Npmjs
npm registry MCP server β package intelligence, security audits, and dependency analysis for AI assistants
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@yawlabs/npmjs-mcp
Run npm registry operations from Claude Code, Cursor, and any MCP client. 63 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.
One click adds this to your mcp.hosting account so it syncs to every MCP client you use. Or install manually below.
Why this one?
Other npm MCP servers wrap npm search and call it done. This one doesn't.
- Full registry HTTP surface β 63 tools across reads, writes, orgs, teams, hooks, provenance, trusted publishers, and ops health. Not just
npm view. - Write ops that actually work in agents β
npm_deprecate,npm_dist_tag_set,npm_owner_add,npm_unpublish_versiongo directly to the HTTP API with your token. No 2FA prompts, no--otphunts, noENEEDAUTHfrom a session-bound.npmrc. - Agent-aware failure surfacing β write tools detect non-interactive context and return specific human-runnable commands (
npm login --auth-type=web) instead of looping on unrecoverable errors. - Safety by default β
npm_unpublish_*requiresconfirm: true.npm_owner_removeblocks you from locking yourself out.npm_deprecatevalidates the message format (em-dash, no trailing period) that npmjs.com's API actually accepts. - Ops playbook built in β
npm_ops_playbookreturns the canonical tool-vs-CLI-vs-CI decision matrix so your agent picks the right path on the first try. - Tool annotations β every tool declares
readOnlyHint,destructiveHint,idempotentHint, andopenWorldHint, so MCP clients can skip confirmation on safe ops. - No API key required for reads β search, packages, downloads, security, dep tree, licenses all work anonymously. Auth is opt-in via
NPM_TOKEN. - Instant startup β ships as a single bundled file with zero runtime dependencies. No 5-minute
node_modulesinstall. - Input hardening β 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"]
}
}
}
Windows:
{
"mcpServers": {
"npm": {
"command": "cmd",
"args": ["/c", "npx", "-y", "@yawlabs/npmjs-mcp"]
}
}
}
Why the extra step on Windows? Since Node 20,
child_process.spawncannot directly execute.cmdfiles (that's whatnpxis on Windows). Wrapping withcmd /cis 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"],
"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
| Environment variable | Default | Description |
|---|---|---|
NPM_TOKEN | (none) | npm access token. Required only for write/auth/org/access/hooks tools. A Granular Access Token is strongly preferred over a Classic Automation token. |
NPM_REGISTRY | https://registry.npmjs.org | Alternate registry (enterprise/private). Must support the npm HTTP API shape. |
Alternate MCP clients:
| Client | Config file |
|---|---|
| Claude Code | .mcp.json (project root) or ~/.claude.json (global) |
| Claude Desktop | ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) |
| Cursor | ~/.cursor/mcp.json |
| Windsurf | ~/.codeium/windsurf/mcp_config.json |
| VS Code | .vscode/mcp.json |
Use the same JSON block shown above in any of these.
Tools (63)
Search (1)
- npm_search β Search the npm registry with qualifiers (keywords, author, scope).
Packages (6)
- npm_package β Metadata: description, dist-tags, maintainers, license, repository.
- npm_version β Detailed metadata for a specific version.
- npm_versions β All published versions with dates.
- npm_readme β README content.
- npm_dist_tags β Dist-tags (latest, next, beta, etc).
- npm_types β TypeScript type support (built-in types or
@types/*).
Dependencies (3)
- npm_dependencies β Dependency lists (prod, dev, peer, optional).
- npm_dep_tree β Transitive dependency tree (configurable depth).
- npm_license_check β License audit of a package and its direct deps.
Downloads (4)
- npm_downloads β Total download count for a period.
- npm_downloads_range β Daily download breakdown.
- npm_downloads_bulk β Compare downloads for up to 128 packages.
- npm_version_downloads β Per-version download counts.
Security (3)
- npm_audit β Check packages for known vulnerabilities.
- npm_audit_deep β Full audit with CVSS scores, CWEs, fix recommendations.
- npm_signing_keys β Registry ECDSA signing keys.
Analysis (4)
- npm_compare β Compare 2β5 packages side-by-side.
- npm_health β Maintenance, downloads, security, deprecation summary.
- npm_maintainers β Maintainers and publish history.
- npm_release_frequency β Release cadence and gaps.
Registry (3)
- npm_registry_stats β Total npm-wide download counts.
- npm_recent_changes β Recent publishes from the CouchDB changes feed.
- npm_ops_playbook β Canonical recipes for npm operations. Call this first when unsure which tool to use.
Provenance & trust (2)
- npm_provenance β Sigstore attestations (SLSA, publish).
- npm_trusted_publishers β OIDC trust relationships with CI/CD providers.
Auth (5, requires NPM_TOKEN)
- npm_whoami β Authenticated user.
- npm_profile β Profile, email, 2FA status.
- npm_tokens β List access tokens.
- npm_verify_token β One-call capability check. Call this first when debugging write failures.
- npm_user_packages β Packages published by a user.
