Jinero MCP Server

online.jinero/jinero — a hosted, remote Model Context Protocol server that gives AI agents (Claude, Cursor, Cline, Zed, Gemini CLI…) the design tools of jinero.online: 22 read-only tools for fonts (search, CSS, files, recognition from an image), color math (WCAG contrast, shades, naming, palette extraction), curated palettes, code minify/convert/detect, SVG optimization and SCSS helpers.

• Endpoint: https://jinero.online/mcp (Streamable HTTP)
• Auth: none — anonymous & free, rate-limited at 60 req/min per IP (plus per-tool caps on heavy tools, see below)
• Registry: online.jinero/jinero in the official MCP registry
• Manifest: /.well-known/mcp/server.json
• Human docs: jinero.online/dev/mcp — full reference with example responses

Connect

Claude Code (CLI):

claude mcp add --transport http jinero https://jinero.online/mcp

Claude Desktop / Cursor / Cline (config):

{
  "mcpServers": {
    "jinero": { "type": "http", "url": "https://jinero.online/mcp" }
  }
}

Older stdio-only clients can bridge with npx mcp-remote https://jinero.online/mcp.

Trust & safety

Every tool declares MCP annotations, verifiable in tools/list:

• all 22 tools are readOnlyHint: true and idempotentHint: true;
• submitted code/SVG is parsed and transformed as text — never executed, never stored;
• uploaded images (font recognition, color extraction) are processed in memory and deleted immediately;
• only three tools fetch a user-supplied URL (recognize_font, extract_colors, svg_to_datauri) — marked openWorldHint: true, with SSRF-guarded, size-capped fetches.

A note for automated risk scanners: some directories classify minify_code, convert_code, generate_clamp or recognize_font as "write" tools based on their verbs. They are pure functions — text/math in, text out; nothing on the server or the caller's side is modified. The authoritative signal is the readOnlyHint: true annotation each of the 22 tools declares in tools/list (snapshotted in tools.json).

Rate limits

The whole endpoint is capped at 60 requests/min per IP. On top of that, compute-heavy tools enforce their own per-tool per-IP caps (server v1.4.0+), returned as a clean tool error with a retry hint when exceeded — each cap is also stated in the tool's description:

Tool	Cap	Why
recognize_font	5/min	CNN model inference
extract_colors	10/min	image analysis subprocess
minify_code, convert_code, optimize_svg	30/min	parser subprocesses
svg_to_datauri	30/min	may fetch external URLs

Tests & CI

tests/tools.test.mjs exercises every declared tool against the live endpoint (zero dependencies, Node 20+):

npm test

CI runs the suite on every push and weekly (workflow), and tools.json is a committed snapshot of the live tools/list — schemas and annotations included (npm run update-snapshot to refresh).

Try it without a client

# List all tools
curl -s -X POST https://jinero.online/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

More runnable examples in examples/.

Tool reference

Generated from the live tools/list of the current server version.

Fonts

search_fonts

Search the free font catalog by name, category, style tags, language coverage, variable/monospace flags and style count. Returns a paginated list of families.

read-only · idempotent

Parameter	Type	Description
name	string	Fuzzy name match.
category	string	Comma-separated categories, e.g. 'serif,sans'.
langs	string	Comma-separated language codes, e.g. 'latin,cyrillic' — ALL must be supported.
style	string	Comma-separated style tags, e.g. 'handwriting,condensed' — ALL must match. One of: handwriting, script, display, slab, rounded, condensed, expanded, stencil, pixel, blackletter, outline, retro.
variable	boolean	Only variable fonts.
monospace	boolean	Only monospace fonts.
styles_min	integer	Minimum number of styles.
styles_max	integer	Maximum number of styles.
order	string: likes | downloads | views | name | created_at	Sort field, default 'likes'.
sort	string: asc | desc	Sort direction.
per_page	integer	Results per page (default 24).
page	integer	Page number.

recognize_font

Identify which font is used in an image. Powered by our OWN CNN embedding model, trained on the jinero font catalog — it matches fonts by visual shape/style, so it needs NO OCR and NO text (works for Latin and Cyrillic). Send a tight crop of one line of text as either image_url (public URL) or image_base64 (base64/data-URI, e.g. a local screenshot). The image is processed in memory and deleted immediately — never stored. Returns the most visually similar font families with scores. Fast (~200 ms).

read-only · idempotent · fetches external URLs

Parameter	Type	Description
image_url	string	Public URL of an image — a tight crop of one line of text. Provide either this or image_base64. Recognition is by visual shape (no OCR/text needed); Latin & Cyrillic supported.
image_base64	string	Base64-encoded image (raw base64 or a data:image/...;base64 URI), max 8 MB decoded — use this to send a local file/screenshot without hosting it. Provide either this or image_url.
top_k	integer	Number of font matches to return (3–20, default 8).

get_font

Get full metadata for one font family by slug: styles, weights, axes, license, subsets and download/CSS URLs.

read-only · idempotent

Parameter	Type	Description
slug (required)	string	Family slug, e.g. 'inter', 'playfair-display'.

get_font_files

List every font file (weight/italic/format + direct woff2/ttf URL) for a family — handy for building custom @font-face rules.

read-only · idempotent

Parameter	Type	Description
slug (required)	string	Family slug, e.g. 'inter'.

get_fonts_css

Generate ready-to-use @font-face CSS for a family spec (Google-Fonts-compatible), e.g. "inter:wght@400,700" or a variable range "inter:wght@300..900". Returns CSS text.

read-only · idempotent

Parameter	Type	Description
family (required)	string	Family spec, e.g. "inter:wght@400,700" or "inter:wght@300..900".
display	string: swap | auto | block | fallback | optional	font-display value (default swap).

get_font_download_url

Return the direct ZIP download URL for a font family (all styles + a ready fonts.css). Does NOT download — hand the URL to the user or fetch it separately.

read-only · idempotent

Parameter	Type	Description
slug (required)	string	Family slug, e.g. 'inter'.

Colors

check_contrast

Check the WCAG contrast ratio between a foreground and background color, with AA/AAA pass/fail for normal and large text.

read-only · idempotent

Parameter	Type	Description
fg (required)	string	Foreground color (hex, rgb(), or hsl()).
bg (required)	string	Background color (hex, rgb(), or hsl()).

get_color_shades

Generate tints and shades for a base color (lighter/darker steps) with hex values.

read-only · idempotent

Parameter	Type	Description
hex (required)	string	Base color in hex, rgb(), or hsl().
step	string: 5 | 10 | 20 | 25	Step percentage (default 10).
limit	integer	Cap on tints/shades (default fills to ~100%).

name_color

Get the closest human-readable name for one or more colors. Pass a single hex or several comma-separated (e.g. "#3b82f6,#000,#ff7f50"); returns each input with its nearest color name, the reference hex, an exact-match flag and the perceptual distance.

read-only · idempotent

Parameter	Type	Description
hex (required)	string	A hex color, or several comma-separated (e.g. "#3b82f6,#000,#ff7f50"). Up to 100 at once.

extract_colors

Extract a dominant-color palette from an image. Send either a public image_url or image_base64 (base64/data-URI, e.g. a local screenshot). The image is processed in memory and never stored. Each color comes back with its hex, rgb, hsl, share of the image, and the closest human color name — a named palette in one call.

read-only · idempotent · fetches external URLs

Parameter	Type	Description
image_url	string	Public URL of the image to pull the palette from. Provide either this or image_base64.
image_base64	string	Base64-encoded image (raw base64 or a data:image/...;base64 URI), max 10 MB decoded — use this to send a local file/screenshot without hosting it. Provide either this or image_url.
count	integer	How many colors to return (2–16, default 8).
mode	string	Palette mode: "balanced" (default), "vibrant", or "muted".

Palettes

search_palettes

Search the color-palette catalog by name, tone, temperature, mood, harmony, exact color count and tags. Returns a paginated list.

read-only · idempotent

Parameter	Type	Description
name	string	Fuzzy name match.
tone	string: light | dark | mixed	Overall tone.
temperature	string: warm | cool | neutral	Color temperature.
mood	string	e.g. pastel, muted, earthy, vibrant, monochrome.
harmony	string	e.g. analogous, complementary, triadic, monochromatic, split-complementary, tetradic.
color_count	integer	Exact number of colors.
tags	array	Tag slugs — ALL must match (AND).
order	string: newest | popular | name	Sort order (default newest).
per_page	integer	Results per page (default 24).
page	integer	Page number.

get_palette

Get one color palette by id: its colors (hex), name/derived title, mood, harmony, temperature and tags.

read-only · idempotent

Parameter	Type	Description
id (required)	integer	Palette id.

Code

minify_code

Minify or beautify JS, CSS, HTML, SVG, JSON or XML text. Set type=auto to sniff the language. The code is only parsed and re-printed — never executed and never stored.

read-only · idempotent

Parameter	Type	Description
code (required)	string	Source code to transform.
type (required)	string: js | css | html | svg | json | xml | auto	Source language, or 'auto' to sniff.
mode	string: minify | beautify	Default minify.
keep_license	boolean	Preserve /*! ... */ license comments when minifying.

detect_code

Detect the language/format of a code snippet. Static analysis only — the snippet is never executed and never stored.

read-only · idempotent

Parameter	Type	Description
code (required)	string	Snippet to inspect. Max 200,000 chars.

convert_code

Convert code between text formats (e.g. JSON↔YAML, CSS↔SCSS). Pure text transformation: the source is parsed and re-serialized, never executed and never stored. Use list_code_converters for valid from/to ids and per-converter options.

read-only · idempotent

Parameter	Type	Description
code (required)	string	Source code to convert.
from (required)	string	Source format id (see list_code_converters).
to (required)	string	Target format id.
options	object	Per-converter options (see optionsSchema in list_code_converters).

list_code_converters

List available code converters with their from/to ids and per-converter option schemas.

read-only · idempotent

No parameters.

SVG

optimize_svg

Optimize/clean SVG markup (SVGO). Pure markup transformation — nothing is executed or stored. Returns minified SVG plus before/after sizes.

read-only · idempotent

Parameter	Type	Description
svg (required)	string	SVG source. Max 500,000 chars.
preset	string: safe | balanced | aggressive	Optimization preset (default balanced).

svg_to_datauri

Encode an SVG (or fetched image) as a CSS-ready data: URI. Provide either raw svg or a url.

read-only · idempotent · fetches external URLs

Parameter	Type	Description
svg	string	Raw SVG markup. Mutually exclusive with url.
url	string	Public image URL the server will fetch.
encoding	string: utf8 | base64	Defaults: utf8 for SVG, base64 for raster.
quotes	string: single | double	Quote style for the data URI (default double).

list_svg_presets

List the available SVG optimization presets and what each one does.

read-only · idempotent

No parameters.

Dev

list_scss_mixins

List the SCSS mixin catalog (id, title, short description), optionally filtered by group or search.

read-only · idempotent

Parameter	Type	Description
group	string	e.g. Bootstrap, Project, Pattern, Placeholder.
search	string	Fuzzy substring across id/title/short/desc.
fields	string: summary | full	Detail level (default summary).

get_scss_mixin

Get one SCSS mixin by id: full source, parameters and usage example.

read-only · idempotent

Parameter	Type	Description
id (required)	string	Mixin id (kebab-case), e.g. 'centerer', 'media-breakpoint-up'.

generate_clamp

Calculate a fluid CSS clamp() expression for responsive sizing between two viewport widths. Pure calculation — returns a CSS snippet, writes and stores nothing.

read-only · idempotent

Parameter	Type	Description
min_fs (required)	number	Minimum size in px.
max_fs (required)	number	Maximum size in px.
min_vw	number	Viewport width at min_fs (default 320).
max_vw	number	Viewport width at max_fs (default 1440).
unit	string: px | rem | both	Output unit (default rem).
root	number	Root font-size in px for rem conversion (default 16).

About

Built and operated by jinero.online — free design tools for fonts, icons, colors and code. The MCP server is a thin wrapper over the same public REST API: one contract, identical behavior.

This repository holds the public documentation and examples for the server. Issues and feature requests for the tools are welcome here.