A visualization tool that turns data into specifications for charts, tables, graphs, flow diagrams, tile maps, and geographic maps.

Use it to create OpenChart specifications, data tables, network graphs, Sankey diagrams showing flows, tile maps, and maps based on geographic data.

It helps you choose suitable visual forms and produce structured chart instructions without designing each visualization from scratch.

openchart — Skill by tryopendata

Install

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.

agentmods

npx agentmods add skills/tryopendata/skills/openchart

Any agent

npx skills add tryopendata/skills --skill openchart

Clone the repo

git clone --depth 1 https://github.com/tryopendata/skills

Made for: Claude Code, Codex.

Per session 138 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 11,479 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00138	$0.11479
Opus 5	$0.00069	$0.05740
Sonnet 5	$0.00028	$0.02296
Haiku 4.5	$0.00014	$0.01148

Measured 3d ago against content hash 8f9340b983b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openchart 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 3d 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.

plugins/openchart/skills/openchart/SKILL.md · 473 lines

How it starts

The opening of the file, as written. The whole thing — 473 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Data Visualization with OpenChart

Note: SVG design capabilities (logos, icons, graphics) have moved to the opendesign plugin. Install with /plugin install opendesign@opendata-skills.

Source of truth: load the types first

Before authoring or modifying a spec, load the OpenChart type definitions. They are the canonical source for field shapes, enums, and defaults. This skill complements the types — it does not replace them. When this skill and the types disagree, the types win.

Try these locations in order; stop at the first one that resolves:

Installed package (most common): node_modules/@opendata-ai/openchart-core/dist/index.d.ts. The full chart, table, graph, sankey, tilemap, and map spec surface is rolled into this single bundled .d.ts.
Source repo (if you're working in the openchart monorepo): packages/core/src/types/spec.ts and packages/core/src/types/layout.ts. JSDoc comments here are richer than the bundled .d.ts.
Published CDN (no local install, network available): https://unpkg.com/@opendata-ai/openchart-core/dist/index.d.ts (redirects to the latest published version).
GitHub raw (if unpkg is unreachable, or you want the richer source JSDoc): https://raw.githubusercontent.com/tryopendata/openchart/main/packages/core/src/types/spec.ts. For version-exact types, pin to a release tag instead of main: https://raw.githubusercontent.com/tryopendata/openchart/core-v<version>/packages/core/src/types/spec.ts, matching <version> to the installed @opendata-ai/* package version. Note main may document unpublished surface.
Fallback: if none of the above are reachable (no filesystem, no network fetch), use the type sketches in this skill and flag the uncertainty in your response so the user knows you authored without canonical types.

The names worth grepping for once you have a types file open: ChartSpec, TableSpec, GraphSpec, SankeySpec, TileMapSpec, GeoMapSpec (+ GeoMapGeo, GeoMapPointsLayer), MarkType (the 16-mark union), Encoding, EncodingChannel, MarkDef, Chrome, Metric, EndpointLabelsConfig, Annotation (union), TextAnnotation, RangeAnnotation, RefLineAnnotation, LegendConfig, LabelSpec, SeriesStyle, AnimationSpec, ThemeConfig, A11yConfig, SeriesSearchConfig, YouDrawItConfig.

Read the full file on GitHub · 473 lines

Files

What ships with it

37 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

3d ago First seen · 473 lines · 138 tokens per session scan A 8f9340b983b8

Subscribe to this mod's changes

openchart is a skill published in the GitHub repository tryopendata/skills (127 stars, last pushed 1mo ago), licensed MIT. It adds 138 tokens to every session and 11,479 once invoked, about $0.0007 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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