From 09339b0b258113a0b887b894283d34f3b061294a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 3 Jun 2026 03:35:36 +0000
Subject: [PATCH 1/5] feat(plotnine): implement piano-roll-midi
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Regen from quality 91. Addressed:
- canvas: fixed figure_size=(8,4.5) dpi=400 → 3200×1800 (was 16×9 dpi=300)
- output: renamed plot.png → plot-{THEME}.png (theme-suffixed)
- theme: full ANYPLOT_THEME env handling with theme-adaptive chrome tokens
- colormap: replaced forbidden scale_fill_cmap(inferno) with imprint_seq
  (scale_fill_gradient low=#009E73 high=#4467A3 per Imprint palette rules)
- background: theme-adaptive PAGE_BG/ELEVATED_BG (was hardcoded white)
- piano key shading: theme-adaptive WHITE_KEY_BG/BLACK_KEY_BG
- title: added language token + fixed domain (python · plotnine · anyplot.ai)
- y-axis crowding: show only C and G notes (octave + dominant)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../implementations/python/plotnine.py        | 152 ++++++++++--------
 1 file changed, 81 insertions(+), 71 deletions(-)

diff --git a/plots/piano-roll-midi/implementations/python/plotnine.py b/plots/piano-roll-midi/implementations/python/plotnine.py
index fd31e00202..65a3e6cc8e 100644
--- a/plots/piano-roll-midi/implementations/python/plotnine.py
+++ b/plots/piano-roll-midi/implementations/python/plotnine.py
@@ -1,9 +1,11 @@
-""" pyplots.ai
+"""anyplot.ai
 piano-roll-midi: MIDI Piano Roll Visualization
-Library: plotnine 0.15.3 | Python 3.14.3
-Quality: 91/100 | Created: 2026-03-07
+Library: plotnine | Python 3.13
+Quality: pending | Created: 2026-06-03
 """
 
+import os
+
 import numpy as np
 import pandas as pd
 from plotnine import (
@@ -20,7 +22,7 @@
     ggplot,
     guide_colorbar,
     labs,
-    scale_fill_cmap,
+    scale_fill_gradient,
     scale_x_continuous,
     scale_y_continuous,
     theme,
@@ -28,11 +30,26 @@
 )
 
 
-# Data - A short chord progression with melody (C major -> F major -> G major -> C major)
+# Theme tokens (Imprint palette, theme-adaptive chrome)
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+
+# Piano key shading (theme-adaptive)
+WHITE_KEY_BG = "#EDE9DE" if THEME == "light" else "#212120"
+BLACK_KEY_BG = "#D8D4C8" if THEME == "light" else "#141413"
+BEAT_LINE = "#C4C0B4" if THEME == "light" else "#2C2C29"
+MEASURE_LINE = "#8A8780" if THEME == "light" else "#4A4A46"
+OCTAVE_LINE = "#ABA89C" if THEME == "light" else "#363632"
+
+# Data — C major → F major → G major → C major chord progression with melody
 np.random.seed(42)
 
 notes = [
-    # Measure 1: C major chord + melody (opening — mf)
+    # Measure 1: C major chord + melody (mf)
     (0.0, 2.0, 48, 80),  # C3 bass
     (0.0, 2.0, 52, 70),  # E3
     (0.0, 2.0, 55, 70),  # G3
@@ -42,17 +59,17 @@
     (2.0, 1.0, 65, 105),  # F4
     (3.0, 0.5, 64, 85),  # E4
     (3.5, 0.5, 62, 80),  # D4
-    # Measure 2: F major chord + melody (building — f to ff)
+    # Measure 2: F major chord + melody (f to ff)
     (4.0, 2.0, 53, 75),  # F3 bass
     (4.0, 2.0, 57, 65),  # A3
     (4.0, 2.0, 60, 65),  # C4
     (4.0, 1.0, 65, 110),  # F4 melody
     (5.0, 0.5, 67, 95),  # G4
     (5.5, 0.5, 69, 100),  # A4
-    (6.0, 1.5, 72, 115),  # C5 high point - CLIMAX
+    (6.0, 1.5, 72, 115),  # C5 — CLIMAX
     (7.5, 0.5, 69, 80),  # A4
     # Measure 3: G major chord + descending melody (diminuendo)
-    (8.0, 2.0, 50, 85),  # D3 bass (G/D inversion — tighter pitch range)
+    (8.0, 2.0, 50, 85),  # D3 bass (G/D inversion)
     (8.0, 2.0, 55, 70),  # G3
     (8.0, 2.0, 59, 70),  # B3
     (8.0, 1.0, 71, 105),  # B4 melody
@@ -61,13 +78,13 @@
     (10.0, 1.0, 65, 95),  # F4
     (11.0, 0.5, 64, 80),  # E4
     (11.5, 0.5, 62, 75),  # D4
-    # Measure 4: C major resolution (ending — p, fading)
+    # Measure 4: C major resolution (p, fading)
     (12.0, 2.0, 48, 90),  # C3 bass
     (12.0, 2.0, 52, 75),  # E3
     (12.0, 2.0, 55, 75),  # G3
-    (12.0, 3.0, 60, 110),  # C4 melody - long resolution
+    (12.0, 3.0, 60, 110),  # C4 — long resolution
     (14.0, 1.0, 64, 70),  # E4
-    (15.0, 1.0, 60, 60),  # C4 ending - soft fade
+    (15.0, 1.0, 60, 60),  # C4 — soft fade
 ]
 
 df = pd.DataFrame(notes, columns=["start", "duration", "pitch", "velocity"])
@@ -75,56 +92,48 @@
 df["ymin"] = df["pitch"] - 0.4
 df["ymax"] = df["pitch"] + 0.4
 
-# MIDI note name mapping
 note_names = ["C", "C♯", "D", "D♯", "E", "F", "F♯", "G", "G♯", "A", "A♯", "B"]
 
-pitch_min = df["pitch"].min() - 1
-pitch_max = df["pitch"].max() + 1
+pitch_min = int(df["pitch"].min()) - 1  # 47
+pitch_max = int(df["pitch"].max()) + 1  # 73
 
-# Background rows for black/white key distinction
+# Background rows — theme-adaptive black/white key shading
 black_key_semitones = {1, 3, 6, 8, 10}
-bg_rows = []
-for p in range(pitch_min, pitch_max + 1):
-    semitone = p % 12
-    is_black = semitone in black_key_semitones
-    bg_rows.append({"ymin": p - 0.5, "ymax": p + 0.5, "fill_color": "#e6e4ef" if is_black else "#f8f7fc"})
-
+bg_rows = [
+    {"ymin": p - 0.5, "ymax": p + 0.5, "fill_color": BLACK_KEY_BG if p % 12 in black_key_semitones else WHITE_KEY_BG}
+    for p in range(pitch_min, pitch_max + 1)
+]
 bg_df = pd.DataFrame(bg_rows)
 
-# Y-axis labels: show only white-key pitches and pitches with notes to reduce crowding
-used_pitches = set(df["pitch"].unique())
-pitch_labels_map = {p: f"{note_names[p % 12]}{p // 12 - 1}" for p in range(pitch_min, pitch_max + 1)}
-# Show white keys that have data, plus octave C notes for orientation
-white_key_semitones = {0, 2, 4, 5, 7, 9, 11}
-label_pitches = sorted(
-    {p for p in used_pitches if p % 12 in white_key_semitones}
-    | {p for p in range(pitch_min, pitch_max + 1) if p % 12 == 0}
-)
-label_names = [pitch_labels_map[p] for p in label_pitches]
+# Y-axis: C (octave markers) and G (dominant) only — avoids adjacent-label crowding
+label_pitches = sorted(p for p in range(pitch_min, pitch_max + 1) if p % 12 in {0, 7})
+label_names = [f"{note_names[p % 12]}{p // 12 - 1}" for p in label_pitches]
 
 # Measure structure
 total_beats = 16
 measure_lines = [0, 4, 8, 12, 16]
 beat_lines = [b for b in range(total_beats + 1) if b not in measure_lines]
 
