nyyon-figures
nyyon-figures is a local MCP server that converts editorial content into diagrams and a featured cover image, running entirely on your machine with no network calls required.
Generate figure specs for an article (
figures_for_article) — Get a design brief that maps article content to diagram templates and slots.Get reasoning guidance (
get_reasoning_prompt) — Retrieve a structured prompt explaining how to map an article's ideas to the right templates; embed a title/excerpt/body to get a ready-to-use prompt.List all templates (
list_templates) — Browse all 17 diagram templates (contrast, layers, cycle, fanout, columns, grid, funnel, timeline, quadrant, pyramid, venn, venn3, table, pipeline, radial, bigstat, progression) plus their slot schemas.Render a single diagram (
render_figure) — Produce a 2× PNG of any diagram template by supplying the template name and its slot values.Render a featured cover (
render_cover) — Generate a 1200×630 OG/hero image with headline, optional kicker, optional standfirst, and one word highlighted in the accent color.Render a full article set (
render_set) — Batch-render up to 12 diagrams plus an optional cover in a single call.Animate diagrams — Pass
format: "svg"andanimate: trueto get self-animating SVGs with staggered entrances, looping animations, and traveling accent dots — no JavaScript, pure SMIL + CSS.Customize brand theme (
set_themeor environment variables) — Override colors (accent, paper, ink), fonts, wordmark, URL, and SVG logo mark.View active settings (
get_settings) — Inspect the current theme including colors, fonts, canvas sizes, and available environment variables.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@nyyon-figuresRender a set of figures for my article on data pipelines"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
nyyon-figures

A local MCP server that renders editorial diagrams and featured covers from a spec — for any brand, not just nyyon. No network, no model, nothing leaves the machine — the calling assistant does the thinking, this tool does the drawing.
It ships three things:
Templates — 37 parametric, content-agnostic shapes: 17 diagram templates (story shapes) + 20 data-chart templates (
chart_*, real numbers on real scales) + a 1200×630 featured cover, drawn as code (SVG → PNG via resvg at 2×, or animated SVG).Settings — a brand-themeable paper/ink theme with a single accent. Colors, accent, wordmark and URL are all overridable (file or env); it ships with nyyon's look (
#6C5CE7, Inter + JetBrains Mono) as the default.Reasoning prompt — how to map an article to a set of figures (which shape per idea, anchored to the sentence it illustrates, varied across the piece) + a cover, including a chart-selection guide (pick by goal, the Datawrapper method).
The 17 diagram templates
contrast · layers · cycle · fanout · columns · grid · funnel · timeline · quadrant · pyramid · venn · venn3 · table · pipeline · radial · bigstat · progression
Each uses the accent as a signal: the FIG. mark, the primary arrowheads, and the single focal "point" of the diagram (the goal node, the source, the winning quadrant, the apex…).
Related MCP server: nakkas
The 20 data-chart templates
For when the idea is backed by real numbers. Organized by goal, following Datawrapper's chart-types guide:
goal | templates |
change over time |
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shares of a whole |
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relationships |
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Chart craft is enforced in the renderers, not requested of the caller: bars, columns, areas and waffles always start at zero; line ends and bar ends are labeled directly instead of via legends; bubbles and proportional shapes scale by area, never radius; small multiples share one scale; empty or flat data renders a clean labeled frame, never a NaN SVG. Geo maps are deliberately absent (an offline renderer has no shape data): reach for chart_bar or chart_heatmap by region instead.
Showcase — every template
One render of each shape, so you can pick by eye. All drawn by this tool, default theme.
Diagrams
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Data charts
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Animation
Pass format: "svg" + animate: true to render_figure / render_set and you get a self-animating SVG instead of a flat PNG: every element fades in on a staggered entrance, holds, then exits — one smooth 8s loop, forever. The "traveling" shapes (timeline, cycle, radial) also get an accent dot gliding their path. Pure SVG — SMIL <animateMotion> + CSS @keyframes, no JS, no dependencies, and it honors prefers-reduced-motion. Use it for the web/inline; keep PNG for og:images, email, and link previews (animation doesn't survive those, and a rasterized SVG is just its first frame).
