diff --git a/plots/residual-plot/implementations/javascript/chartjs.js b/plots/residual-plot/implementations/javascript/chartjs.js
new file mode 100644
index 0000000000..f03b22137b
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+++ b/plots/residual-plot/implementations/javascript/chartjs.js
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+// anyplot.ai
+// residual-plot: Residual Plot
+// Library: chartjs 4.4.7 | JavaScript 22.23.2
+// Quality: 94/100 | Created: 2026-09-05
+
+const t = window.ANYPLOT_TOKENS;
+
+// --- Data (in-memory, deterministic LCG) ------------------------------------
+// Simulated linear-regression diagnostics: fitted house-price predictions
+// (in $1000s) vs. residuals, with mild heteroscedasticity (variance grows
+// with fitted value) so the fan-out pattern is visible.
+let seed = 42;
+function lcg() {
+  seed = (seed * 1664525 + 1013904223) % 4294967296;
+  return seed / 4294967296;
+}
+function gaussian() {
+  const u1 = 1 - lcg();
+  const u2 = lcg();
+  return Math.sqrt(-2 * Math.log(u1)) * Math.cos(2 * Math.PI * u2);
+}
+function hexToRgba(hex, alpha) {
+  const h = hex.replace("#", "");
+  const r = parseInt(h.substring(0, 2), 16);
+  const g = parseInt(h.substring(2, 4), 16);
+  const b = parseInt(h.substring(4, 6), 16);
+  return `rgba(${r}, ${g}, ${b}, ${alpha})`;
+}
+
+const n = 220;
+const fitted = [];
+const residuals = [];
+for (let i = 0; i < n; i++) {
+  const value = 150 + lcg() * 450; // fitted price, $150k-$600k
+  const noiseScale = 8 + (value - 150) * 0.05; // heteroscedastic spread
+  fitted.push(value);
+  residuals.push(gaussian() * noiseScale);
+}
+
+const mean = residuals.reduce((a, b) => a + b, 0) / n;
+const variance = residuals.reduce((a, b) => a + (b - mean) ** 2, 0) / n;
+const stdDev = Math.sqrt(variance);
+const threshold = 2 * stdDev;
+
+const normalPoints = [];
+const outlierPoints = [];
+for (let i = 0; i < n; i++) {
+  const point = { x: fitted[i], y: residuals[i] };
+  if (Math.abs(residuals[i]) > threshold) {
+    outlierPoints.push(point);
+  } else {
+    normalPoints.push(point);
+  }
+}
+
+const xMin = Math.min(...fitted);
+const xMax = Math.max(...fitted);
+
+// Rolling-mean smoothing trend (sorted by fitted value) to surface any
+// residual non-linearity — optional per spec, adds diagnostic value.
+const sortedIdx = fitted.map((_, i) => i).sort((a, b) => fitted[a] - fitted[b]);
+const sortedX = sortedIdx.map((i) => fitted[i]);
+const sortedY = sortedIdx.map((i) => residuals[i]);
+const windowSize = Math.max(15, Math.round(n * 0.12));
+const trendPoints = sortedX.map((x, i) => {
+  const lo = Math.max(0, i - Math.floor(windowSize / 2));
+  const hi = Math.min(n, i + Math.ceil(windowSize / 2));
+  const slice = sortedY.slice(lo, hi);
+  const avg = slice.reduce((a, b) => a + b, 0) / slice.length;
+  return { x, y: avg };
+});
+
+// --- Mount -------------------------------------------------------------------
+const canvas = document.createElement("canvas");
+document.getElementById("container").appendChild(canvas);
+
+// --- Chart ---------------------------------------------------------------------
+new Chart(canvas, {
+  type: "scatter",
+  data: {
+    datasets: [
+      {
+        label: "±2σ band",
+        data: [
+          { x: xMin, y: threshold },
+          { x: xMax, y: threshold },
+        ],
+        showLine: true,
+        borderColor: t.amber,
+        borderWidth: 1.5,
+        borderDash: [6, 4],
+        pointRadius: 0,
+        fill: "+2",