-# Measure labels at top with chord names
+# Chord labels at measure tops
 measure_labels = pd.DataFrame(
     {"x": [2, 6, 10, 14], "label": ["I  (C)", "IV  (F)", "V  (G)", "I  (C)"], "y": [pitch_max + 0.8] * 4}
 )
 
-# Dynamic markings to enhance storytelling
+# Dynamic markings below piano roll
 dynamic_labels = pd.DataFrame({"x": [2, 6.5, 10, 14.5], "label": ["mf", "ff", "dim.", "p"], "y": [pitch_min - 0.3] * 4})
 
-# Horizontal separators at octave boundaries (every C note)
+# Octave boundary lines at each C note
 octave_cs = [p for p in range(pitch_min, pitch_max + 1) if p % 12 == 0]
 octave_lines = pd.DataFrame(
     {"y": [c - 0.5 for c in octave_cs], "xstart": [-0.3] * len(octave_cs), "xend": [total_beats + 0.3] * len(octave_cs)}
 )
 
-# Plot using theme_void as base for maximum control (plotnine-distinctive)
+title = "piano-roll-midi · python · plotnine · anyplot.ai"
+
+# Plot
 plot = (
     ggplot()
-    # Background rows - alternating shading for black/white keys
+    # Background rows — black/white key distinction
     + geom_rect(
         bg_df,
         aes(xmin=-0.3, xmax=total_beats + 0.3, ymin="ymin", ymax="ymax"),
@@ -132,50 +141,51 @@
         color=None,
         show_legend=False,
     )
-    # Beat grid lines (subtle)
-    + geom_vline(xintercept=beat_lines, color="#d4d2e0", size=0.25, linetype="dotted")
-    # Measure grid lines (stronger)
-    + geom_vline(xintercept=measure_lines, color="#9895b0", size=0.5, linetype="solid")
-    # Octave boundary lines
+    # Beat grid (subtle dotted)
+    + geom_vline(xintercept=beat_lines, color=BEAT_LINE, size=0.25, linetype="dotted")
+    # Measure boundaries (solid)
+    + geom_vline(xintercept=measure_lines, color=MEASURE_LINE, size=0.5, linetype="solid")
+    # Octave boundary lines (dashed)
     + geom_segment(
-        octave_lines, aes(x="xstart", xend="xend", y="y", yend="y"), color="#b0adc5", size=0.35, linetype="dashed"
+        octave_lines, aes(x="xstart", xend="xend", y="y", yend="y"), color=OCTAVE_LINE, size=0.35, linetype="dashed"
+    )
+    # Note rectangles — Imprint sequential colormap (green=soft → blue=loud)
+    + geom_rect(df, aes(xmin="start", xmax="end", ymin="ymin", ymax="ymax", fill="velocity"), color=INK, size=0.3)
+    # Climax annotation
+    + annotate("text", x=7.6, y=72 + 1.0, label="← climax", size=3.0, color="#AE3030", fontstyle="italic", ha="left")
+    # Chord labels at top of each measure
+    + geom_text(measure_labels, aes(x="x", y="y", label="label"), size=3.5, color=INK_SOFT, fontstyle="italic")
+    # Dynamic markings below
+    + geom_text(dynamic_labels, aes(x="x", y="y", label="label"), size=3.0, color=INK_MUTED, fontstyle="italic")
+    # Imprint sequential cmap: #009E73 (soft/piano) → #4467A3 (loud/forte)
+    + scale_fill_gradient(
+        low="#009E73", high="#4467A3", limits=(55, 120), name="Velocity", guide=guide_colorbar(nbin=200)
     )
-    # Note rectangles with velocity color mapping
-    + geom_rect(df, aes(xmin="start", xmax="end", ymin="ymin", ymax="ymax", fill="velocity"), color="#2d2a3e", size=0.3)
-    # Climax annotation using plotnine annotate
-    + annotate("text", x=7.6, y=72 + 1.0, label="← climax", size=9, color="#e05634", fontstyle="italic", ha="left")
-    # Measure chord labels at top
-    + geom_text(measure_labels, aes(x="x", y="y", label="label"), size=11, color="#4a4568", fontstyle="italic")
-    # Dynamic markings below the piano roll
-    + geom_text(dynamic_labels, aes(x="x", y="y", label="label"), size=9, color="#7a7590", fontstyle="italic")
-    # Color scale: viridis for perceptual uniformity and colorblind safety
-    + scale_fill_cmap(cmap_name="inferno", limits=(55, 120), name="Velocity", guide=guide_colorbar(nbin=200))
     + scale_y_continuous(breaks=label_pitches, labels=label_names, expand=(0.02, 0.02))
     + scale_x_continuous(breaks=measure_lines, labels=["0", "4", "8", "12", "16"], expand=(0.01, 0.01))
     + coord_cartesian(xlim=(-0.3, total_beats + 0.3), ylim=(pitch_min - 1.2, pitch_max + 1.5))
-    + labs(x="Time (beats)", y="Pitch (note)", title="piano-roll-midi · plotnine · pyplots.ai")
-    # Start from theme_void for full control, then add back what we need
+    + labs(x="Time (beats)", y="Pitch", title=title)
     + theme_void()
     + theme(
-        figure_size=(16, 9),
-        plot_title=element_text(size=24, weight="bold", color="#2d2a3e", margin={"b": 15}),
-        axis_title_x=element_text(size=20, color="#4a4568", margin={"t": 10}),
-        axis_title_y=element_text(size=20, color="#4a4568", margin={"r": 10}),
-        axis_text_x=element_text(size=16, color="#4a4568"),
-        axis_text_y=element_text(size=16, color="#4a4568"),
-        axis_ticks_major=element_line(color="#9895b0", size=0.5),
-        axis_ticks_length=4,
+        figure_size=(8, 4.5),
+        plot_title=element_text(size=12, weight="bold", color=INK, margin={"b": 8}),
+        axis_title_x=element_text(size=10, color=INK, margin={"t": 6}),
+        axis_title_y=element_text(size=10, color=INK, margin={"r": 6}),
+        axis_text_x=element_text(size=8, color=INK_SOFT),
+        axis_text_y=element_text(size=8, color=INK_SOFT),
+        axis_ticks_major=element_line(color=INK_SOFT, size=0.4),
+        axis_ticks_length=3,
         legend_position="right",
-        legend_title=element_text(size=16, color="#4a4568"),
-        legend_text=element_text(size=14, color="#4a4568"),
-        legend_background=element_rect(fill="#f8f7fc", color=None),
-        legend_key_height=40,
-        legend_key_width=12,
-        panel_background=element_rect(fill="#f8f7fc", color=None),
-        plot_background=element_rect(fill="white", color=None),
+        legend_title=element_text(size=8, color=INK),
+        legend_text=element_text(size=8, color=INK_SOFT),
+        legend_background=element_rect(fill=ELEVATED_BG, color=None),
+        legend_key_height=30,
+        legend_key_width=10,
+        panel_background=element_rect(fill=PAGE_BG, color=None),
+        plot_background=element_rect(fill=PAGE_BG, color=None),
         plot_margin=0.02,
     )
 )
 
 # Save
-plot.save("plot.png", dpi=300, verbose=False)
+plot.save(f"plot-{THEME}.png", dpi=400, width=8, height=4.5, units="in", verbose=False)

From 0794d608ac28281e7a41582cca9188282d123e1c Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 3 Jun 2026 03:35:49 +0000
Subject: [PATCH 2/5] chore(plotnine): add metadata for piano-roll-midi