Tools
tool | what it does |
| Start here. Article + a |
| List all templates + the cover with their slot schemas. |
| The active theme — colors, fonts, sizes, brand (reflects runtime changes). |
| Adjust the global look — colors / fonts / brand — for all later renders. |
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| A whole article set ( |
Two ways to use it
Article → figures:
figures_for_articlewith the article +design→ follow the returned brief to produce the spec.render_set(orrender_cover) → PNGs written locally; embed them, use the cover as featured/OG. Show the renders.
Ad-hoc one-off — just call render_figure directly, e.g. "a venn of X and Y overlapping Z" → { template: "venn", slots: { left_label: "X", right_label: "Y", overlap_label: "Z" } }. No article needed.
Re-theme anytime with set_theme (or env / src/settings.js).
Install (Claude / MCP)
npm installThen add to your MCP client config:
{
"mcpServers": {
"nyyon-figures": { "command": "node", "args": ["/ABSOLUTE/PATH/nyyon-figures/src/index.js"] }
}
}Or with the CLI: claude mcp add nyyon-figures -- node /ABSOLUTE/PATH/nyyon-figures/src/index.js
Settings & overrides
Edit src/settings.js, or override at runtime via env:
NYYON_FIGURES_ACCENT— accent hex (default#6C5CE7)NYYON_FIGURES_PAPER/NYYON_FIGURES_INK— background / foregroundNYYON_FIGURES_BRAND_NAME— wordmark text on the cover (defaultnyyon)NYYON_FIGURES_BRAND_URL— URL printed on the cover (defaultnyyon.com)NYYON_FIGURES_BRAND_MARK— SVG path (~64×70 box) for the logo mark;""= text-only wordmark + plain accent hubNYYON_FIGURES_OUT— directory for rendered PNGs (default$TMPDIR/nyyon-figures)
So a different brand is one line: NYYON_FIGURES_BRAND_NAME='Acme' NYYON_FIGURES_BRAND_URL='acme.io' NYYON_FIGURES_BRAND_MARK='' NYYON_FIGURES_ACCENT='#0EA5E9'.
Test
npm test # renders one of every template + the cover into tmp-smoke/Available Tools
6 toolsget_reasoning_promptGet the figure-design reasoning promptA
Return nyyon's reasoning prompt for turning an article into a SET of figures + a cover: which template fits which idea, anchoring each to a sentence, and varying shapes. Pass the article (title/excerpt/body_text) to get the full ready-to-use prompt with the article embedded; omit it to get just the rules + template menu. Use the prompt to produce the figure-spec JSON, then call render_figure / render_cover.
