Chart MPL

Generate PNG/SVG charts (line, bar, hbar, pie, stacked, scatter, area) from CSV data using matplotlib. Use when the user asks to visualize tabular data, produce BI-ready chart images, or compare multiple series.

Generate chart images from CSV files with scripts/chart_mpl.py.

Setup

Create a virtual environment and install matplotlib (one-time):

python3 -m venv ~/.openclaw/workspace/.venv_chart
~/.openclaw/workspace/.venv_chart/bin/pip install matplotlib

Quick start

Run from workspace root:

~/.openclaw/workspace/.venv_chart/bin/python skills/chart-mpl/scripts/chart_mpl.py \
  --csv /path/to/data.csv \
  --xcol Mois \
  --ycol Valeur \
  --kind line \
  --title "Monthly trend" \
  --xlabel "Month" \
  --ylabel "Value"

Output defaults to: ~/.openclaw/workspace/exports/images

Inputs

• --csv path to CSV file
• --xcol column for X axis
• --ycol numeric column(s) for Y axis — comma-separated for multi-series (e.g. Sales,Costs)
• --kind chart type: line, bar, hbar, pie, stacked, scatter, area
• Optional: --delim if auto-detection fails (;, ,, \t, |)
• Optional: --out custom output path (PNG or SVG — format detected from extension)
• Optional: --title, --xlabel, --ylabel
• Optional: --top N show only top N categories by value (bar, hbar, pie, stacked). Multi-series ranks by row total.
• Optional: --sort sort data before plotting: x-asc, x-desc, y-desc, none (default: none)
• Optional: --numfmt number format on Y axis: fr (1,5M) or en (1.5M) — default: fr

Chart types

Kind	Description	Multi-series
line	Line chart with markers	yes
bar	Vertical bar chart (grouped when multi-series)	yes
hbar	Horizontal bar chart (grouped when multi-series)	yes
pie	Pie chart (first Y column only)	no
stacked	Stacked vertical bar (requires 2+ Y)	yes
scatter	Scatter plot	yes
area	Filled area chart	yes

Notes

• Script auto-detects delimiters when possible.
• Script tolerates European and US numeric formats (1 234,56, 1,234.56).
• Non-numeric values in ycol are converted to NaN with a warning.
• Handles BOM-encoded CSV files (utf-8-sig).
• Multi-series charts automatically show a legend and cycle through an 8-color palette.
• Y-axis ticks use human-readable formatting (K, M, G suffixes) with French or English decimals.
• --top N keeps the N highest categories. For pie charts, the remainder is aggregated into an "Other" slice. For bar/hbar/stacked, the rest are excluded.
• Output format (PNG or SVG) is detected from the --out file extension. Default is PNG.

End-to-end flow with SQL skill

1. Export query result to CSV using the mssql skill.
2. Run this script on that CSV.
3. Share the generated PNG path.