---
 .../metadata/python/plotnine.yaml             | 231 ++----------------
 1 file changed, 16 insertions(+), 215 deletions(-)

diff --git a/plots/piano-roll-midi/metadata/python/plotnine.yaml b/plots/piano-roll-midi/metadata/python/plotnine.yaml
index dcfce384ba..2dfc01f92e 100644
--- a/plots/piano-roll-midi/metadata/python/plotnine.yaml
+++ b/plots/piano-roll-midi/metadata/python/plotnine.yaml
@@ -1,220 +1,21 @@
+# Per-library metadata for plotnine implementation of piano-roll-midi
+# Auto-generated by impl-generate.yml
+
 library: plotnine
+language: python
 specification_id: piano-roll-midi
 created: '2026-03-07T19:46:37Z'
-updated: '2026-03-07T20:15:24Z'
-generated_by: claude-opus-4-5-20251101
-workflow_run: 22805912195
+updated: '2026-06-03T03:35:48Z'
+generated_by: claude-sonnet
+workflow_run: 26861817386
 issue: 4565
-python_version: 3.14.3
-library_version: 0.15.3
-preview_url: https://storage.googleapis.com/anyplot-images/plots/piano-roll-midi/plotnine/plot.png
-preview_html: null
-quality_score: 91
+language_version: 3.13.13
+library_version: 0.15.5
+preview_url_light: https://storage.googleapis.com/anyplot-images/plots/piano-roll-midi/python/plotnine/plot-light.png
+preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/piano-roll-midi/python/plotnine/plot-dark.png
+preview_html_light: null
+preview_html_dark: null
+quality_score: null
 review:
-  strengths:
-  - Excellent data storytelling with chord labels, dynamic markings, and climax annotation
-    creating a musical narrative
-  - Cohesive purple-themed design with inferno colormap that feels domain-appropriate
-  - Complete spec compliance with all required features present
-  - Realistic musical data with proper I-IV-V-I progression showing varied durations
-    and dynamics
-  - Clean use of theme_void() as a base for full visual control
-  weaknesses:
-  - Y-axis pitch labels slightly crowded where adjacent pitches are both labeled
-  image_description: The plot displays a MIDI piano roll visualization on a light
-    purple/white background. Horizontal colored rectangles represent musical notes,
-    positioned by pitch (y-axis, labeled C3 through C5 with note names) and time (x-axis,
-    0-16 beats). The inferno colormap maps velocity from dark purple (soft, ~60) to
-    yellow (loud, ~120). Alternating row shading distinguishes black keys (slightly
-    darker lavender) from white keys (lighter). Vertical dotted lines mark beats,
-    solid gray lines mark measure boundaries at beats 0, 4, 8, 12, 16. Chord labels
-    (I (C), IV (F), V (G), I (C)) appear at the top, and dynamic markings (mf, ff,
-    dim., p) at the bottom. A red italic "← climax" annotation marks the C5 note.
-    The title reads "piano-roll-midi · plotnine · pyplots.ai" in bold dark text. A
-    velocity colorbar legend is on the right side.
-  criteria_checklist:
-    visual_quality:
-      score: 28
-      max: 30
-      items:
-      - id: VQ-01
-        name: Text Legibility
-        score: 8
-        max: 8
-        passed: true
-        comment: 'All font sizes explicitly set: title=24, axis titles=20, ticks=16,
-          legend=16/14'
-      - id: VQ-02
-        name: No Overlap
-        score: 5
-        max: 6
-        passed: true
-        comment: Slight crowding on y-axis where adjacent pitches have labels close
-          together
-      - id: VQ-03
-        name: Element Visibility
-        score: 6
-        max: 6
-        passed: true
-        comment: Note rectangles clearly visible with good height and contrast
-      - id: VQ-04
-        name: Color Accessibility
-        score: 4
-        max: 4
-        passed: true
-        comment: Inferno colormap is perceptually uniform and colorblind-safe
-      - id: VQ-05
-        name: Layout & Canvas
-        score: 3
-        max: 4
-        passed: true
-        comment: Good 16:9 proportions, minor extra whitespace above chord labels
-      - id: VQ-06
-        name: Axis Labels & Title
-        score: 2
-        max: 2
-        passed: true
-        comment: Time (beats) and Pitch (note) are descriptive with units
-    design_excellence:
-      score: 16
-      max: 20
-      items:
-      - id: DE-01
-        name: Aesthetic Sophistication
-        score: 6
-        max: 8
-        passed: true
-        comment: Cohesive purple color scheme with inferno colormap, chord numerals
-          and dynamic markings
-      - id: DE-02
-        name: Visual Refinement
-        score: 5
-        max: 6
-        passed: true
-        comment: theme_void base with selective restoration, subtle grid hierarchy,
-          polished legend
-      - id: DE-03
-        name: Data Storytelling
-        score: 5
-        max: 6
-        passed: true
-        comment: Musical narrative with climax annotation, dynamic markings, chord
-          progression labels
-    spec_compliance:
-      score: 15
-      max: 15
-      items:
-      - id: SC-01
-        name: Plot Type
-        score: 5
-        max: 5
-        passed: true
-        comment: Correct piano roll with horizontal rectangles by pitch and time
-      - id: SC-02
-        name: Required Features
-        score: 4
-        max: 4
-        passed: true
-        comment: 'All spec features: key shading, note names, grid lines, velocity
-          coloring, auto-fit range'
-      - id: SC-03
-        name: Data Mapping
-        score: 3
-        max: 3
-        passed: true
-        comment: X=time (beats), Y=pitch (note names), all data visible
-      - id: SC-04
-        name: Title & Legend
-        score: 3
-        max: 3
-        passed: true
-        comment: Correct title format, velocity colorbar legend present
-    data_quality:
-      score: 15
-      max: 15
-      items:
-      - id: DQ-01
-        name: Feature Coverage
-        score: 6
-        max: 6
-        passed: true
-        comment: Chord progressions, varying durations, varying velocities, bass+melody
-          separation
-      - id: DQ-02
-        name: Realistic Context
-        score: 5
-        max: 5
-        passed: true
-        comment: Real I-IV-V-I chord progression in C major with melodic contour
-      - id: DQ-03
-        name: Appropriate Scale
-        score: 4
-        max: 4
-        passed: true
-        comment: MIDI pitches 48-72, velocities 60-115, durations 0.5-3.0 beats
-    code_quality:
-      score: 10
-      max: 10
-      items:
-      - id: CQ-01
-        name: KISS Structure
-        score: 3
-        max: 3
-        passed: true
-        comment: 'Linear flow: imports, data, dataframes, plot, save'
-      - id: CQ-02
-        name: Reproducibility
-        score: 2
-        max: 2
-        passed: true
-        comment: np.random.seed(42) set, data is deterministic
-      - id: CQ-03
-        name: Clean Imports
-        score: 2
-        max: 2
-        passed: true
-        comment: All imports are used
-      - id: CQ-04
-        name: Code Elegance
-        score: 2
-        max: 2
-        passed: true
-        comment: Clean, well-organized, appropriate complexity
-      - id: CQ-05
-        name: Output & API
-        score: 1
-        max: 1
-        passed: true
-        comment: Saves as plot.png with dpi=300, current API
-    library_mastery:
-      score: 7
-      max: 10
-      items:
-      - id: LM-01
-        name: Idiomatic Usage
-        score: 4
-        max: 5
-        passed: true
-        comment: Proper grammar of graphics with theme_void base for full control
-      - id: LM-02
-        name: Distinctive Features
-        score: 3
-        max: 5
-        passed: true
-        comment: theme_void, scale_fill_cmap with guide_colorbar, annotate, per-layer
-          data
-  verdict: APPROVED
-impl_tags:
-  dependencies: []
-  techniques:
-  - annotations
-  - layer-composition
-  - colorbar
-  patterns:
-  - data-generation
-  dataprep: []
-  styling:
-  - minimal-chrome
-  - custom-colormap
-  - grid-styling
-  - edge-highlighting
+  strengths: []
+  weaknesses: []

From 2f34ba86c44efdc25e12058b5581746fec167c80 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 3 Jun 2026 03:42:52 +0000
Subject: [PATCH 3/5] chore(plotnine): update quality score 88 and review
 feedback for piano-roll-midi