Access & orgs (6, requires NPM_TOKEN)
- npm_collaborators β Package collaborators and permissions.
- npm_package_access β Package access settings.
- npm_org_members β Org members and roles.
- npm_org_packages β Org packages.
- npm_org_teams β Org teams.
- npm_team_packages β Team package permissions.
Workflows (2)
- npm_check_auth β Auth health check with headless publish feasibility.
- npm_publish_preflight β Pre-publish validation checklist.
Write operations (19, requires NPM_TOKEN with write scope)
These bypass the CLI/2FA friction that makes npm deprecate and friends fail locally. All use the HTTP API with your NPM_TOKEN.
- npm_deprecate β Deprecate a package or specific versions (validates message format).
- npm_undeprecate β Clear deprecation.
- npm_unpublish_version β Unpublish a version. Requires
confirm: true. - npm_unpublish_package β Unpublish an entire package. Requires
confirm: true. - npm_dist_tag_set β Point a dist-tag at a version.
- npm_dist_tag_remove β Remove a dist-tag (refuses
latest). - npm_owner_add β Add a maintainer (resolves user via
/-/user/). - npm_owner_remove β Remove a maintainer (prevents self-lockout).
- npm_access_set β Set public/private/restricted access.
- npm_access_set_mfa β Configure 2FA requirement (none/publish/automation).
- npm_team_grant / npm_team_revoke β Grant/revoke team permissions on a package.
- npm_team_create / npm_team_delete β Create/delete a team in an org.
- npm_team_member_add / npm_team_member_remove β Manage team members.
- npm_org_member_set / npm_org_member_remove β Manage org membership and roles.
- npm_token_revoke β Revoke an access token by key.
Webhooks (5, requires NPM_TOKEN)
- npm_hook_add β Register a webhook on a package, scope, or user.
- npm_hook_list β List webhooks (optional package filter).
- npm_hook_get β Fetch a single webhook.
- npm_hook_update β Update endpoint/secret.
- npm_hook_remove β Delete a webhook.
Operation decision matrix
| Operation | Preferred path | Why |
|---|---|---|
| Read (search/view/stats) | These MCP tools, no auth | Fast, zero friction |
| Deprecate / dist-tag / owner / team / hook | npm_deprecate, npm_dist_tag_*, etc. | HTTP API, no CLI 2FA friction |
| Publish | CI tag-push workflow | Version discipline, provenance, org token |
| Unpublish | npm_unpublish_version (with confirm: true) | Safer than CLI; irreversible within 72h |
| CLI fallback (rare) | npm login --auth-type=web then npm <op> | Only if MCP returns 422 |
Call npm_ops_playbook at the start of any session to get the up-to-date matrix.
Examples
Audit a dependency
> "What vulnerabilities does lodash 4.17.20 have and what's the fix?"
β npm_audit_deep({ name: "lodash", version: "4.17.20" })
Deprecate a package
> "Deprecate @myorg/legacy-sdk with a pointer to @myorg/sdk"
β npm_deprecate({ name: "@myorg/legacy-sdk", message: "Renamed to @myorg/sdk β install that instead" })
Compare package health
> "Compare fastify vs express vs koa for maintenance health"
β npm_compare({ names: ["fastify", "express", "koa"] })
β npm_health({ name: "fastify" }) // ...etc
Rotate a dist-tag
> "Point @myorg/pkg@latest at 3.2.1"
β npm_dist_tag_set({ name: "@myorg/pkg", tag: "latest", version: "3.2.1" })
Debug a write failure
> "My deprecate keeps returning 422 β what's wrong?"
β npm_verify_token() // Confirms token scope, packages, 2FA state
β npm_ops_playbook() // Returns the canonical retry sequence
Troubleshooting
"Error: NPM_TOKEN is required"
- The tool you called needs auth. Add
NPM_TOKENto theenvblock of your MCP config and restart the client. - Prefer a Granular Access Token scoped to just the packages and orgs you want touched.
"HTTP 401 Unauthorized" or "HTTP 403 Forbidden"
- Your token lacks scope on the target package. Call
npm_verify_tokenβ it reports which packages and orgs the token can actually write. - If the package requires 2FA for writes, your token must be an automation token or come from an OIDC trusted publisher. A user token will 403.
"HTTP 422 Unprocessable" on deprecate
- Common cause: message format. Use an em-dash and no trailing period:
"Renamed to @x/y β install that instead", not"Renamed to @x/y. Install that instead." - Another: specifying a
versionsrange that doesn't match any published version. Callnpm_versionsto confirm.
Windows: MCP server doesn't start
- Use the
cmd /c npx ...pattern from the Quick start section. Node 20+ can't spawn.cmdfiles directly.
Requirements
- Node.js 18+
- (Optional) npm access token for write operations
Contributing
git clone https://github.com/YawLabs/npmjs-mcp.git
cd npmjs-mcp
npm install
npm run lint # Biome check
npm run lint:fix # Auto-fix
npm run build # tsc + esbuild bundle
npm test # node --test
See CONTRIBUTING.md for the full workflow, including release process.
License
MIT
