How do I connect W3c MCP Server to Claude?

Run `claude mcp add w3c-mcp -- npx -y @shuji-bonji/w3c-mcp` in Claude Code, or add the same command and arguments under mcpServers in Cursor's mcp.json or Claude Desktop's claude_desktop_config.json, then restart the client. The blocks above are ready to paste.

Is W3c MCP Server free?

The listed licence is MIT. Check the upstream terms for permitted use and commercial requirements; a public repository does not by itself mean the software is free or open source. Connected APIs and hosted services may have separate charges.

What can W3c MCP Server do?

W3c MCP Server documents 11 tools to the agent, including get_css_properties, get_html_elements, get_pwa_specs. The descriptions above come from project documentation. A live handshake does not test individual tool behavior.

W3c MCP

Unclaimed

by shuji-bonji

MCP Server for accessing W3C/WHATWG/IETF web specifications. Provides AI assistants with access to official web standards data including specifications, WebIDL definitions, CSS properties, and HTML elements.

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01 / Choose your client

02 / Before you connect

Authentication is not specified. Check the project instructions before connecting.

Install the runtime required by the project and make it available to your client.

Project instructionsEnvironment variable names (optional)

Use names from the project instructions, separated by commas. Enter names only, never secret values.

03 / Add the configuration

Source: generated from public install instructions

claude mcp add --transport stdio 'w3c-mcp' -- 'npx' '-y' '@shuji-bonji/w3c-mcp'

Run in your terminal after replacing any placeholders.

04 / Check it in your client

Open your client’s MCP settings and confirm the server connects and lists its tools. A copied configuration does not confirm a working connection.

mcpmcp-serverw3c

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Security profile

Claimed and verified servers get a weekly static scan that shows what the code can reach: external services, environment variables, shell commands, agent configuration folders, plus any dependencies with known advisories. Claim this listing to get one. How the security profile works

11 of 11 tools

Documented tools (11)

From project documentation. A server handshake does not verify each tool’s description or behavior.

get_css_properties

Get CSS property definitions from a specific spec or all specs.

get_html_elements

Get HTML element definitions from a specific spec or all specs.

get_pwa_specs

Get all Progressive Web App (PWA) related specifications.

get_w3c_spec

Get detailed information about a specific web specification.

get_webidl

Get WebIDL interface definitions for a specification. WebIDL defines the JavaScript APIs.

list_css_specs

List all CSS specifications that have property definitions available.

list_element_specs

List all specifications that have HTML element definitions available.

list_w3c_specs

List W3C/WHATWG/IETF web specifications with optional filtering.

list_webidl_specs

List all specifications that have WebIDL definitions available.

search_w3c_specs

Search web specifications by query string.

WebIDL

Tool change history

Compared across complete checks of the same configuration. Tools were listed, not invoked. Input-schema changes are not measured here.

No complete tool checks yet.

FAQ

Questions about W3c MCP Server

How do I connect W3c MCP Server to Claude?: Run `claude mcp add w3c-mcp -- npx -y @shuji-bonji/w3c-mcp` in Claude Code, or add the same command and arguments under mcpServers in Cursor's mcp.json or Claude Desktop's claude_desktop_config.json, then restart the client. The blocks above are ready to paste.
Is W3c MCP Server free?: The listed licence is MIT. Check the upstream terms for permitted use and commercial requirements; a public repository does not by itself mean the software is free or open source. Connected APIs and hosted services may have separate charges.
What can W3c MCP Server do?: W3c MCP Server documents 11 tools to the agent, including get_css_properties, get_html_elements, get_pwa_specs. The descriptions above come from project documentation. A live handshake does not test individual tool behavior.