---
 .../implementations/python/plotnine.py        |   6 +-
 .../metadata/python/plotnine.yaml             | 261 +++++++++++++++++-
 2 files changed, 257 insertions(+), 10 deletions(-)

diff --git a/plots/piano-roll-midi/implementations/python/plotnine.py b/plots/piano-roll-midi/implementations/python/plotnine.py
index 65a3e6cc8e..55e77ca4b3 100644
--- a/plots/piano-roll-midi/implementations/python/plotnine.py
+++ b/plots/piano-roll-midi/implementations/python/plotnine.py
@@ -1,7 +1,7 @@
-"""anyplot.ai
+""" anyplot.ai
 piano-roll-midi: MIDI Piano Roll Visualization
-Library: plotnine | Python 3.13
-Quality: pending | Created: 2026-06-03
+Library: plotnine 0.15.5 | Python 3.13.13
+Quality: 88/100 | Updated: 2026-06-03
 """
 
 import os
diff --git a/plots/piano-roll-midi/metadata/python/plotnine.yaml b/plots/piano-roll-midi/metadata/python/plotnine.yaml
index 2dfc01f92e..561bcf5a7d 100644
--- a/plots/piano-roll-midi/metadata/python/plotnine.yaml
+++ b/plots/piano-roll-midi/metadata/python/plotnine.yaml
@@ -1,11 +1,8 @@
-# Per-library metadata for plotnine implementation of piano-roll-midi
-# Auto-generated by impl-generate.yml
-
 library: plotnine
 language: python
 specification_id: piano-roll-midi
 created: '2026-03-07T19:46:37Z'
-updated: '2026-06-03T03:35:48Z'
+updated: '2026-06-03T03:42:52Z'
 generated_by: claude-sonnet
 workflow_run: 26861817386
 issue: 4565
@@ -15,7 +12,257 @@ preview_url_light: https://storage.googleapis.com/anyplot-images/plots/piano-rol
 preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/piano-roll-midi/python/plotnine/plot-dark.png
 preview_html_light: null
 preview_html_dark: null
-quality_score: null
+quality_score: 88
 review:
-  strengths: []
-  weaknesses: []
+  strengths:
+  - 'Full spec compliance: all four required piano-roll features implemented (note
+    rects, key-row shading, beat/measure grid, velocity colormap)'
+  - 'Excellent data storytelling: chord labels, dynamic markings, and climax annotation
+    working as cohesive musical narrative'
+  - 'Correct Imprint sequential colormap (#009E73 -> #4467A3) with musically appropriate
+    direction (soft=green, loud=blue)'
+  - Strong use of plotnine layer composition — multiple independent dataframes passed
+    to individual geoms idiomatically
+  - 'Perfect code quality: clean flat script, deterministic seed, correct output naming
+    convention'
+  weaknesses:
+  - 'Dark-mode piano key row distinction is nearly invisible — WHITE_KEY_BG=#212120
+    and BLACK_KEY_BG=#141413 are too similar over #1A1A17 background; increase the
+    contrast (e.g. #272720 vs #0D0D0B) so the black/white key metaphor reads in both
+    themes'
+  - 'Top margin is crowded: chord labels (y=pitch_max+0.8) and climax annotation (y=72+1.0)
+    are only 0.8 pitch units apart — extend ylim top to pitch_max+2.5 and move chord
+    labels to y=pitch_max+1.8 for clear separation'
+  - Dynamic markings at y=pitch_min-0.3 are wedged between the piano roll and x-axis
+    ticks; move to y=pitch_min-0.6 and expand coord_cartesian y-bottom accordingly
+  - Chord labels (size=3.5mm) and dynamic markings (size=3.0mm) may fall below mobile-readable
+    threshold at ~400px scaled width — increase to 3.5/4.0mm respectively
+  image_description: |-
+    Light render (plot-light.png):
+      Background: Warm off-white #FAF8F1 — correct theme surface
+      Chrome: Title "piano-roll-midi · python · plotnine · anyplot.ai" bold, ~65% of plot width, clearly readable in dark INK. Axis labels "Pitch" (y) and "Time (beats)" (x) at 10pt in INK, clearly readable. Tick labels C3/G3/C4/G4/C5 and 0/4/8/12/16 at 8pt INK_SOFT, readable. Chord labels (I (C), IV (F), V (G), I (C)) in italic INK_SOFT at top margin — small but readable at full resolution. Dynamic markings (mf, ff, dim., p) in italic INK_MUTED at bottom margin — small but readable.
+      Data: Alternating white-key (#EDE9DE) and black-key (#D8D4C8) horizontal bands clearly distinguish piano keyboard rows. Note rectangles colored via Imprint imprint_seq (#009E73 green for low velocity -> #4467A3 blue for high velocity) with dark INK borders. Dotted beat lines and solid measure lines provide time structure. Dashed octave boundary lines at C notes. "← climax" annotation in #AE3030 matte red marks peak note at C5. Colorbar "Velocity" legend 60-120 on right side.
+      Legibility verdict: PASS
+
+    Dark render (plot-dark.png):
+      Background: Warm near-black #1A1A17 — correct theme surface
+      Chrome: All chrome tokens correctly flipped to light values. Title in #F0EFE8 (INK dark-theme), clearly readable against dark background. Axis labels in #F0EFE8, readable. Tick labels in #B8B7B0 (INK_SOFT dark-theme), readable. Chord labels and dynamic markings in lighter tones, readable. No dark-on-dark text failure detected.
+      Data: Data colors (green-to-blue gradient) are identical to light render — Imprint palette positions stay constant across themes as required. Note rectangles clearly visible against dark background. Beat/measure lines visible with adjusted dark-theme colors. HOWEVER: the piano key row alternation (WHITE_KEY_BG=#212120 vs BLACK_KEY_BG=#141413) is barely perceptible over the #1A1A17 background — the black/white key distinction is much weaker than in the light render.
+      Legibility verdict: PASS (with concern: piano-key row distinction extremely faint in dark mode, spec requires visible alternating shading)
+  criteria_checklist:
+    visual_quality:
+      score: 26
+      max: 30
+      items:
+      - id: VQ-01
+        name: Text Legibility
+        score: 7
+        max: 8
+        passed: true
+        comment: Title 12pt, axis labels 10pt, tick labels 8pt all explicit and readable.
+          Chord labels (3.5mm) and dynamic markings (3.0mm) readable at full canvas
+          but may be borderline at mobile scale.
+      - id: VQ-02
+        name: No Overlap
+        score: 5
+        max: 6
+        passed: true
+        comment: No hard overlaps. Climax annotation (x=7.6, y=73) is tight against
+          IV(F) chord label (x=6, y=73.8) creating crowded top margin without actual
+          collision.
+      - id: VQ-03
+        name: Element Visibility
+        score: 5
+        max: 6
+        passed: true
+        comment: 'Note rects well-defined with INK borders. Velocity gradient reads
+          clearly. Piano key row contrast in dark theme is very faint (#212120 vs
+          #141413 over #1A1A17).'
+      - id: VQ-04
+        name: Color Accessibility
+        score: 2
+        max: 2
+        passed: true
+        comment: Imprint sequential cmap (#009E73->#4467A3) is CVD-safe. No red-green
+          as sole signal.
+      - id: VQ-05
+        name: Layout & Canvas
+        score: 3
+        max: 4
+        passed: true
+        comment: 3200x1800 correct. Good overall proportions. Minor crowding in top
+          margin (chord labels + climax annotation) and bottom margin (dynamic labels
+          between piano roll and x-ticks).
+      - id: VQ-06
+        name: Axis Labels & Title
+        score: 2
+        max: 2
+        passed: true
+        comment: Title matches required format exactly. X=Time (beats) with units,
+          Y=Pitch with note-name tick labels (C3-C5).
+      - id: VQ-07
+        name: Palette Compliance
+        score: 2
+        max: 2
+        passed: true
+        comment: 'scale_fill_gradient(low=#009E73, high=#4467A3) is exact imprint_seq
+          cmap. Backgrounds #FAF8F1/#1A1A17. All chrome theme-adaptive.'
+    design_excellence:
+      score: 14
+      max: 20
+      items:
+      - id: DE-01
+        name: Aesthetic Sophistication
+        score: 5
+        max: 8
+        passed: true
+        comment: 'Well above generic defaults: custom piano-key background rows, differentiated
+          beat/measure lines, dashed octave boundaries, chord symbols, dynamic markings.
+          Thoughtful DAW-inspired design.'
+      - id: DE-02
+        name: Visual Refinement
+        score: 4
+        max: 6
+        passed: true
+        comment: theme_void() removes superfluous chrome. Background rows replace
+          panel background meaningfully. Beat/measure visual hierarchy is deliberate.
+          Legend uses ELEVATED_BG frame.
+      - id: DE-03
+        name: Data Storytelling
+        score: 5
+        max: 6
+        passed: true
+        comment: Climax annotation guides viewer to musical high point. Chord progression
+          labels (I->IV->V->I) frame harmonic arc. Dynamic markings (mf->ff->dim.->p)
+          narrate intensity curve. Multiple storytelling layers working cohesively.
+    spec_compliance:
+      score: 15
+      max: 15
+      items:
+      - id: SC-01
+        name: Plot Type
+        score: 5
+        max: 5
+        passed: true
+        comment: 'Correct MIDI piano roll: horizontal rectangles by pitch (y) and
+          time onset (x), width=duration.'
+      - id: SC-02
+        name: Required Features
+        score: 4
+        max: 4
+        passed: true
+        comment: Y-axis note names, alternating key shading, beat+measure grid lines,
+          velocity sequential colormap, pitch range auto-fit — all present.
+      - id: SC-03
+        name: Data Mapping
+        score: 3
+        max: 3
+        passed: true
+        comment: X=time beats, Y=MIDI pitch as note names, color=velocity, width=duration.
+          All 4 data dimensions mapped correctly.
+      - id: SC-04
+        name: Title & Legend
+        score: 3
+        max: 3
+        passed: true
+        comment: Title piano-roll-midi · python · plotnine · anyplot.ai exact match.
+          Velocity colorbar with 60/80/100/120 breaks.
+    data_quality:
+      score: 15
+      max: 15
+      items:
+      - id: DQ-01
+        name: Feature Coverage
+        score: 6
+        max: 6
+        passed: true
+        comment: 'All piano-roll dimensions: pitch, onset, duration, velocity. Musical
+          annotation layers demonstrate full use of the format.'
+      - id: DQ-02
+        name: Realistic Context
+        score: 5
+        max: 5
+        passed: true
+        comment: Classic C->F->G->C chord progression with realistic MIDI voice leading,
+          velocity dynamics (mf->ff->dim.->p), melodic climax at C5. Musically plausible
+          and content-neutral.
+      - id: DQ-03
+        name: Appropriate Scale
+        score: 4
+        max: 4
+        passed: true
+        comment: 35 notes over 16 beats (4 measures) within 20-200 note / 4-16 measure
+          spec range. Pitch C3-C5 (MIDI 48-72) is realistic.
+    code_quality:
+      score: 10
+      max: 10
+      items:
+      - id: CQ-01
+        name: KISS Structure
+        score: 3
+        max: 3
+        passed: true
+        comment: Flat script, no unnecessary functions or classes.
+      - id: CQ-02
+        name: Reproducibility
+        score: 2
+        max: 2
+        passed: true
+        comment: np.random.seed(42) set.
+      - id: CQ-03
+        name: Clean Imports
+        score: 2
+        max: 2
+        passed: true
+        comment: All imports used, no dead imports detected.
+      - id: CQ-04
+        name: Code Elegance
+        score: 2
+        max: 2
+        passed: true
+        comment: Clear readable structure, well-named variables, no fake UI elements.
+      - id: CQ-05
+        name: Output & API
+        score: 1
+        max: 1
+        passed: true
+        comment: Saves as plot-{THEME}.png with correct canvas settings (dpi=400,
+          width=8, height=4.5).
+    library_mastery:
+      score: 8
+      max: 10
+      items:
+      - id: LM-01
+        name: Idiomatic Usage
+        score: 4
+        max: 5
+        passed: true
+        comment: Correct grammar-of-graphics layering. Multiple independent dataframes
+          passed to individual geoms idiomatically. coord_cartesian for precise axis
+          control is the right plotnine pattern.
+      - id: LM-02
+        name: Distinctive Features
+        score: 4
+        max: 5
+        passed: true
+        comment: 'Uses plotnine layer composition: geom_rect for both background rows
+          and note rects (two datasets), geom_vline + geom_segment + geom_text + annotate
+          in one pipeline. guide_colorbar(nbin=200) for smooth gradient. scale_y_continuous
+          with fully custom breaks/labels for pitch names.'
+  verdict: APPROVED
+impl_tags:
+  dependencies: []
+  techniques:
+  - colorbar
+  - annotations
+  - layer-composition
+  - manual-ticks
+  patterns:
+  - data-generation
+  - iteration-over-groups
+  dataprep: []
+  styling:
+  - minimal-chrome
+  - custom-colormap
+  - edge-highlighting
+  - grid-styling

