Fontpool MCP Server

Fontpool

An MCP server for working with type. It searches three font providers as one catalog, tells you what each family actually is — category, use-case tags, the foundry's own description, every variable axis — downloads the real woff2 files into your project, and writes the matching @font-face rules.

Fonts end up self-hosted — no CDN request at runtime, nothing to break when a third party changes a URL. Built on unifont.

The point is not convenience. An AI asked to style a page reaches for Inter or Roboto almost every time, partly because they are the most probable names and partly because they are the ones it knows it can load. Fontpool exists so that there is something to consult instead: 2,168 families, with the category, use-case tags and the foundry's own description of each, of which 218 are not in Google's catalog.

Providers

They are consulted in that order and the first provider that knows a family wins, so Satoshi resolves to the real ITF release rather than a lookalike.

Google carries no unique families — it is wholly contained in Fontsource, which sits ahead of it, so it has never been the provider that actually served an install. It is kept only as a fallback: unifont swallows a provider's own catalog failure, so if Fontsource — and with it jsDelivr — is unreachable, Google still covers about 1,950 families.

Bunny was removed in 1.3.0. It was a Google Fonts mirror and cost nothing to drop: the catalog is 2,168 families with or without it. The 26 retired Google names it was keeping alive — Source Sans Pro, Material Symbols, the Big Shoulders family — are all in Fontsource too, so nothing became unreachable. Its "privacy-first" pitch was never relevant here either: fontpool downloads the file and self-hosts it, so no request reaches any CDN at runtime.

One caveat on the 218 figure: it counts families Google's API does not currently carry, about 26 of which Google once shipped and has since retired rather than never having had. The families that were never Google's number roughly 192.

Adobe Fonts is deliberately excluded. Adobe's terms require their fonts be loaded from Adobe's own CDN through a kit embed, so they cannot be downloaded into a project. A tool that promises self-hosted files cannot honestly serve them, so Adobe is left out rather than half-supported.

Install

Needs Node 20 or newer. No API keys, no accounts.

npx -y fontpool

That is also the command to put in a client config.

Claude Code

claude mcp add fontpool -- npx -y fontpool

Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows:

{
  "mcpServers": {
    "fontpool": {
      "command": "npx",
      "args": ["-y", "fontpool"]
    }
  }
}

Cursor / Windsurf / Zed and other stdio clients

Same shape, in that client's MCP config:

{
  "mcpServers": {
    "fontpool": {
      "command": "npx",
      "args": ["-y", "fontpool"]
    }
  }
}

The skill

SKILL.md ships alongside the server. The tools are no use if the model never thinks to call them, and nothing about writing CSS naturally prompts a pause to go looking — so the skill is what puts a step between "this needs a sans-serif" and typing a font name. Copy it wherever your client reads skills from, or point your agent at it directly.

Tools

list_fonts

Search the catalog. Called with no arguments it describes the catalog's shape rather than dumping 2,168 names, which is how you discover the tag vocabulary:

{}

2168 families:

By category:
  sans-serif: 824
  display: 500
  serif: 379
  handwriting: 369
  monospace: 72
  other: 17
  icons: 8
  slab-serif: 4
  blackletter: 1

Not carried by Google: 218 families (exclude: ["google"] to see only these).

Tags: poster (53), magazine (50), book (37), logo (31), website (29),
banners (28), editorial (23), branding (20), headline (18), app (11),
legible (11), packaging (9), screen (8), code (5), fun (5), …

Variable axes: wght [Weight] (614), ital [Italic] (185), wdth [Width] (97),
opsz [Optical Size] (32), slnt [Slant] (23), ELSH [Element Shape] (15),
CRSV [Cursive] (14), GRAD [Grade] (8), MONO [Monospace] (3), …30 rarer axes

Narrow with category, tag, filter or exclude — listing all 2168 names at
once is rarely the useful answer.

With filters you get a shortlist worth choosing between:

{ "category": "serif", "tag": "editorial" }

6 families (category: serif, tag: editorial):
Bespoke Serif — serif · fontshare · Indian Type Foundry · magazine, poster, book, branding, editorial
Crimson Pro — serif · fontshare+fontsource+google · magazine, publishing, editorial
Gambarino — serif · fontshare · Indian Type Foundry · magazine, poster, book, editorial
Karma — serif · fontshare+fontsource+google · Indian Type Foundry · banners, editorial
Rowan — serif · fontshare · Indian Type Foundry · book, text, legible, editorial
Zodiak — serif · fontshare · Indian Type Foundry · editorial, magazine, book

Results are deduplicated. unifont's own catalog returns the same family once per provider that carries it — 6,124 lines for 2,168 families, about 20k tokens of mostly repetition — so they are collapsed here, with the providers listed per family instead.

font_properties

What a family actually offers, and what it is, before you commit to it. Family names are matched case- and spacing-insensitively, so satoshi and jetbrains mono both resolve.

