
+      items:
+      - id: DQ-01
+        name: Feature Coverage
+        score: 6
+        max: 6
+        passed: true
+        comment: Full 1%-98% range, all continents represented, includes missing data
+      - id: DQ-02
+        name: Realistic Context
+        score: 5
+        max: 5
+        passed: true
+        comment: Renewable electricity share is a real, neutral, comprehensible scenario
+      - id: DQ-03
+        name: Appropriate Scale
+        score: 4
+        max: 4
+        passed: true
+        comment: Values closely track real-world figures (Norway 98%, Brazil 84%,
+          Saudi Arabia 1%, South Korea 9%)
+    code_quality:
+      score: 9
+      max: 10
+      items:
+      - id: CQ-01
+        name: KISS Structure
+        score: 2
+        max: 3
+        passed: true
+        comment: Mostly linear flow, but several small helper functions for the binned
+          continuous scale and basemap
+      - id: CQ-02
+        name: Reproducibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Fully deterministic hardcoded data
+      - id: CQ-03
+        name: Clean Imports
+        score: 2
+        max: 2
+        passed: true
+        comment: No unused imports
+      - id: CQ-04
+        name: Code Elegance
+        score: 2
+        max: 2
+        passed: true
+        comment: Appropriately complex, no fake functionality
+      - id: CQ-05
+        name: Output & API
+        score: 1
+        max: 1
+        passed: true
+        comment: Follows the mount-node contract correctly
+    library_mastery:
+      score: 7
+      max: 10
+      items:
+      - id: LM-01
+        name: Idiomatic Usage
+        score: 4
+        max: 5
+        passed: true
+        comment: Per-bin datasets for automatic legend, tooltip callbacks, documented
+          plugin lifecycle hook
+      - id: LM-02
+        name: Distinctive Features
+        score: 3
+        max: 5
+        passed: false
+        comment: Custom plugin for label drawing plus line-dataset basemap is Chart.js-specific
+          composition, though tile-map substitution itself isn't unique to the library
+  verdict: APPROVED
+impl_tags:
+  dependencies: []
+  techniques:
+  - colorbar
+  - annotations
+  - custom-legend
+  patterns:
+  - data-generation
+  - iteration-over-groups
+  dataprep:
+  - binning
+  styling:
+  - custom-colormap
+  - edge-highlighting
+  - publication-ready