From c6bac00f67be8edaba0f58e4570601b6b1712b8c Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 3 Jun 2026 03:47:41 +0000
Subject: [PATCH 4/5] fix(plotnine): address review feedback for
 piano-roll-midi

Attempt 1/3 - fixes based on AI review
---
 .../implementations/python/plotnine.py         | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/plots/piano-roll-midi/implementations/python/plotnine.py b/plots/piano-roll-midi/implementations/python/plotnine.py
index 55e77ca4b3..a8a3196dd2 100644
--- a/plots/piano-roll-midi/implementations/python/plotnine.py
+++ b/plots/piano-roll-midi/implementations/python/plotnine.py
@@ -1,4 +1,4 @@
-""" anyplot.ai
+"""anyplot.ai
 piano-roll-midi: MIDI Piano Roll Visualization
 Library: plotnine 0.15.5 | Python 3.13.13
 Quality: 88/100 | Updated: 2026-06-03
@@ -38,9 +38,9 @@
 INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
 INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
 
-# Piano key shading (theme-adaptive)
-WHITE_KEY_BG = "#EDE9DE" if THEME == "light" else "#212120"
-BLACK_KEY_BG = "#D8D4C8" if THEME == "light" else "#141413"
+# Piano key shading (theme-adaptive) — dark values boosted for visible contrast over #1A1A17
+WHITE_KEY_BG = "#EDE9DE" if THEME == "light" else "#272720"
+BLACK_KEY_BG = "#D8D4C8" if THEME == "light" else "#0D0D0B"
 BEAT_LINE = "#C4C0B4" if THEME == "light" else "#2C2C29"
 MEASURE_LINE = "#8A8780" if THEME == "light" else "#4A4A46"
 OCTAVE_LINE = "#ABA89C" if THEME == "light" else "#363632"
@@ -116,11 +116,11 @@
 
 # Chord labels at measure tops
 measure_labels = pd.DataFrame(
-    {"x": [2, 6, 10, 14], "label": ["I  (C)", "IV  (F)", "V  (G)", "I  (C)"], "y": [pitch_max + 0.8] * 4}
+    {"x": [2, 6, 10, 14], "label": ["I  (C)", "IV  (F)", "V  (G)", "I  (C)"], "y": [pitch_max + 1.8] * 4}
 )
 
 # Dynamic markings below piano roll
-dynamic_labels = pd.DataFrame({"x": [2, 6.5, 10, 14.5], "label": ["mf", "ff", "dim.", "p"], "y": [pitch_min - 0.3] * 4})
+dynamic_labels = pd.DataFrame({"x": [2, 6.5, 10, 14.5], "label": ["mf", "ff", "dim.", "p"], "y": [pitch_min - 0.6] * 4})
 
 # Octave boundary lines at each C note
 octave_cs = [p for p in range(pitch_min, pitch_max + 1) if p % 12 == 0]
@@ -154,16 +154,16 @@
     # Climax annotation
     + annotate("text", x=7.6, y=72 + 1.0, label="← climax", size=3.0, color="#AE3030", fontstyle="italic", ha="left")
     # Chord labels at top of each measure
-    + geom_text(measure_labels, aes(x="x", y="y", label="label"), size=3.5, color=INK_SOFT, fontstyle="italic")
+    + geom_text(measure_labels, aes(x="x", y="y", label="label"), size=4.0, color=INK_SOFT, fontstyle="italic")
     # Dynamic markings below
-    + geom_text(dynamic_labels, aes(x="x", y="y", label="label"), size=3.0, color=INK_MUTED, fontstyle="italic")
+    + geom_text(dynamic_labels, aes(x="x", y="y", label="label"), size=3.5, color=INK_MUTED, fontstyle="italic")
     # Imprint sequential cmap: #009E73 (soft/piano) → #4467A3 (loud/forte)
     + scale_fill_gradient(
         low="#009E73", high="#4467A3", limits=(55, 120), name="Velocity", guide=guide_colorbar(nbin=200)
     )
     + scale_y_continuous(breaks=label_pitches, labels=label_names, expand=(0.02, 0.02))
     + scale_x_continuous(breaks=measure_lines, labels=["0", "4", "8", "12", "16"], expand=(0.01, 0.01))
-    + coord_cartesian(xlim=(-0.3, total_beats + 0.3), ylim=(pitch_min - 1.2, pitch_max + 1.5))
+    + coord_cartesian(xlim=(-0.3, total_beats + 0.3), ylim=(pitch_min - 1.5, pitch_max + 2.5))
     + labs(x="Time (beats)", y="Pitch", title=title)
     + theme_void()
     + theme(

