chart-image SKILL.md skillA
chart-image from zebbern/claude-code-guide is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add zebbern/claude-code-guide/chart-image@v2.5.1Pins v2.5.1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- zebbern/claude-code-guide
- Path
skills/chart-image/SKILL.md- Versions recorded
- 1
- Latest version
- v2.5.1, committed May 31, 2026
- Size
- 10,628 bytes
- Repository stars
- 4,666
- License
- MIT
Generate publication-quality PNG chart images from data, supporting line, bar, area, candlestick, pie, and heatmap charts. Triggers when the user asks to visualize data, create a graph, plot a time series, or generate a chart for a report, alert, or dashboard. Runs as a lightweight, headless Node.js process without a browser.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Chart Image Generator
Generate PNG chart images from data using Vega-Lite. Perfect for headless server environments.
## Why This Skill?
**Built for Fly.io / VPS / Docker deployments:**
- ✅ **No native compilation** - Uses Sharp with prebuilt binaries (unlike `canvas` which requires build tools)
- ✅ **No Puppeteer/browser** - Pure Node.js, no Chrome download, no headless browser overhead
- ✅ **Lightweight** - ~15MB total dependencies vs 400MB+ for Puppeteer-based solutions
- ✅ **Fast cold starts** - No browser spinup delay, generates charts in <500ms
- ✅ **Works offline** - No external API calls (unlike QuickChart.io)
## Setup (one-time)
```bash
cd /data/clawd/skills/chart-image/scripts && npm install
```
## Quick Usage
```bash
node /data/clawd/skills/chart-image/scripts/chart.mjs \
--type line \
--data '[{"x":"10:00","y":25},{"x":"10:30","y":27},{"x":"11:00","y":31}]' \
--title "Price Over Time" \
--output chart.png
```
## Chart Types
### Line Chart (default)
```bash
node chart.mjs --type line --data '[{"x":"A","y":10},{"x":"B","y":15}]' --output line.png
```
### Bar Chart
```bash
…Read the whole file at its exact version.
How to install
mdr add zebbern/claude-code-guide/chart-image@sha256:7399868d1e6ed219The line at the top of this page pins the label v2.5.1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_ygmddoiuqlwe6yp6)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on May 31, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (10628 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
zebbern/claude-code-guide · 4,666 stars · license MIT · pushed 2026-10-19 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ygmddoiuqlwe6yp6 GET https://markdownregistry.com/api/v1/resolve?ref=zebbern/claude-code-guide/chart-image GET https://markdownregistry.com/api/v1/blob/7399868d1e6ed2193b0294a927078b96e0626dd2ab654826f0b7f8dd8103a873
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.