{ "family": "Satoshi" }

{
  "family": "Satoshi",
  "formats": ["woff2", "woff", "ttf"],
  "styles": ["normal", "italic"],
  "weights": ["300", "400", "500", "700", "900", "300 900"],
  "provider": "fontshare",
  "availableFrom": ["fontshare"],
  "categories": ["sans-serif"],
  "tags": ["logo", "magazine", "branding"],
  "foundry": "Indian Type Foundry",
  "designers": ["Deni Anggara"],
  "description": "Satoshi is a modernist sans serif typeface. Its design combines typically grotesk-style letterforms, with some characters that are quite geometrically-designed…",
  "descriptionSource": "Indian Type Foundry (marketing copy)",
  "variableAxes": {
    "wght": { "name": "Weight", "min": 300, "max": 900, "default": 780 }
  }
}

Variable fonts report their weight as a range, like "300 900" — pass that same string to install_font to get one variable file instead of several static ones.

variableAxes lists every axis the family carries, not just weight, which is often the reason to choose one font over another:

{
  "family": "Recursive",
  "variableAxes": {
    "wght": { "name": "Weight",     "min": 300, "max": 1000, "default": 400 },
    "slnt": { "name": "Slant",      "min": -15, "max": 0,    "default": 0 },
    "CASL": { "name": "Casual",     "min": 0,   "max": 1,    "default": 0,   "step": 0.01 },
    "CRSV": { "name": "Cursive",    "min": 0,   "max": 1,    "default": 0.5, "step": 0.1 },
    "MONO": { "name": "Monospace",  "min": 0,   "max": 1,    "default": 0,   "step": 0.01 }
  }
}

Lowercase tags are the five OpenType-registered axes; uppercase ones are foundry-defined and mean whatever that typeface decided they mean. step is omitted when it is the uninformative default of 1. Filter on any of them with list_fonts { hasAxis: "wdth" } — 97 of the 2,168 families have a width axis, which is not a thing you can find by reading names.

description is the foundry's own copy, fetched from the provider's catalog and flagged as such. It is reliable about the design and enthusiastic about its merits; weigh it accordingly. A miss suggests near matches rather than only reporting failure:

No provider knows 'Intar'. Did you mean: Inter, NTR, Anta, Inder, Zina?

install_font

Downloads the files and writes the CSS.

{
  "family": "Inter",
  "targetDir": "./public/fonts",
  "cssPath": "./src/fonts.css",
  "weights": ["400", "700"],
  "styles": ["normal"],
  "subsets": ["latin", "latin-ext"],
  "urlPrefix": "/fonts"
}

Installed Inter from fontsource.

Files in /Users/you/app/public/fonts:
  inter-400-normal-latin-68f645c6.woff2 (23.1 KB)
  inter-700-normal-latin-5197a7ae.woff2 (23.8 KB)
  inter-400-normal-latin-ext-1bf1f837.woff2 (34.2 KB)
  inter-700-normal-latin-ext-c8d55506.woff2 (35.4 KB)

CSS in /Users/you/app/src/fonts.css: 4 rule(s) added, 0 updated, 0 already
present. Import it, then use:
  font-family: 'Inter', sans-serif;

Make sure fonts is served at /fonts.

Only family, targetDir and cssPath are required. The rest default to weights 400 and 700, style normal, subsets latin and latin-ext, and a urlPrefix of /fonts.

Three details worth knowing:

• urlPrefix is the public path, not the disk path. Files land in targetDir; the CSS references them at urlPrefix. If your static root is public/, then targetDir: "./public/fonts" pairs with urlPrefix: "/fonts".
• A stylesheet nothing imports is reported. Creating fonts.css that no file references is the one failure that looks exactly like success — the files land, the rules are right, and the page still renders in Helvetica. If the new stylesheet is unreferenced anywhere under the workspace root, the result says so and tells you what to add. Prefer a cssPath the project already imports.
• Re-installing is safe. Filenames carry a content hash, and a rule is recognised as the same face when every descriptor but src matches, so a second install updates rules in place instead of stacking duplicates.

A family that exists but lacks the weights you asked for says so, rather than blaming the name:

'Satoshi' exists, but not in the combination you asked for (weights 350;
styles normal; subsets latin, latin-ext). It has weights 300, 400, 500, 700,
900, 300 900; styles normal, italic.

Where metadata comes from

Categories, tags, foundries and descriptions are read from two catalog APIs — Fontshare's 100 families and Fontsource's 2,103 — which between them cover the whole catalog, because Google is itself a subset of Fontsource. Google's public API carries category and nothing else, so it is not consulted.

Variable axes come from a third endpoint, Fontsource's /v1/variable, whose 573 families join onto the catalog by name with nothing left over. Fontshare publishes its own axes too, which is the only way the 65 families unique to it report a weight range at all — it lists one entry per variable style, so a family with a variable roman and italic reports wght twice; those are merged on the range, and default is dropped when the entries disagree rather than picking one arbitrarily.

Axis display names are Google's axis registry, 56 tags, hardcoded rather than fetched: the registry lives inside a 2.7MB payload whose other 2.68MB is the Google font list, and it changes about once a year. A tag added after that was copied passes through unlabelled, with its range intact.

unifont already fetches the two catalog APIs and keeps the full records, then uses them for one thing: choosing serif or sans-serif as a CSS fallback. Rather than fork it, fontpool fetches them again, which costs one request each at first use — three in total, in parallel, on the first tool call.

Fontshare's tags are free text, so they are folded before being exposed — Poster and Posters are one term, casing is normalised, and a tag that is itself the name of a font in the catalog is dropped as a data-entry slip. Metadata is an enhancement, never a precondition: if any of the three endpoints is unreachable, search still works and the result says the metadata is incomplete.

Where it is allowed to write

install_font creates directories and appends to a stylesheet, so its reach is limited to the project:

• When the client advertises a workspace root (most do), relative paths resolve against that root and both paths must stay inside it — symlinks included. Anything that escapes is refused with an error.
• When the client advertises no root, there is nothing to confine against: relative paths are refused outright, and absolute paths are taken at face value and written wherever they point.

Development

npm install
npm test

The suite drives the server as a child process over real stdio JSON-RPC. Most of it hits the live provider APIs and downloads real fonts; set FONTPOOL_SKIP_NETWORK_TESTS=1 to run only the offline tests.

./build.sh packages the same server as a Claude Desktop .mcpb extension in ~/Downloads, and ./build.sh --dev pushes server.mjs straight into an already-installed copy.

Licence

MIT © Travis Valeri