From b45d490cb3f04d3182a0243235e1515e8f72a659 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 3 Jun 2026 03:55:27 +0000
Subject: [PATCH 5/5] chore(plotnine): update quality score 91 and review
 feedback for piano-roll-midi

---
 .../implementations/python/plotnine.py        |   4 +-
 .../metadata/python/plotnine.yaml             | 225 ++++++++++--------
 2 files changed, 132 insertions(+), 97 deletions(-)

diff --git a/plots/piano-roll-midi/implementations/python/plotnine.py b/plots/piano-roll-midi/implementations/python/plotnine.py
index a8a3196dd2..6518397f5d 100644
--- a/plots/piano-roll-midi/implementations/python/plotnine.py
+++ b/plots/piano-roll-midi/implementations/python/plotnine.py
@@ -1,7 +1,7 @@
-"""anyplot.ai
+""" anyplot.ai
 piano-roll-midi: MIDI Piano Roll Visualization
 Library: plotnine 0.15.5 | Python 3.13.13
-Quality: 88/100 | Updated: 2026-06-03
+Quality: 91/100 | Updated: 2026-06-03
 """
 
 import os
diff --git a/plots/piano-roll-midi/metadata/python/plotnine.yaml b/plots/piano-roll-midi/metadata/python/plotnine.yaml
index 561bcf5a7d..07aecf677b 100644
--- a/plots/piano-roll-midi/metadata/python/plotnine.yaml
+++ b/plots/piano-roll-midi/metadata/python/plotnine.yaml
@@ -2,7 +2,7 @@ library: plotnine
 language: python
 specification_id: piano-roll-midi
 created: '2026-03-07T19:46:37Z'
-updated: '2026-06-03T03:42:52Z'
+updated: '2026-06-03T03:55:27Z'
 generated_by: claude-sonnet
 workflow_run: 26861817386
 issue: 4565
@@ -12,46 +12,54 @@ preview_url_light: https://storage.googleapis.com/anyplot-images/plots/piano-rol
 preview_url_dark: https://storage.googleapis.com/anyplot-images/plots/piano-roll-midi/python/plotnine/plot-dark.png
 preview_html_light: null
 preview_html_dark: null
-quality_score: 88
+quality_score: 91
 review:
   strengths:
-  - 'Full spec compliance: all four required piano-roll features implemented (note
-    rects, key-row shading, beat/measure grid, velocity colormap)'
-  - 'Excellent data storytelling: chord labels, dynamic markings, and climax annotation
-    working as cohesive musical narrative'
-  - 'Correct Imprint sequential colormap (#009E73 -> #4467A3) with musically appropriate
-    direction (soft=green, loud=blue)'
-  - Strong use of plotnine layer composition — multiple independent dataframes passed
-    to individual geoms idiomatically
-  - 'Perfect code quality: clean flat script, deterministic seed, correct output naming
-    convention'
+  - Piano-key alternating backgrounds with correct theme adaptation (WHITE_KEY_BG/BLACK_KEY_BG
+    tokens) — genuinely distinctive domain-aware design
+  - Three-tier grid hierarchy (dotted beat lines, solid measure boundaries, dashed
+    octave lines) creates elegant visual structure
+  - Chord progression labels (I, IV, V, I) and dynamic markings (mf, ff, dim., p)
+    provide real musical narrative context
+  - 'Imprint sequential colormap (#009E73 soft → #4467A3 loud) applied correctly for
+    velocity encoding — proper imprint_seq use'
+  - 'Complete spec compliance: note names on Y-axis, velocity colorbar, beat/measure
+    grid, pitch range auto-fitted, all required features present'
+  - Flat KISS code structure with all font sizes explicitly set via element_text —
+    no functions or classes, fully reproducible with hardcoded data
+  - Climax annotation (#AE3030 italic) correctly highlights the musical peak at C5
+    in measure 2
+  - Both themes render correctly with no dark-on-dark or light-on-light failures —
+    all chrome tokens thread through properly
   weaknesses:
-  - 'Dark-mode piano key row distinction is nearly invisible — WHITE_KEY_BG=#212120
-    and BLACK_KEY_BG=#141413 are too similar over #1A1A17 background; increase the
-    contrast (e.g. #272720 vs #0D0D0B) so the black/white key metaphor reads in both
-    themes'
-  - 'Top margin is crowded: chord labels (y=pitch_max+0.8) and climax annotation (y=72+1.0)
-    are only 0.8 pitch units apart — extend ylim top to pitch_max+2.5 and move chord
-    labels to y=pitch_max+1.8 for clear separation'
-  - Dynamic markings at y=pitch_min-0.3 are wedged between the piano roll and x-axis
-    ticks; move to y=pitch_min-0.6 and expand coord_cartesian y-bottom accordingly
-  - Chord labels (size=3.5mm) and dynamic markings (size=3.0mm) may fall below mobile-readable
-    threshold at ~400px scaled width — increase to 3.5/4.0mm respectively
+  - 'In dark render, black-key rows (#0D0D0B) against the #1A1A17 background provide
+    very little contrast — the piano key distinction is barely perceptible in dark
+    mode, making the chromatic structure hard to read. Consider boosting BLACK_KEY_BG
+    dark value slightly (e.g. #151510) while keeping it below #1A1A17.'
+  - 'LM-02: The plotnine implementation uses the grammar of graphics well but a piano
+    roll of this type can be replicated in matplotlib with similar effort — no distinctively
+    plotnine-only feature (e.g. stat_* transforms, facet_grid, position adjustments)
+    is leveraged.'
+  - 'DE-03: The data storytelling through chord labels and dynamic markings is good
+    but the visual hierarchy between the melody notes (higher pitch, high velocity)
+    and accompaniment chords (lower pitch, lower velocity) is implicit rather than
+    visually reinforced — e.g., a subtle size or alpha difference between melody and
+    bass notes would strengthen the focal point.'
   image_description: |-
     Light render (plot-light.png):
-      Background: Warm off-white #FAF8F1 — correct theme surface
-      Chrome: Title "piano-roll-midi · python · plotnine · anyplot.ai" bold, ~65% of plot width, clearly readable in dark INK. Axis labels "Pitch" (y) and "Time (beats)" (x) at 10pt in INK, clearly readable. Tick labels C3/G3/C4/G4/C5 and 0/4/8/12/16 at 8pt INK_SOFT, readable. Chord labels (I (C), IV (F), V (G), I (C)) in italic INK_SOFT at top margin — small but readable at full resolution. Dynamic markings (mf, ff, dim., p) in italic INK_MUTED at bottom margin — small but readable.
-      Data: Alternating white-key (#EDE9DE) and black-key (#D8D4C8) horizontal bands clearly distinguish piano keyboard rows. Note rectangles colored via Imprint imprint_seq (#009E73 green for low velocity -> #4467A3 blue for high velocity) with dark INK borders. Dotted beat lines and solid measure lines provide time structure. Dashed octave boundary lines at C notes. "← climax" annotation in #AE3030 matte red marks peak note at C5. Colorbar "Velocity" legend 60-120 on right side.
-      Legibility verdict: PASS
+      Background: Warm off-white #FAF8F1 — correct. The piano roll rows alternate between two subtle warm grays: lighter (#EDE9DE) for white keys and slightly darker (#D8D4C8) for black keys. The contrast between these two shading values is clearly visible and creates the piano-keyboard-style visual structure.
+      Chrome: Bold title "piano-roll-midi · python · plotnine · anyplot.ai" is readable in dark #1A1A17 ink. Y-axis tick labels (C3, G3, C4, G4, C5) and X-axis tick labels (0, 4, 8, 12, 16) are clearly readable in #4A4A44 (INK_SOFT). X-axis label "Time (beats)" and Y-axis label "Pitch" are readable in #1A1A17. Chord labels (I (C), IV (F), V (G), I (C)) and dynamic markings (mf, ff, dim., p) are visible in muted ink tones. Velocity colorbar labeled "Velocity" with 60/80/100/120 ticks is readable.
+      Data: Note rectangles rendered from #009E73 (green, low velocity ~60) to #4467A3 (blue, high velocity ~115). The C5 "climax" note at beat 6–7.5 is deep blue (velocity 115), clearly the peak. Bass notes (C3, E3, G3) are rendered in mid-green. Melody notes show the crescendo to climax and subsequent diminuendo. "← climax" annotation in #AE3030 italic marks the peak. Measure lines (solid), beat lines (dotted), octave lines (dashed) provide clear structural grid.
+      Legibility verdict: PASS — all text readable, correct theme colors throughout.
 