+        backgroundColor:
+          t.pageBg === "#1A1A17" ? "rgba(240,239,232,0.06)" : "rgba(26,26,23,0.04)",
+      },
+      {
+        label: "Zero reference",
+        data: [
+          { x: xMin, y: 0 },
+          { x: xMax, y: 0 },
+        ],
+        showLine: true,
+        borderColor: t.ink,
+        borderWidth: 2,
+        pointRadius: 0,
+      },
+      {
+        label: "−2σ band",
+        data: [
+          { x: xMin, y: -threshold },
+          { x: xMax, y: -threshold },
+        ],
+        showLine: true,
+        borderColor: t.amber,
+        borderWidth: 1.5,
+        borderDash: [6, 4],
+        pointRadius: 0,
+      },
+      {
+        label: "Residuals",
+        data: normalPoints,
+        backgroundColor: hexToRgba(t.palette[0], 0.7),
+        borderColor: t.pageBg,
+        borderWidth: 1,
+        pointRadius: 6,
+        pointHoverRadius: 7,
+      },
+      {
+        label: "Smoothed trend",
+        data: trendPoints,
+        showLine: true,
+        borderColor: t.palette[1],
+        borderWidth: 2,
+        borderDash: [3, 3],
+        pointRadius: 0,
+        fill: false,
+        tension: 0.3,
+      },
+      {
+        label: "Outliers (>2σ)",
+        data: outlierPoints,
+        backgroundColor: t.palette[4],
+        borderColor: t.pageBg,
+        borderWidth: 1,
+        pointRadius: 7,
+        pointStyle: "triangle",
+        pointHoverRadius: 8,
+      },
+    ],
+  },
+  options: {
+    responsive: true,
+    maintainAspectRatio: false,
+    animation: false,
+    plugins: {
+      title: {
+        display: true,
+        text: "residual-plot · javascript · chartjs · anyplot.ai",
+        color: t.ink,
+        font: { size: 22, weight: "500" },
+        padding: { bottom: 20 },
+      },
+      legend: {
+        labels: {
+          color: t.inkSoft,
+          font: { size: 14 },
+          filter: (item) => item.text !== "±2σ band" && item.text !== "−2σ band",
+        },
+      },
+      tooltip: { enabled: false },
+    },
+    scales: {
+      x: {
+        type: "linear",
+        title: { display: true, text: "Fitted Value ($1,000s)", color: t.ink, font: { size: 16 } },
+        ticks: { color: t.inkSoft, font: { size: 14 } },
+        grid: { color: t.grid },
+        border: { color: t.inkSoft },
+      },
+      y: {
+        title: { display: true, text: "Residual ($1,000s)", color: t.ink, font: { size: 16 } },
+        ticks: { color: t.inkSoft, font: { size: 14 } },
+        grid: { color: t.grid },
+        border: { color: t.inkSoft },
+      },
+    },
+  },
+});
diff --git a/plots/residual-plot/metadata/javascript/chartjs.yaml b/plots/residual-plot/metadata/javascript/chartjs.yaml
new file mode 100644
index 0000000000..9cf786bb15
--- /dev/null
+++ b/plots/residual-plot/metadata/javascript/chartjs.yaml
@@ -0,0 +1,250 @@
+library: chartjs
+language: javascript
+specification_id: residual-plot
+created: '2026-09-05T12:23:57Z'
+updated: '2026-09-05T12:37:47Z'
+generated_by: claude-sonnet
+workflow_run: 33965741710
+issue: 2332
+language_version: 22.23.2
+library_version: 4.4.7
+preview_url_light: https://storage.googleapis.com/anyplot-images/plots/residual-plot/javascript/chartjs/plot-light.png
+preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/residual-plot/javascript/chartjs/plot-dark.png
+preview_html_light: https://storage.googleapis.com/anyplot-images/plots/residual-plot/javascript/chartjs/plot-light.html
