Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add joe-broadhead/open-cowork --skill chart-creatorgit clone --depth 1 https://github.com/joe-broadhead/open-coworkWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/joe-broadhead/open-cowork/chart-creator)<a href="https://agentmods.dev/skills/joe-broadhead/open-cowork/chart-creator"><img src="https://agentmods.dev/badge/skills/joe-broadhead/open-cowork/chart-creator/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/joe-broadhead/open-cowork/chart-creator"><img src="https://agentmods.dev/badge/skills/joe-broadhead/open-cowork/chart-creator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00040 | $0.00921 |
| Opus 5 | $0.00020 | $0.00461 |
| Sonnet 5 | $0.00008 | $0.00184 |
| Haiku 4.5 | $0.00004 | $0.00092 |
Grade A, and why
chart-creator scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Chart Creator
Use this skill when the user asks for a chart, diagram, visual explanation, or chart-ready redesign.
Core Rule
When the charts MCP is available, call the appropriate charts_* tool. Do not merely print a Vega-Lite spec or Mermaid source unless the user explicitly asks for raw source only.
Workflow
- Identify the question the chart must answer.
- Reduce the data to a flat array of objects with clear field names and one row per plotted mark.
- Validate the grain, units, ordering, and category count before plotting.
- Choose the simplest chart that shows the signal without distorting it.
- Call the matching charts MCP tool with complete inline data.
- Explain briefly what the chart shows and any caveat needed to read it correctly.
Tool Choice
charts_line_chart: default for ordered trends over dates, times, weeks, months, versions, or ranks.charts_bar_chart: category comparison or ranking. Use bars for dates only when discrete daily/weekly/monthly magnitudes are the point; keep dates chronological, not value-sorted. For horizontal bars, usexfor the numeric value andyfor the category.charts_area_chart: magnitude or composition over an ordered sequence; use only when filled area helps, not for ordinary single-series trends.charts_scatter_plot: relationship between two numeric measures.charts_pie_chart: simple part-to-whole with a small category count; usedonutfor a cleaner share view.charts_heatmap: intensity by two dimensions.charts_map: geographic points with latitude and longitude fields; use only when location is the primary dimension.charts_histogramorcharts_boxplot: distributions.charts_funnel_chart: ordered stage dropoff.charts_waterfall_chart: additive positive/negative contributions.charts_bump_chart: rank changes over time.charts_streamgraph: centered stacked areas for composition changing over time; avoid when ordinary stacked areas are clearer.charts_calendar_heatmap: daily intensity across weeks/months/years when the calendar pattern matters.charts_bullet_chart: actual vs target with optional qualitative ranges.charts_candlestick_chart: open, high, low, close values across a time axis.charts_sankey: weighted flows between stages or categories.charts_mermaid: process, flow, sequence, or architecture diagrams rather than quantitative charts.charts_custom_spec: only when the standard tools cannot express the needed visual.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 65 lines · 40 tokens per session scan A ae370fddca92
chart-creator is a skill published in the GitHub repository joe-broadhead/open-cowork (11 stars, last pushed 4d ago), licensed MIT. It adds 40 tokens to every session and 921 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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