Skip to main content

A few standards-related MCPs

After watching opencode/opus struggle with efficiently making sense of the broad range of IETF, W3C, WHATWG, and TC-39 specifications, I thought a set of MCP's would be helpful to make it easier.

These are all MIT licensed and offered as-is. To avoid github rate-limiting, I strongly recommend that you clone the repo and run the MCP server's in your own accounts. They are written to use Cloudflare Worker features like cache but I'm sure they could be easily adapted to run elsewhere.

WHATWG Spec MCP

Search and read WHATWG living standards -- HTML, DOM, Fetch, URL, Streams, and more.

  • list_standards -- List all WHATWG living standards, optionally filtered by search term
  • search_all_standards -- Search sections across all standards at once
  • search_standard -- Search within a specific standard by title, ID, or concept
  • search_spec_content -- Full-text search within a standard's body text
  • get_standard_toc -- Browse a standard's table of contents
  • get_standard_section -- Fetch a section's full content as markdown
  • search_issues -- Search GitHub issues and PRs across WHATWG repos

IETF Spec MCP

Search and read IETF RFCs, Internet-Drafts, and working group information.

  • search_rfcs -- Search published RFCs by title, keyword, or number
  • get_rfc / get_rfc_toc / get_rfc_section -- Fetch RFC metadata, TOC, or section content
  • search_rfc_sections / search_rfc_content -- Search within a single RFC by heading or body text
  • get_rfc_errata -- Fetch published errata for an RFC
  • search_drafts / get_draft -- Search and fetch active Internet-Drafts
  • list_working_groups / get_working_group_documents -- Browse IETF working groups and their documents
  • get_document_series -- Look up BCP, STD, or FYI document series

MDN Web Docs MCP

Search MDN, fetch page content, extract code examples, and look up browser compatibility data.

  • search_mdn / search_mdn_by_type -- Search MDN articles, optionally filtered by content type
  • get_mdn_page / get_mdn_subpages -- Fetch page content or browse child pages
  • get_browser_compat -- Look up browser compatibility for a feature
  • get_mdn_examples -- Extract just the code examples from a page
  • list_web_api_interfaces -- List all members of a Web API interface
  • get_http_header -- Fetch documentation for a specific HTTP header

Web Platform Tests (WPT) MCP

Search, browse, and check results for the shared conformance test suite used by all major browser engines.

  • search_wpt -- Search tests by name, path, or keyword with per-browser results
  • get_wpt_test / get_wpt_metadata -- Fetch test source or metadata
  • list_wpt_directory -- List test files in a WPT directory
  • get_wpt_results / get_wpt_interop_score -- Fetch pass/fail results or interop scores
  • get_wpt_diff -- Compare test results between two browser runs
  • search_wpt_by_spec -- Find tests that reference a specific spec URL

W3C Specs MCP

Search and read W3C specifications, including all CSS Working Group editor drafts.

  • search_w3c_specs / get_w3c_spec -- Search W3C specs or get metadata by shortname
  • list_css_specs -- List all CSS editor drafts from drafts.csswg.org
  • search_css_spec / get_css_section -- Search and read sections within a CSS spec

Can I Use MCP

Look up browser support data and global usage percentages.

  • search_caniuse -- Search features by keyword
  • get_caniuse_support -- Get detailed per-browser version support for a feature

Node.js API MCP

Search and read Node.js API documentation.

  • list_nodejs_modules -- List all Node.js API modules with stability indicators
  • get_nodejs_module -- Fetch a module's overview and member listing
  • search_nodejs_module -- Search within a module for methods, classes, or events
  • get_nodejs_section -- Fetch a specific section from a module's docs

TypeScript MCP

Search the TypeScript Handbook, look up tsconfig options, and read release notes.

  • search_typescript_handbook / get_typescript_handbook_page -- Search and read handbook pages
  • get_tsconfig_option / list_tsconfig_options -- Look up or list compiler options
  • get_typescript_release_notes -- Fetch release notes for a specific TypeScript version

TC39 MCP

A dedicated remote MCP server for the TC39 / ECMA-262 ecosystem. Also a stateless Cloudflare Worker.

  • search_spec / get_spec_section -- Search and read the ECMA-262 specification
  • list_proposals / get_proposal -- Browse active TC39 proposals or fetch a proposal's README and spec text
  • search_notes -- Search TC39 plenary meeting notes for discussions about a proposal or topic
  • search_test262 -- Search the test262 conformance suite for existing tests
  • get_agenda -- Fetch and parse a TC39 plenary meeting agenda
  • lookup_delegate -- Look up a TC39 delegate by name or three-letter abbreviation

TC39 Tools

Not an MCP, but worth mentioning: a collection of slash commands and skills for OpenCode and Claude Code that streamline the TC39 proposal workflow. Includes commands for creating proposals, building and reviewing spec text, generating test262 tests, preparing plenary slides, managing meeting agendas, and more. Pairs naturally with the tc39-spec-mcp server above.