Plot ML Figure

Worker. Callers own the file and the turn. Do not git end-turn.

Details: references/when.md.

Sequence

1. If a skore report or sklearn Display already plots this, use it. Stop.
2. If interactivity (hover, zoom, pan) is the requirement: Plotly Express. Write <caller-figure-dir>/<slug>.html with include_plotlyjs=True (inline, offline). explore-ml-data uses data_analysis/. Do not overwrite that caller’s owned HTML (e.g. data_analysis_<slug>.html). The caller embeds <iframe src="<slug>.html" width="100%" height="640"></iframe> in its markdown beside the implication. Do not add kaleido unless the user asked to export a static image. No Dash. Do not use a CDN.
3. If the plot is statistical on a tidy DataFrame (distribution, categorical compare, relationship, heatmap, pairplot, facet): seaborn figure-level when a notebook will display it ( displot, relplot, catplot, pairplot, heatmap via FacetGrid / axes only if already on a grid). Not a plt.subplots loop and not a for over columns with a trailing g. One figure-level call as the last expression; facet with col= / col_wrap. Save PNG, leave the figure/grid as the last expression. Never plt.close.
4. If it is a simple Series/DataFrame bar / line / hist / area from the index or a few columns, no statistical overlay: df.plot(...). Save the figure (ax.figure.savefig(...)), leave ax.figure (or the axes) visible. Never plt.close.
5. Else matplotlib. Last resort. In a notebook still save and display; do not plt.close.

Notebook cells: save for the caller markdown and show the figure in the notebook. plt.close is for non-notebook scripts only (evaluate/audit scratch probes if they are not notebooks).

Polars → pandas at the plot boundary. Missing import → add-python-package if installed; else name the package and return. api get before new symbols.

Missing this skill from a caller → that caller one-line skips and still follows this tree.

Stop conditions

• Do not write a long matplotlib script for a hist, box, or bar of a Series.
• Do not load choose-python-library for matplotlib vs seaborn vs plotly.
• Do not pixi add / uv add / env add.
• Do not install plotly on the default EDA path.
• Do not plt.close a figure that should appear in a notebook.