chart-generation Capability

Provides: chart-generation Skill: chart-image

Methods

lineChart

Input:

• data: Array of data points (objects with x/y, time/value, or time/price fields)
• title: (optional) Chart title
• groupBy: (optional) Field to group by for multi-series charts
• options: (optional) Additional options
  • dark: boolean - Use dark theme
  • focusRecent: number - Zoom to last N data points
  • showChange: boolean - Show percentage change annotation
  • showValues: boolean - Show value labels on points

How to fulfill:

# Write data to temp file
echo '${JSON.stringify(data)}' > /tmp/chart-data.json

# Generate chart
node /data/clawd/skills/chart-image/scripts/chart.mjs \
  --type line \
  --data "$(cat /tmp/chart-data.json)" \
  --title "${title}" \
  ${options.dark ? '--dark' : ''} \
  ${options.focusRecent ? '--focus-recent ' + options.focusRecent : ''} \
  ${options.showChange ? '--show-change' : ''} \
  ${options.showValues ? '--show-values' : ''} \
  --output /tmp/chart-${Date.now()}.png

Output: { path: string } - Path to the generated PNG file

---

barChart

Input:

• data: Array of objects with label and value fields
• title: (optional) Chart title
• options: (optional) Additional options
  • dark: boolean - Use dark theme
  • showValues: boolean - Show value labels on bars

How to fulfill:

# Write data to temp file
echo '${JSON.stringify(data)}' > /tmp/chart-data.json

# Generate chart
node /data/clawd/skills/chart-image/scripts/chart.mjs \
  --type bar \
  --data "$(cat /tmp/chart-data.json)" \
  --title "${title}" \
  ${options.dark ? '--dark' : ''} \
  ${options.showValues ? '--show-values' : ''} \
  --output /tmp/chart-${Date.now()}.png

Output: { path: string } - Path to the generated PNG file

---

areaChart

Input:

• data: Array of data points
• title: (optional) Chart title
• options: (optional) Same as lineChart

How to fulfill:

node /data/clawd/skills/chart-image/scripts/chart.mjs \
  --type area \
  --data '${JSON.stringify(data)}' \
  --title "${title}" \
  --output /tmp/chart-${Date.now()}.png

Output: { path: string } - Path to the generated PNG file

---

Notes

• All methods output PNG images to /tmp by default
• Use --dark flag between 20:00-07:00 local time for better night-mode visuals
• For time series, data points should have time or x field in ISO format or readable string
• The skill uses Vega-Lite under the hood - see SKILL.md for full options