| Name | Required | Description | Default |
|---|---|---|---|
| title | No | ||
| excerpt | No | ||
| body_text | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full burden for behavioral disclosure. It states that embedding the article modifies the prompt, but does not mention potential side effects, idempotency, rate limits, or authentication requirements. For a tool that likely has no destructive side effects, this is adequate but not complete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single paragraph of four sentences, front-loaded with the core purpose. Each sentence provides necessary information: what the prompt does, how to pass the article, what to do with the output. It is concise without omitting critical details.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool returns a prompt for figure creation, the description explains the overall workflow and references sibling tools (render_figure, render_cover). It does not describe the output schema or prompt format, but that is reasonable for a prompt-returning tool. It covers the key context for use.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 0%, so the description must compensate. It explains that title, excerpt, and body_text are parts of the article to embed in the prompt, and that omitting all of them yields a different output (rules + template menu). This adds significant meaning beyond the parameter names alone.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states that the tool returns a reasoning prompt for turning an article into figures and a cover, with specific details about template selection and sentence anchoring. It distinguishes itself from sibling tools like render_figure and render_cover by indicating that this tool produces the prompt to guide those subsequent calls.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly tells when to pass article parameters (to get the full prompt) and when to omit them (to get just the rules and template menu). It also provides the downstream workflow: use the prompt to produce figure-spec JSON, then call render_figure/render_cover. This covers both usage scenarios and next steps.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_settingsGet brand settingsB
Return the active brand theme — colors (incl. the accent), fonts, canvas sizes, and the env vars that override them.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided. The description does not disclose behavioral traits such as caching, required permissions, side effects, or rate limits. Being a getter, it is likely non-destructive, but this is not explicitly stated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Single sentence that is directly informative without any fluff. Every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Without an output schema, the description reasonably details the return contents. It covers major aspects of the brand theme but does not specify format or structure.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
No parameters exist, so schema coverage is 100%. The description adds value by listing what the return includes, which goes beyond the empty schema. Baseline for 0 params is 4.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool returns the active brand theme with specific elements (colors, fonts, canvas sizes, env vars). It distinguishes from sibling tools like render_cover and list_templates which are about rendering or listing different resources.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this tool vs alternatives. For a simple getter it may be obvious, but lacks any context about prerequisites or when not to use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
list_templatesList figure templatesA
List every diagram template (16) and the featured cover with their slot schemas. Call this first to learn what shapes exist and exactly which slots each render tool expects.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description fully explains the tool's behavior: it lists templates with slot schemas. It implicitly indicates a read-only, non-destructive operation. However, it could explicitly state that no modifications are made or mention any rate limits, but for a simple list, this is sufficient.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences contain all essential information without fluff. The first sentence immediately states the action, and the second provides usage guidance. Every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given that the tool has no parameters and no output schema, the description is fully complete. It tells the agent what the tool does, what it returns (list of templates with slot schemas), and how it should be used (called first). There is no missing context.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool has zero parameters, so schema coverage is 100% and there is no need for additional parameter semantics. The description does not attempt to add information about non-existent parameters, which is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies the tool's function: lists all diagram templates (16) and the featured cover with their slot schemas. It uses specific verb 'list' and specifies the resource 'diagram templates' and content 'slot schemas'. It distinguishes itself from sibling render tools which have different purposes.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly states when to use the tool: 'Call this first to learn what shapes exist and exactly which slots each render tool expects.' This provides clear guidance on the tool's role as a precursor to render tools, effectively excluding misuse.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
render_coverRender the featured coverC
Render the 1200x630 featured/hero cover (OG ratio): the nyyon wordmark, kit shapes wired to an accent hub, and the headline with one word in the accent colour. Returns the file path.
| Name | Required | Description | Default |
|---|---|---|---|
| title | Yes | The headline (usually the article title). | |
| kicker | No | Short topic label in caps, e.g. "AI-NATIVE MARKETING". | |
| highlight | No | One word/phrase copied exactly from the title to print in the accent colour. | |
| sub | No | One-line standfirst under the headline. | |
| out_path | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses the resolution (1200x630) and return type (file path), but omits critical behavioral traits: side effects (file creation), permissions, error handling, performance, or file format. The description is insufficient for safe agentic use.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, dense sentence that front-loads key information (resolution) and covers core elements. It is concise without being vague. However, it could benefit from breaking into multiple sentences for clarity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no annotations, no output schema, and 5 parameters, the description should be more comprehensive. It mentions output but not file format, naming conventions, or whether it overwrites. The tool's complexity (image rendering) warrants richer context.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 80%, so baseline is 3. The description mentions 'headline with one word in accent colour' which maps to title and highlight, but adds no new parameter semantics beyond what the schema already provides. No improvement over schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states what the tool does: renders a 1200x630 featured/hero cover with specific elements (wordmark, shapes, headline). It also mentions the output (returns file path). However, it does not explicitly distinguish from sibling tools like render_figure or render_set, which may have overlapping purposes.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives. There are no when-to-use or when-not-to-use statements, and no mention of prerequisites or context. This is a significant gap for an AI agent deciding between render_cover, render_figure, or render_set.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
render_figureRender one diagramA
Render a single in-article diagram to a PNG. Provide the template name and its slots (see list_templates for each template's slot schema). Returns the file path. Renders at 2x for crisp output.
