Adding LLM docs ​

chartjs2img llm prints a ~1400-line Markdown reference that teaches an LLM how to write Chart.js configs for chartjs2img. Each section lives in one src/llm-docs/*.ts file.

When to add one ​

• You added a Chart.js plugin in Adding a Chart.js plugin. Each plugin gets its own doc file.
• You noticed the existing reference misses a common foot-gun that agents keep tripping on.
• You upgraded a plugin version and its option shape changed.

File shape ​

A llm-docs/*.ts file is a single-purpose ESM module that exports a string called doc:

// src/llm-docs/plugin-example.ts
export const doc = `
## Example plugin (chartjs-plugin-example)

<one-paragraph summary of what the plugin does>

### Options

| Option                                | Type     | Default | Description              |
| ------------------------------------- | -------- | ------- | ------------------------ |
| \`options.plugins.example.enabled\`   | boolean  | \`false\` | Master toggle         |
| \`options.plugins.example.color\`     | string   | -       | CSS color              |

### JSON example

\`\`\`json
{
  "type": "bar",
  "data": { "labels": ["A"], "datasets": [{ "data": [1] }] },
  "options": {
    "plugins": {
      "example": { "enabled": true, "color": "#f39c55" }
    }
  }
}
\`\`\`

### Caveats

- \`enabled: true\` is required; the plugin is off by default.
- Does not support \`type: "treemap"\`.
`

Escaping rules:

• The file is a template literal, so you escape backticks (\`).
• Inside code-fence JSON, the template literal's \n becomes a real newline — you're just writing Markdown inside a JS string.
• TypeScript is not type-checking the Markdown; keep it consistent by hand.

Register it ​

src/llm-docs/index.ts is the aggregator:

import { doc as pluginExample } from './plugin-example'

const docs = [
  // ...existing entries...
  pluginExample,
]

Order matters — getLlmDocs() joins entries with \n\n in array order. Current convention:

1. usage (always first — sets context)
2. chartjsCore
3. Visual plugins (datalabels, annotation, zoom, gradient)
4. Chart-type plugins (treemap, matrix, sankey, wordcloud, geo, graph, venn)
5. Date adapter (adapterDayjs) last

Slot your new entry into the matching group.

Conventions ​

Headings. Start each file with ## <plugin display name> (H2, not H1 — the bundle has no top-level H1). Sub-sections use H3.

Option tables. One big table per plugin. Put the full path in backticks (options.plugins.foo.bar). Type column is free-form (prose is fine: "function or string"). Mark required fields by writing *required* in the Default column.

Examples. Always include at least one working JSON example. Keep data tiny — 2-3 points is enough to show the shape. The example should be copy-pasteable into chartjs2img render.

Caveats. A bullet list of things LLMs keep getting wrong. Lead with the most common. "This plugin must be explicitly enabled" is a common first bullet.

No callbacks / functions. Chart.js options accept functions (ticks.callback, etc.) in the runtime API, but the HTTP/CLI input is JSON. Mention when a plugin can't be fully expressed in JSON.

Avoid unnecessary mentions of chartjs2img. The doc is meant to teach Chart.js config, not chartjs2img internals. Keep plugin docs transferable.

Verify ​

# 1. Type check
bun run typecheck

# 2. Print and eyeball
bun run cli -- llm | less

# 3. Grep for your new section
bun run cli -- llm | grep -A 20 "Example plugin"

# 4. Check total length (a reasonable doc is ~30-200 lines per plugin)
bun run cli -- llm | wc -l

What NOT to put here ​

• Release notes / changelog. This is evergreen reference, not a history.
• Server operations. Env vars, Docker config, etc. belong in the User Guide.
• Claude-specific instructions. Agent Skills files (SKILL.md in plugins/chartjs2img/skills/*) are the right home for those — a context7 / Claude-only audience. chartjs2img llm is host-agnostic.

See the Phase 2-B section of PLAN.md for the upcoming auto-generation of docs/public/llms-full.txt that will concatenate the LLM docs with the guide pages.