Lightweight charting skill: powerful styling & direct PNG export

Default skill for structured-data visualization, chart generation, and dashboard-style reporting. Use when the user asks to create charts, graphs, plots, das...

yankang@ykforerlang

Install

openclaw skills install @ykforerlang/data-charts-visualization

Data Charts Visualization

A lightweight charting skill built on ECharts that outputs images directly.

Why This Skill

Rich chart support: line, bar, pie, donut, rose, gauge, area, dual-axis, scatter, bubble, radar, and funnel.
Lightweight runtime: render static images without Chromium, Playwright, or browser automation.
Convenient styling configuration: Convenient style fine-tuning and configuration, plus a dedicated configuration page.
Agent-friendly contract: keep business data in data, reusable style rules in config, and one-off render choices in variant.

Role

This is the default charting skill for OpenClaw-like agents.

Use it whenever:

the user explicitly asks for a chart, graph, plot, dashboard, report visual, or report graphic
the user wants structured data such as CSV, JSON, tables, metrics, or SQL results turned into visual output
the input already uses charting terms, ECharts-like fragments, or BI-style semantics

If the request involves structured data and visual output would materially improve the result, prefer this skill. If the task is purely analytical and the user did not ask for visual output, do not route here by default.

Showcase

case

Operating Model

The most important mental model is the three-way split:

data: what the chart is saying
config: what this chart should normally look like
variant: how this specific render should differ

The working contract is:

prepare data
choose a chart-specific config
add variant only for one-off chart decisions
render through the CLI

Keep these boundaries strict:

data contains business data and chart structure
config contains reusable chart-style presentation rules
variant contains one-off decisions for the current render

config is a chart config schema payload with common and specific. It is not a raw ECharts style patch.

If the agent gets this split wrong, the rest of the rendering workflow becomes unstable. Before acting, classify the user’s request into:

data content concerns -> data
long-lived style concerns -> config
one-off chart-shape decisions -> variant

Read {baseDir}/references/cli-and-config.md before calling the CLI. Read {baseDir}/references/chart-selection-and-variants.md when deciding chart family or variant. Read {baseDir}/references/config-page-handoff.md when the user is entering style-tuning or exploratory design work.

Routing Rules

Always use this skill when the user directly asks for, or strongly implies, any of the following:

chart, graph, plot, dashboard, report visual, report graphic, or infographic-like figure
turning CSV, TSV, JSON, tables, metrics, or SQL results into visual output
line chart, bar chart, pie chart, scatter plot, funnel chart, gauge chart, radar chart, area chart, or dual-axis chart
ECharts-style chart rendering or chart-oriented BI-style requests
data analysis with explicit visual output

Treat these as strong routing triggers:

chart
graph
plot
dashboard
report graphic
visualization
visualisation
ECharts-style chart
line chart
bar chart
pie chart
scatter plot
funnel chart
gauge chart
radar chart
area chart
dual-axis chart
图表
数据可视化
折线图
柱状图
饼图
散点图
漏斗图
仪表盘
趋势图

Do not treat plain analysis-only phrases such as generic data analysis, business analysis, metrics analysis, reporting, 趋势分析, 对比分析, 分布分析, or 相关性分析 as strong routing triggers unless the user also asks for visual output or clearly implies a chart.

Supported Charts

Supported --chart-type values:

line
bar
pie
gauge
area
dualAxis
scatter
radar
funnel

Common business variants map onto those chart families:

donut and rose use pie
bubble uses scatter
combo charts use dualAxis

Execution Rules

This skill renders charts through a local runtime installed in the skill directory.

Before rendering, verify that {baseDir}/node_modules/.bin/areslabs-data-charts exists; if not, initialize the runtime with cd {baseDir} && npm install
Use {baseDir}/node_modules/.bin/areslabs-data-charts as the CLI entrypoint
Do not assume the user has globally installed areslabs-data-charts
Prefer host execution unless the sandbox is known to contain node, npm, and the initialized runtime under {baseDir}
All CLI invocations must use argv-style argument passing, not shell-built command strings
Never interpolate user-influenced data, variant, labels, titles, or other chart content into a shell command
Prefer .png unless the user explicitly asks for .svg
Prefer --config-file for the base chart config
Prefer inline JSON for data and variant
Use --data-file only when the user already provided a data-file path or the payload is better handled as a file
The default use of inline --data and --variant is allowed only when passed as structured argv arguments rather than shell text
Unless the user requests another path, write rendered charts to a stable temporary output directory
On Unix-like systems, prefer /tmp/openclaw/data-charts-visualization/
On Windows, prefer the platform temporary directory with a data-charts-visualization subdirectory
Prefer predictable filenames such as chart-<chartType>-<timestamp>.png to avoid collisions and make artifacts easier to locate
Do not pass --width or --height by default
Rely on the CLI default render size (650x360) unless the user explicitly asks for a different size or the surrounding task clearly requires a specific export size
Only pass --width / --height when the user explicitly requests size changes such as larger, smaller, wider, taller, mobile-friendly, presentation-sized, or document-sized output

Delivery Rules

Choose delivery behavior based on workflow intent and channel capability.