| Name | Required | Description | Default |
|---|---|---|---|
| template | Yes | ||
| slots | Yes | ||
| out_path | No | Optional filename or sub-path written INTO the output dir (confined to it). |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses output as file path and 2x rendering for crisp output. However, with no annotations, more information would be beneficial, such as whether it overwrites existing files, idempotency, or required permissions. Still, key behaviors are covered.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three concise sentences with no redundancy. First sentence states purpose, second explains inputs, third describes output and quality. Every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given 3 parameters, no output schema, and no annotations, the description is fairly complete. It covers input requirements, output format, and quality hint. Could mention the output path format or directory confinement, but overall adequate for the tool complexity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema has 33% coverage; the description compensates by referencing list_templates for slot schema and explaining that slots are validated there. However, it does not detail the structure of slots or add meaning beyond the schema for out_path. Adequate but not excellent.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly states it renders a single in-article diagram to PNG. Distinguishes from sibling tools like render_set (multiple) and render_cover (cover image) by specifying 'single' and 'in-article'.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Instructs to provide template name and slots, and references list_templates for slot schema, providing clear context. Does not explicitly state when not to use, but the purpose is well-defined and alternatives are implied by sibling names.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
render_setRender a whole figure set + coverA
Render a full article set in one call: an array of figures (each { template, slots }) plus an optional cover. Returns the list of written paths. Convenience over calling render_figure repeatedly.
| Name | Required | Description | Default |
|---|---|---|---|
| figures | No | ||
| cover | No | ||
| out_dir | No | Optional sub-directory (confined to the output dir) for this set. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full responsibility. It mentions the return value (list of written paths) but does not disclose side effects (e.g., file writing behavior), prerequisites (e.g., output directory existence), or error handling. The absence of such details limits transparency for an AI agent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise, consisting of two sentences that front-load the core purpose and output. Every sentence adds value without redundancy, achieving maximum information density with minimal verbosity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity (nested objects, 3 parameters, no output schema), the description covers the basic intent and structure but lacks details on return value format, error scenarios, and constraints (e.g., max items). It is adequate for a simple tool but not fully self-contained for an AI agent to use confidently without schema inspection.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is low (33%, only out_dir has a description). The tool description adds minimal parameter context beyond what the schema already exposes, such as the structure of figures (template and slots) and cover being optional. It does not explain the semantics of 'slots' or the behavior of the cover fields, leaving the agent to infer from the schema alone.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool renders a full article set in one call, specifying input structure (array of figures plus optional cover) and output (list of written paths). It distinguishes itself from sibling tools by mentioning it is a convenience over calling render_figure repeatedly, making the purpose unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description indicates when to use this tool ('convenience over calling render_figure repeatedly'), implicitly suggesting it is ideal for multiple figures. However, it does not explicitly state when not to use it (e.g., for a single figure or standalone cover) or provide alternative scenarios, leaving some room for ambiguity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
6 tool updates
v0.1.1- First observed
get_reasoning_prompt - First observed
get_settings - First observed
list_templates - First observed
render_cover - First observed
render_figure - First observed
render_set
TDQS
Scored across 6 tools
Each tool has a distinct purpose: reasoning prompt, settings, template listing, and three rendering variants. No overlap in functionality, so an agent can clearly distinguish them.
All tool names follow a consistent verb_noun snake_case pattern (get_, list_, render_). This predictability aids agent selection and code generation.
With 6 tools covering the core workflow (prompt, settings, templates, rendering), the count is well-scoped for figure generation without being too few or excessive.
The tool surface covers the essential workflow: obtaining a prompt, checking settings, listing templates, and rendering figures/covers. A minor gap is the lack of a tool to retrieve or delete rendered files, but this is not critical for typical usage.
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