A connection to current MDN Web Docs, the Mozilla-maintained reference for web technologies and browser compatibility.

Use it to search web-platform documentation and look up browser compatibility information.

It helps developers check authoritative web documentation and determine whether browser features work across the browsers they support.

mdn — Plugin by mdn

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Claude Code

/plugin marketplace add mdn/mcp

agentmods

npx agentmods add plugins/mdn/mcp/plugin

Clone the repo

git clone --depth 1 https://github.com/mdn/mcp

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

mdn scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugin/.claude-plugin/plugin.json · 19 lines

What it actually says

{
  "$schema": "https://www.schemastore.org/claude-code-plugin-manifest.json",
  "name": "mdn",
  "version": "0.0.1",
  "description": "Search and access up-to-date MDN Web Docs including browser compatibility data.",
  "author": {
    "name": "MDN Web Docs",
    "url": "https://github.com/mdn"
  },
  "repository": "https://github.com/mdn/mcp",
  "license": "MPL-2.0",
  "mcpServers": {
    "mdn": {
      "type": "http",
      "url": "https://mcp.mdn.mozilla.net/"
    }
  }
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2d ago First seen · 19 lines scan A f581a3e1073f

Subscribe to this mod's changes

mdn is a plugin published in the GitHub repository mdn/mcp (183 stars, last pushed 8d ago), licensed MPL-2.0. Its token cost is not measured: this kind of file is read by the harness, not the model. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Browser automation Research Writing and docs

mdn

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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