+preview_html_dark: https://storage.googleapis.com/anyplot-images/plots/residual-plot/javascript/chartjs/plot-dark.html
+quality_score: 94
+review:
+  strengths:
+  - 'Addressed both attempt-1 weaknesses directly: added alpha transparency (rgba
+    palette[0] at 0.7) on residual markers to soften overlapping clusters, and added
+    a rolling-mean smoothed trend line to surface non-linear patterns in the residuals'
+  - 'Correct semantic palette usage: brand green (palette[0]) for the main residual
+    series, matte-red (palette[4]) AND a triangle marker shape for outliers (redundant,
+    CVD-safe encoding), amber anchor for the ±2σ threshold lines'
+  - 'Theme-adaptive ±2σ band shading: the relative-fill overlay tint flips (dark tint
+    on light bg, light tint on dark bg) so the shaded region stays subtly visible
+    in both themes instead of a single hardcoded color'
+  - Deterministic LCG + Box-Muller-style gaussian data generation with realistic heteroscedastic
+    house-price regression scenario (variance grows with fitted value)
+  - 'Idiomatic Chart.js technique mix: relative `fill: "+2"` dataset-index trick for
+    the band, `legend.filter` callback to suppress duplicate band-line legend entries,
+    mixed scatter+line datasets'
+  weaknesses:
+  - A few marker clusters (e.g. near fitted≈250, fitted≈560) still touch slightly
+    even with alpha=0.7 — a marginally lower alpha or smaller point radius in dense
+    regions would separate them further
+  - The two ±2σ threshold lines are filtered out of the legend entirely rather than
+    merged into one labeled entry — a first-time viewer has no textual cue for what
+    the dashed amber lines represent
+  - Visual refinement is professional but not distinctive beyond the functional band/outlier/trend
+    treatments — no standout design flourish beyond what's functionally required
+  image_description: |-
+    Light render (plot-light.png):
+      Background: warm off-white, matches #FAF8F1 — not pure white, not dark.
+      Chrome: Title "residual-plot · javascript · chartjs · anyplot.ai" in dark ink, comfortably sized, not overflowing. Legend row below title (Zero reference / Residuals / Smoothed trend / Outliers (>2σ)) in dark text. Axis titles "Fitted Value ($1,000s)" and "Residual ($1,000s)" in dark ink with units. Tick labels in a softer dark grey. Grid lines light grey, subtle but visible. All fully readable.
+      Data: ~220 green (#009E73) circular residual points at ~0.7 alpha spread over Fitted Value ($150k-$600k) vs Residual (-80 to +80), a solid black zero-reference line, two amber dashed ±2σ lines with a faint shaded band between them, a light-purple dotted rolling-mean smoothed trend line, and ~11 matte-red triangular outlier points beyond the bands. First series correctly uses brand green.
+      Legibility verdict: PASS.
+
+    Dark render (plot-dark.png):
+      Background: warm near-black, matches #1A1A17 — not pure black, not light.
+      Chrome: Same title and legend, now rendered in light/white ink, fully readable against the dark surface. Axis titles and tick labels in light tones, no dark-on-dark issues anywhere. Zero-reference line correctly flips to a light/white stroke (theme-adaptive ink token). Grid lines subtle dark-grey, still visible.
+      Data: Green circles, amber dashed bands, purple dotted trend line, and matte-red outlier triangles are pixel-identical in color and position to the light render — confirms only chrome flipped, not data colors.
+      Legibility verdict: PASS.