     Dark render (plot-dark.png):
-      Background: Warm near-black #1A1A17 — correct theme surface
-      Chrome: All chrome tokens correctly flipped to light values. Title in #F0EFE8 (INK dark-theme), clearly readable against dark background. Axis labels in #F0EFE8, readable. Tick labels in #B8B7B0 (INK_SOFT dark-theme), readable. Chord labels and dynamic markings in lighter tones, readable. No dark-on-dark text failure detected.
-      Data: Data colors (green-to-blue gradient) are identical to light render — Imprint palette positions stay constant across themes as required. Note rectangles clearly visible against dark background. Beat/measure lines visible with adjusted dark-theme colors. HOWEVER: the piano key row alternation (WHITE_KEY_BG=#212120 vs BLACK_KEY_BG=#141413) is barely perceptible over the #1A1A17 background — the black/white key distinction is much weaker than in the light render.
-      Legibility verdict: PASS (with concern: piano-key row distinction extremely faint in dark mode, spec requires visible alternating shading)
+      Background: Warm near-black #1A1A17 — correct. Row alternation is present: white-key rows (#272720) are subtly lighter than the background, black-key rows (#0D0D0B) are darker — nearly invisible at #0D0D0B. The piano key distinction is much more subtle in dark mode than light mode.
+      Chrome: Title in light #F0EFE8 ink — clearly readable. Y-axis and X-axis tick labels in #B8B7B0 — readable. Axis labels "Pitch" and "Time (beats)" in light ink — readable. Chord labels in #B8B7B0 — readable. Dynamic markings in #A8A79F — small but legible. Velocity colorbar readable. No dark-on-dark failures detected.
+      Data: Note rectangle colors are identical to light render (#009E73 to #4467A3 gradient) — Imprint data colors are theme-independent, confirmed. The "← climax" annotation in #AE3030 is visible against the dark background. Measure and beat grid lines are visible as slightly lighter/darker lines.
+      Legibility verdict: PASS — all text readable with appropriate light-on-dark chrome. Minor note: black-key row distinction (#0D0D0B vs #1A1A17 background) is barely perceptible in dark mode.
   criteria_checklist:
     visual_quality:
-      score: 26
+      score: 29
       max: 30
       items:
       - id: VQ-01
@@ -59,82 +67,90 @@ review:
         score: 7
         max: 8
         passed: true
-        comment: Title 12pt, axis labels 10pt, tick labels 8pt all explicit and readable.
-          Chord labels (3.5mm) and dynamic markings (3.0mm) readable at full canvas
-          but may be borderline at mobile scale.
+        comment: 'All font sizes explicitly set (title 12pt, axis labels 10pt, tick
+          labels 8pt, geom_text annotations 3.5-4mm). All text readable in both themes.
+          Minor: dynamic markings (INK_MUTED at size=3.5mm) are at the minimum viable
+          size but still legible.'
       - id: VQ-02
         name: No Overlap
-        score: 5
+        score: 6
         max: 6
         passed: true
-        comment: No hard overlaps. Climax annotation (x=7.6, y=73) is tight against
-          IV(F) chord label (x=6, y=73.8) creating crowded top margin without actual
-          collision.
+        comment: No overlapping text or data elements. Chord labels well-separated
+          at measure midpoints. Dynamic markings well-placed below piano roll. Climax
+          annotation positioned above C5 note with adequate clearance.
       - id: VQ-03
         name: Element Visibility
-        score: 5
+        score: 6
         max: 6
         passed: true
-        comment: 'Note rects well-defined with INK borders. Velocity gradient reads
-          clearly. Piano key row contrast in dark theme is very faint (#212120 vs
-          #141413 over #1A1A17).'
+        comment: Note rectangles clearly visible in both themes with dark border outline.
+          Varying widths (duration) and colors (velocity) clearly distinguishable.
+          35 notes at appropriate scale.
       - id: VQ-04
         name: Color Accessibility
         score: 2
         max: 2
         passed: true
-        comment: Imprint sequential cmap (#009E73->#4467A3) is CVD-safe. No red-green
-          as sole signal.
+        comment: Velocity colormap green-to-blue (imprint_seq) is CVD-safe (green
+          and blue distinguish well under deuteranopia/protanopia). No red-green sole
+          signal. Dark note outlines provide redundant structural encoding.
       - id: VQ-05
         name: Layout & Canvas
-        score: 3
+        score: 4
         max: 4
         passed: true
-        comment: 3200x1800 correct. Good overall proportions. Minor crowding in top
-          margin (chord labels + climax annotation) and bottom margin (dynamic labels
-          between piano roll and x-ticks).
+        comment: 3200x1800 landscape. Piano roll fills the canvas well with appropriate
+          margins. Colorbar legend positioned right. coord_cartesian ensures note
+          rectangles don't overflow. No clipping detected at any edge.
       - id: VQ-06
         name: Axis Labels & Title
         score: 2
         max: 2
         passed: true
-        comment: Title matches required format exactly. X=Time (beats) with units,
-          Y=Pitch with note-name tick labels (C3-C5).
+        comment: Title 'piano-roll-midi · python · plotnine · anyplot.ai' correct
+          format. X-axis 'Time (beats)' — descriptive with units. Y-axis 'Pitch' with
+          note names on ticks (C3, G3, C4, G4, C5). All informative.
       - id: VQ-07
         name: Palette Compliance
         score: 2
         max: 2
         passed: true
-        comment: 'scale_fill_gradient(low=#009E73, high=#4467A3) is exact imprint_seq
-          cmap. Backgrounds #FAF8F1/#1A1A17. All chrome theme-adaptive.'
+        comment: 'Continuous velocity data uses imprint_seq (low=#009E73, high=#4467A3)
+          — correct. Background #FAF8F1 light / #1A1A17 dark — correct. Data colors
+          identical across both renders. All chrome tokens theme-adaptive. Piano key
+          shading colors are structural (not data colors) — acceptable.'
     design_excellence:
       score: 14
       max: 20
       items:
       - id: DE-01
         name: Aesthetic Sophistication
-        score: 5
+        score: 6
         max: 8
         passed: true
-        comment: 'Well above generic defaults: custom piano-key background rows, differentiated
-          beat/measure lines, dashed octave boundaries, chord symbols, dynamic markings.
-          Thoughtful DAW-inspired design.'
+        comment: 'Strong design clearly above defaults: piano key alternating backgrounds
+          with theme adaptation, chord progression labels, dynamic markings, climax
+          annotation in semantic red, three-tier grid hierarchy. Shows genuine domain
+          expertise and intentional visual design.'
       - id: DE-02
         name: Visual Refinement
         score: 4
         max: 6
         passed: true
-        comment: theme_void() removes superfluous chrome. Background rows replace
-          panel background meaningfully. Beat/measure visual hierarchy is deliberate.
-          Legend uses ELEVATED_BG frame.
+        comment: theme_void() as base removes all default chrome. Three-tier grid
+          hierarchy (dotted beat lines 0.25, solid measure lines 0.5, dashed octave
+          lines 0.35) is well-executed visual refinement. Clean colorbar, proper whitespace
+          (plot_margin=0.02). Above minimal-refinement default.
       - id: DE-03
         name: Data Storytelling
-        score: 5
+        score: 4
         max: 6
         passed: true
-        comment: Climax annotation guides viewer to musical high point. Chord progression
-          labels (I->IV->V->I) frame harmonic arc. Dynamic markings (mf->ff->dim.->p)
-          narrate intensity curve. Multiple storytelling layers working cohesively.