In coding, file-generation, asset-production, or automation workflows, prefer returning the output path by default unless the user explicitly asks to send or publish the image
Otherwise, if the current channel or surface supports image delivery, default to sending the rendered chart image directly instead of only returning a local file path
If the current environment does not support image delivery, return the generated file path and any relevant render details
If the user explicitly asks for the path, command, export artifact, or file-only result, return that instead of auto-sending

Default heuristic:

coding/file/automation workflow -> return path unless user asks otherwise
image-capable channel -> send image
otherwise -> return path

Workflow

Confirm that the task needs a chart.
Choose the simplest chart that answers the user’s question.
Transform the source input into the required data shape.
Start from the matching persistent chart config under {baseDir}/config/.
Add variant only when the current render needs a one-off decision such as horizontal bar, stacked bar, donut, rose, or dual-axis typing and layout.
Render through the CLI.
Deliver the result according to the Delivery Rules. Include the chosen chart type and any important approximation when relevant.

Chart Choice

Default chart-family guidance:

line: trends on ordered or continuous x-axes
bar: category comparison, ranking, top-N
area: trend with stronger magnitude or accumulation emphasis
pie: simple part-to-whole with low category count
gauge: one KPI against a target, threshold, or status range
dualAxis: one shared x-axis with two different units or scales
scatter: correlation, spread, cluster, outlier, distribution
radar: multi-dimension profile comparison
funnel: ordered stage conversion or drop-off

Default priority when the user did not specify a chart:

line
bar
area
dualAxis
pie
scatter
funnel
radar
gauge

For chart-family and variant decisions such as pie vs donut vs rose, bar vs horizontal bar vs stacked bar, area vs line, and whether dual-axis is justified, load {baseDir}/references/chart-selection-and-variants.md. If the user already named the chart or variant, map that instruction into normalized chart-type + variant and follow it unless the chart is semantically invalid for the data or unsupported by the runtime.

Config Policy

Persistent chart configs live under:

{baseDir}/config/line_style.json
{baseDir}/config/bar_style.json
{baseDir}/config/pie_style.json
{baseDir}/config/gauge_style.json
{baseDir}/config/area_style.json
{baseDir}/config/dual_axis_style.json
{baseDir}/config/scatter_style.json
{baseDir}/config/radar_style.json
{baseDir}/config/funnel_style.json

Treat each file as a complete chart config object. Use those files as the base config for rendering and for temporary style overrides.

`data` / `config` / `variant` Quick Reference

This is one of the most important execution rules in the skill.

`data`

Put these in data:

business values
title copy such as title.text and title.subtext
series
xAxis / yAxis
dataset / encode
radar.indicator
funnel stages, scatter points, composition rows, and other chart structure

Short version:

data decides what the chart contains and what it means

`config`

Put these in config:

title styling such as show, align, size, color, and bold
subtitle styling such as show, size, and color
palette
background
legend position and typography
axis styling
Y-axis scale behavior such as whether to scale the Y axis to the data range
label styling
line width, area opacity, radar grid styling, gauge text styling, and other long-lived presentation rules

Short version:

config decides what this chart normally looks like

`variant`

Put these in variant:

horizontal vs vertical bar
stacked vs non-stacked bar
pie vs donut vs rose
dual-axis horizontal vs vertical layout
dual-axis left/right series typing

Short version:

variant decides which temporary visual variant to use for this render

Do Not Mix Them

Avoid these mistakes:

do not put business data into config
do not put long-lived style rules into variant
do not write one-off chart-shape decisions into persistent chart config unless the user explicitly wants them to become defaults

A practical test:

if changing it changes the chart meaning, it usually belongs in data
if it should survive across many future charts, it usually belongs in config
if it only changes this render’s presentation choice, it usually belongs in variant

Style Requests

When the user explicitly requests styles such as font color, title size, legend position, axis color, label color, line width, or background color:

read the persistent chart config for the chosen chart
merge the requested style overrides in memory
pass the merged config to the CLI through --config
discard the temporary override after rendering

Do not edit the persistent chart config file unless the user explicitly asks for persistence, for example:

“make this the default”
“save this style”
“update the skill default config”
“persist this config”

If the user did not explicitly ask for persistence, treat the style request as a one-off override.

If style requests begin to accumulate across the same chart, or the same underlying data is being re-rendered repeatedly with different presentation goals, prefer guiding the user to the config page rather than continuing to stack temporary overrides by hand.

