@yawlabs/npmjs-mcp

One click adds this to your local Yaw MCP config so it's available in every Yaw Terminal session. Or install manually below.

Run npm registry operations from Claude Code, Cursor, and any MCP client. 64 tools covering the full registry surface: package intelligence, security audits, dependency analysis, org/team management, and the write ops that normally fight you locally (npm deprecate, npm dist-tag, npm owner, npm unpublish).

Built and maintained by Yaw Labs.

Why this one?

Other npm MCP servers wrap npm search and call it done. This one doesn't.

• Full registry HTTP surface — 64 tools across reads, writes, orgs, teams, hooks, provenance, trusted publishers, and ops health. Not just npm view.
• Write ops that actually work in agents — npm_deprecate, npm_undeprecate, npm_dist_tag_set, npm_unpublish_version go directly to the HTTP API with a Granular Access Token that has 2FA bypass. No 2FA prompts, no --otp hunts, no ENEEDAUTH from a session-bound .npmrc. (Since 2026-07-31 npm requires an interactive 2FA challenge for owner, access, team membership and grant, org membership and token changes even with 2FA bypass; for those tools the error names the exact npm command a human runs.)
• Agent-aware failure surfacing — npm_check_auth and npm_publish_preflight detect a non-interactive context and hand back a human-runnable command, and every write error names what was sent and the npm CLI equivalent, instead of looping on unrecoverable errors.
• Safety by default — npm_unpublish_* requires confirm: true. npm_owner_remove blocks you from locking yourself out. npm_deprecate rejects a message over the registry's 1024-character limit before sending it.
• Ops playbook built in — npm_ops_playbook returns the canonical tool-vs-CLI-vs-CI decision matrix so your agent picks the right path on the first try.
• Tool annotations — every tool declares readOnlyHint, destructiveHint, idempotentHint, and openWorldHint, so MCP clients can skip confirmation on safe ops.
• No API key required for reads — search, packages, downloads, security, dep tree, licenses all work anonymously. Auth is opt-in via NPM_TOKEN.
• Instant startup — ships as a single bundled file with zero runtime dependencies. No 5-minute node_modules install.
• Input hardening — package names, scopes, versions, dist-tags, and team names are all regex-validated against npm's actual constraints. Defends against CRLF and path-traversal in URL construction.

Quick start

1. Create .mcp.json in your project root

macOS / Linux / WSL:

{
  "mcpServers": {
    "npm": {
      "command": "npx",
      "args": ["-y", "@yawlabs/npmjs-mcp@latest"]
    }
  }
}

Windows:

{
  "mcpServers": {
    "npm": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "@yawlabs/npmjs-mcp@latest"]
    }
  }
}

Why the extra step on Windows? Since Node 20, child_process.spawn cannot directly execute .cmd files (that's what npx is on Windows). Wrapping with cmd /c is the standard workaround.

2. Restart and approve

Restart Claude Code (or your MCP client) and approve the npm MCP server when prompted.

3. (Optional) Add your npm token for write operations

Read-only tools work without any setup. For write tools (deprecate, dist-tag, owner, team_*, org_member_*, unpublish, hook_*, access_set*, token_revoke), add NPM_TOKEN to the env block:

{
  "mcpServers": {
    "npm": {
      "command": "npx",
      "args": ["-y", "@yawlabs/npmjs-mcp@latest"],
      "env": {
        "NPM_TOKEN": "npm_xxxxxxxxxxxx"
      }
    }
  }
}

Use a Granular Access Token scoped to just the packages and orgs you want your agent to manage.

That's it. Now ask your AI assistant:

"Deprecate my-old-pkg 1.x with a pointer to v2"

"What's the dep tree for fastify look like three levels deep?"

"Audit express for known CVEs and tell me the fix"

"Who are the maintainers of next.js and when did each one last publish?"

Configuration

Runtime

The server ships a launcher that prefers the oam runtime and falls back to Node. The server itself is a pre-bundled ESM file using only node: builtins, so both paths behave identically — verified against the full MCP surface (handshake, all 64 tools, live registry calls) on each.

oam 0.15.2, the latest release, is the minimum. The launcher asks every oam binary it can find for its version and runs the newest one at or above it, never serves on an older oam, and falls back to Node when there is none (NPMJS_MCP_RUNTIME=oam turns that into a hard error). See Configuration for the details.

Falling back costs nothing: npm has already started Node to run the launcher, so the fallback is an in-process import() — no extra spawn, no extra startup.

oam is faster, but the launcher is not. Measured on windows-arm64, n=12 medians, spawn to first MCP initialize response: