Jinero MCP Server

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:

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

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

get_font

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

read-only · idempotent

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

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

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

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

get_color_shades

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

read-only · idempotent

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

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

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

get_palette

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

read-only · idempotent

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

detect_code

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

read-only · idempotent

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

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

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

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

get_scss_mixin

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

read-only · idempotent

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

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.