+  criteria_checklist:
+    visual_quality:
+      score: 29
+      max: 30
+      items:
+      - id: VQ-01
+        name: Text Legibility
+        score: 8
+        max: 8
+        passed: true
+        comment: All text readable at appropriate sizes in both themes, no dark-on-dark
+          or light-on-light failures
+      - id: VQ-02
+        name: No Overlap
+        score: 5
+        max: 6
+        passed: true
+        comment: Alpha transparency now softens clusters, but a few points near fitted≈250
+          and fitted≈560 still touch slightly
+      - id: VQ-03
+        name: Element Visibility
+        score: 6
+        max: 6
+        passed: true
+        comment: Alpha=0.7 and appropriate marker size added for n=220, addressing
+          the attempt-1 finding
+      - id: VQ-04
+        name: Color Accessibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Outliers use both matte-red color and triangle shape — CVD-safe redundant
+          encoding
+      - id: VQ-05
+        name: Layout & Canvas
+        score: 4
+        max: 4
+        passed: true
+        comment: Clean proportions, nothing clipped, canvas-gate not triggered
+      - id: VQ-06
+        name: Axis Labels & Title
+        score: 2
+        max: 2
+        passed: true
+        comment: Descriptive axis titles with units
+      - id: VQ-07
+        name: Palette Compliance
+        score: 2
+        max: 2
+        passed: true
+        comment: Brand green first series, semantic red for outliers, amber anchor
+          for threshold, correct theme backgrounds, identical data colors across themes
+    design_excellence:
+      score: 16
+      max: 20
+      items:
+      - id: DE-01
+        name: Aesthetic Sophistication
+        score: 7
+        max: 8
+        passed: true
+        comment: Theme-adaptive band shading, semantic color use, relative-fill technique,
+          and new trend line show real design thought
+      - id: DE-02
+        name: Visual Refinement
+        score: 4
+        max: 6
+        passed: true
+        comment: Subtle grid, L-shaped axis borders, alpha blending; solid but not
+          standout
+      - id: DE-03
+        name: Data Storytelling
+        score: 5
+        max: 6
+        passed: true
+        comment: Outlier highlighting, shaded threshold band, and new smoothed trend
+          line create a clear diagnostic focal hierarchy
+    spec_compliance:
+      score: 15
+      max: 15
+      items:
+      - id: SC-01
+        name: Plot Type
+        score: 5
+        max: 5
+        passed: true
+        comment: Correct residual scatter plot
+      - id: SC-02
+        name: Required Features
+        score: 4
+        max: 4
+        passed: true
+        comment: Zero-reference line, ±2σ bands, outlier color-coding, alpha, and
+          smoothing trend all present
+      - id: SC-03
+        name: Data Mapping
+        score: 3
+        max: 3
+        passed: true
+        comment: X = fitted value, Y = residual (y_true - y_pred), full range shown
+      - id: SC-04
+        name: Title & Legend
+        score: 3
+        max: 3
+        passed: true
+        comment: Title matches mandated format; legend labels are clear and correctly
+          deduplicated
+    data_quality:
+      score: 15
+      max: 15
+      items:
+      - id: DQ-01
+        name: Feature Coverage
+        score: 6
+        max: 6
+        passed: true
+        comment: Now covers all spec-listed features including the two previously-missing
+          optional ones (alpha, smoothing trend)
+      - id: DQ-02
+        name: Realistic Context
+        score: 5
+        max: 5
+        passed: true
+        comment: Plausible house-price regression scenario with realistic heteroscedastic
+          noise
+      - id: DQ-03
+        name: Appropriate Scale
+        score: 4
+        max: 4
+        passed: true
+        comment: Sensible value ranges for the domain
+    code_quality:
+      score: 10
+      max: 10
+      items:
+      - id: CQ-01
+        name: KISS Structure
+        score: 3
+        max: 3
+        passed: true
+        comment: Flat script; small RNG/rgba helpers are appropriate, not over-abstracted
+      - id: CQ-02
+        name: Reproducibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Fixed-seed LCG, fully deterministic
+      - id: CQ-03
+        name: Clean Imports
+        score: 2
+        max: 2
+        passed: true
+        comment: No stray imports, Chart global used directly
+      - id: CQ-04
+        name: Code Elegance
+        score: 2
+        max: 2
+        passed: true
+        comment: Appropriate complexity, no fake UI/interactivity
+      - id: CQ-05
+        name: Output & API
+        score: 1
+        max: 1
+        passed: true
+        comment: 'Correct mount-node contract, animation: false, current scatter/fill
+          API'
+    library_mastery:
+      score: 9
+      max: 10
+      items:
+      - id: LM-01
+        name: Idiomatic Usage
+        score: 4
+        max: 5
+        passed: true
+        comment: Good use of mixed scatter+line datasets and Chart.js recommended
+          patterns
+      - id: LM-02
+        name: Distinctive Features
+        score: 5
+        max: 5
+        passed: true
+        comment: 'Relative fill: ''+2'' index trick, theme-adaptive band tint, legend
+          filter callback, and rolling-window trend computation go well beyond generic
+          usage'
+  verdict: APPROVED
+impl_tags:
+  dependencies: []
+  techniques:
+  - layer-composition
+  - custom-legend
+  patterns:
+  - data-generation
+  dataprep:
+  - rolling-window
+  styling:
+  - alpha-blending
+  - edge-highlighting