+        comment: 'Visual hierarchy: I-IV-V-I chord labels create harmonic narrative.
+          mf→ff→dim→p dynamic markings tell the intensity arc. Climax annotation with
+          red color draws the eye to the musical peak. Good storytelling but melody/bass
+          distinction not visually reinforced (no size/alpha differentiation).'
     spec_compliance:
       score: 15
       max: 15
@@ -144,29 +160,34 @@ review:
         score: 5
         max: 5
         passed: true
-        comment: 'Correct MIDI piano roll: horizontal rectangles by pitch (y) and
-          time onset (x), width=duration.'
+        comment: 'Correct piano roll visualization: horizontal rectangles for notes,
+          Y=pitch, X=time, width=duration, color=velocity. Piano keyboard row structure
+          in background.'
       - id: SC-02
         name: Required Features
         score: 4
         max: 4
         passed: true
-        comment: Y-axis note names, alternating key shading, beat+measure grid lines,
-          velocity sequential colormap, pitch range auto-fit — all present.
+        comment: 'All required features: note names on Y-axis (C3/G3/C4/G4/C5), alternating
+          black/white key backgrounds, beat grid (dotted) and measure grid (solid),
+          velocity colormap (sequential green-to-blue), pitch range auto-fitted with
+          margin.'
       - id: SC-03
         name: Data Mapping
         score: 3
         max: 3
         passed: true
-        comment: X=time beats, Y=MIDI pitch as note names, color=velocity, width=duration.
-          All 4 data dimensions mapped correctly.
+        comment: X=time in beats, Y=pitch (MIDI numbers 48-72 with note names), color=velocity,
+          width=duration. All 4 measures (16 beats) visible. Chord progression and
+          melody fully shown.
       - id: SC-04
         name: Title & Legend
         score: 3
         max: 3
         passed: true
-        comment: Title piano-roll-midi · python · plotnine · anyplot.ai exact match.
-          Velocity colorbar with 60/80/100/120 breaks.
+        comment: Title 'piano-roll-midi · python · plotnine · anyplot.ai' matches
+          required format exactly. Velocity colorbar labeled correctly. Y-axis displays
+          note names (spec requirement for human-readable pitch labels).
     data_quality:
       score: 15
       max: 15
@@ -176,23 +197,27 @@ review:
         score: 6
         max: 6
         passed: true
-        comment: 'All piano-roll dimensions: pitch, onset, duration, velocity. Musical
-          annotation layers demonstrate full use of the format.'
+        comment: 'Shows all piano roll features: chord voicings (multiple simultaneous
+          notes), melodic runs (eighth/quarter notes), varying note durations, full
+          velocity range (60-115), bass + melody register coverage, 4-measure phrase
+          structure with chord progression.'
       - id: DQ-02
         name: Realistic Context
         score: 5
         max: 5
         passed: true
-        comment: Classic C->F->G->C chord progression with realistic MIDI voice leading,
-          velocity dynamics (mf->ff->dim.->p), melodic climax at C5. Musically plausible
-          and content-neutral.
+        comment: I-IV-V-I chord progression (C→F→G→C) is a canonical Western music
+          structure. Velocity values (60-115) are realistic for a mf to ff musical
+          phrase. Note durations (0.5-3.0 beats) are musically plausible. The climax
+          at measure 2 (ff, C5) is musically authentic.
       - id: DQ-03
         name: Appropriate Scale
         score: 4
         max: 4
         passed: true
-        comment: 35 notes over 16 beats (4 measures) within 20-200 note / 4-16 measure
-          spec range. Pitch C3-C5 (MIDI 48-72) is realistic.
+        comment: MIDI values 48-72 (C3-C5) appropriate range for a 2-octave piano
+          arrangement. Velocity 60-115 within MIDI range (0-127). 16 beats = 4 measures
+          in 4/4 time. All values factually correct for MIDI piano roll context.
     code_quality:
       score: 10
       max: 10
@@ -202,53 +227,64 @@ review:
         score: 3
         max: 3
         passed: true
-        comment: Flat script, no unnecessary functions or classes.
+        comment: 'Flat script: tokens → data → derived data → plot layers → save.
+          No functions or classes. Clear organization with comments marking sections.'
       - id: CQ-02
         name: Reproducibility
         score: 2
         max: 2
         passed: true
-        comment: np.random.seed(42) set.
+        comment: np.random.seed(42) set. Data is fully hardcoded tuples — deterministic
+          regardless of seed. Fully reproducible.
       - id: CQ-03
         name: Clean Imports
         score: 2
         max: 2
         passed: true
-        comment: All imports used, no dead imports detected.
+        comment: 'All imports from plotnine are used: ggplot, aes, geom_rect, geom_segment,
+          geom_text, geom_vline, annotate, scale_fill_gradient, scale_x_continuous,
+          scale_y_continuous, coord_cartesian, labs, guide_colorbar, theme, theme_void,
+          element_text, element_line, element_rect. numpy, pandas, os all used.'
       - id: CQ-04
         name: Code Elegance
         score: 2
         max: 2
         passed: true
-        comment: Clear readable structure, well-named variables, no fake UI elements.
+        comment: Pythonic, appropriate complexity for the visualization. No fake interactivity.
+          List comprehensions for bg_rows and label generation. Multiple DataFrames
+          for different geom layers is the correct plotnine pattern.
       - id: CQ-05
         name: Output & API
         score: 1
         max: 1
         passed: true
-        comment: Saves as plot-{THEME}.png with correct canvas settings (dpi=400,
-          width=8, height=4.5).
+        comment: Saves as plot-{THEME}.png using plot.save() with correct dpi=400,
+          width=8, height=4.5, units='in'. Current plotnine 0.15.5 API.
     library_mastery:
       score: 8
       max: 10
       items:
       - id: LM-01
         name: Idiomatic Usage
-        score: 4
+        score: 5
         max: 5
         passed: true
-        comment: Correct grammar-of-graphics layering. Multiple independent dataframes
-          passed to individual geoms idiomatically. coord_cartesian for precise axis
-          control is the right plotnine pattern.
+        comment: 'Expertly uses plotnine''s grammar of graphics: multiple geom layers
+          on different data frames (bg_df for backgrounds, df for notes, measure_labels,
+          dynamic_labels, octave_lines), scale functions for both axes and fill, coord_cartesian
+          for clipping, guide_colorbar for legend, fine-grained theme() customization.
+          Idiomatic plotnine.'
       - id: LM-02
         name: Distinctive Features
-        score: 4
+        score: 3
         max: 5
         passed: true
-        comment: 'Uses plotnine layer composition: geom_rect for both background rows
-          and note rects (two datasets), geom_vline + geom_segment + geom_text + annotate
-          in one pipeline. guide_colorbar(nbin=200) for smooth gradient. scale_y_continuous
-          with fully custom breaks/labels for pitch names.'
+        comment: 'Uses some plotnine-specific features: multiple data frame layers
+          in a single ggplot() chain, guide_colorbar() for colorbar customization,
+          annotate() for text overlays, element_text/element_rect/element_line theme
+          components. The piano roll structure itself could be replicated in matplotlib
+          — no uniquely-plotnine statistical transformation (stat_*, position_*, facet_*)
+          is leveraged.'
   verdict: APPROVED
 impl_tags:
   dependencies: []
@@ -265,4 +301,3 @@ impl_tags:
   - minimal-chrome
   - custom-colormap
   - edge-highlighting
-  - grid-styling