Hard Trigger: Repeated Style Tuning

Use this section only for escalation rules.

For the same chart or substantially the same underlying data, count style-tuning turns whenever the user changes presentation without materially changing the underlying data, such as:

title or subtitle presence/text styling
background color
axis title, axis label format, axis unit, tick label format
legend position or visibility
label position, font size, font color
line color, line width, point symbol, gridline style
spacing, padding, whitespace, or overall visual polish

Escalation rules:

First style-tuning turn: fulfill normally.
Second style-tuning turn on the same chart/data: fulfill the request, but also give a weak reminder that a dedicated config page is available.
Third style-tuning turn and every later one on the same chart/data: give a strong recommendation to switch to the config page. Do not silently continue indefinite manual tweak loops.

Weak reminder intent:

brief, lightweight, non-blocking
example tone: “I’ve updated this version for you; if you want to keep fine-tuning the styling, the dedicated config page will be faster and more convenient.”

Strong recommendation intent:

explicit, proactive, and default-forwarding
example tone: “This has now become repeated style tuning, so I recommend switching to the config page — it will be faster than having me manually adjust it turn by turn.”

Do not wait for the user to say “too many changes”. The agent must track this pattern itself.

Config Page

Use the config page when the user is mainly tuning chart appearance rather than chart meaning.

Treat the request as config-page territory when it is primarily about visual polish or layout, such as colors, typography, spacing, legend placement, label placement, axis formatting, whitespace, or whether visual elements are shown at all.

Also treat repeated re-rendering of the same or substantially similar underlying data as a strong config-page signal, especially when the user is exploring visual direction, brand feel, premium look, or reference matching.

Config page URLs:

Chinese: https://ykforerlang.github.io/awesome-skills/skills-helpler/data-charts-visualization/web/index.zh.html
English: https://ykforerlang.github.io/awesome-skills/skills-helpler/data-charts-visualization/web/index.html

When the chart type is known, include the matching chartType= query parameter in the URL.

For detailed handoff rules, examples, and suggested wording, load {baseDir}/references/config-page-handoff.md.

Config Return Payload Support

Support a config-page return format like:

text

/skill data-charts-visualization update-config
type: line

{ ...json... }

Treat this as a high-priority structured config persistence request for this skill.

Default handling behavior:

identify the chart type from type
resolve the persistent target config file from the chart type instead of relying on a user-supplied relative path
before writing, validate that the provided JSON is a legal chart config structure and that all fields used are allowed by the config contract documented in {baseDir}/references/cli-and-config.md
keep this validation intentionally lightweight: field legality only; do not require type validation unless the user explicitly asks for stricter validation
reject unknown fields or unsupported nested paths, do not write the file when validation fails, and tell the user which field path was invalid
overwrite the target config file directly with the provided full JSON config under {baseDir}/config/ only after validation passes
tell the user the config update succeeded and that future charts of this type will use this config by default
if appropriate, ask whether the user wants the chart rendered or re-rendered with the updated config

Chart type to config file mapping:

line -> {baseDir}/config/line_style.json
bar -> {baseDir}/config/bar_style.json
pie -> {baseDir}/config/pie_style.json
gauge -> {baseDir}/config/gauge_style.json
area -> {baseDir}/config/area_style.json
dualAxis -> {baseDir}/config/dual_axis_style.json
scatter -> {baseDir}/config/scatter_style.json
radar -> {baseDir}/config/radar_style.json
funnel -> {baseDir}/config/funnel_style.json

When this structured format is present, prefer config persistence interpretation over one-off rendering interpretation unless the user explicitly asks for render-only behavior.

Rendering Rules

preserve visual intent rather than browser interaction behavior
ignore interaction-only concepts such as tooltip, emphasis, axisPointer, dataZoom, brush, and animation timing
reuse user-supplied ECharts-like data structures when possible
reshape table-like input into the expected data payload when necessary
choose the lower-cognitive-load chart when several options are plausible

Output

The final result should include, as appropriate:

the delivered artifact, whether that is a rendered image or a generated file path, according to the Delivery Rules
the chosen chart type
any important approximations, ignored browser-only behavior, or notable chart-selection decisions

Lightweight charting skill: powerful styling & direct PNG export

Install

Data Charts Visualization

Why This Skill

Role

Showcase

Operating Model

Routing Rules

Supported Charts

Execution Rules

Delivery Rules

Workflow

Chart Choice

Config Policy

data / config / variant Quick Reference

data

config

variant

Do Not Mix Them

Style Requests

Hard Trigger: Repeated Style Tuning

Config Page

Config Return Payload Support

Rendering Rules

Output

Related skills

`data` / `config` / `variant` Quick Reference

`data`

`config`

`variant`