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NPMScan is answering right now. Last checked moments ago. It exposes 23 tools.

Detect malicious or vulnerable npm packages: registry search, OSV.dev and GitHub advisory lookups

The linked repository no longer exists on GitHub — it was deleted or made private.

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What changed 58

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 1 September 2026. No other catalogue keeps this.

17 Sep 2 tool descriptions were rewritten batch_query_vulnerabilities, diff_dependencies
17 Sep a tool changed the parameters it asks for batch_query_vulnerabilities
9 Sep a tool description was rewritten get_latest_advisories
9 Sep a tool changed the parameters it asks for get_latest_advisories
8 Sep 5 tool descriptions were rewritten batch_query_vulnerabilities, check_maintainer_blast_radius, get_latest_advisories and 2 more
8 Sep a tool changed the parameters it asks for get_latest_advisories
6 Sep a tool changed version
5 Sep 3 tool descriptions were rewritten6 times that day check_maintainer_blast_radius, check_maintainer_changes, get_maintainer_profile
5 Sep a tool appeared get_maintainer_profile
4 Sep 3 tool descriptions were rewritten4 times that day audit_github_repository, compare_packages, simulate_dependency_upgrade
and 39 more, back to 1 September 2026

This one has been quiet for a while

Quiet is not dead — but it is worth knowing when it wakes up, or when someone else takes it over. We watch the repository and tell you either way.

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Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 0 min ago.

run in your terminal
claude mcp add npmscan --transport http https://npmscan.com/api/mcp
~/Library/Application Support/Claude/claude_desktop_config.json
{
  "mcpServers": {
    "npmscan": {
      "url": "https://npmscan.com/api/mcp"
    }
  }
}
~/.codex/config.toml
[mcp_servers.npmscan]
url = "https://npmscan.com/api/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "npmscan": {
      "url": "https://npmscan.com/api/mcp"
    }
  }
}
.vscode/mcp.json
{
  "mcpServers": {
    "npmscan": {
      "url": "https://npmscan.com/api/mcp"
    }
  }
}

Available tools 23

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

maintainer
check_maintainer_blast_radius
Given an npm username, finds every package npm's own maintainer:<username> search index currently returns for that account (registry.npmjs.org's /-/v1/search — the same reverse lookup npmjs.com's own site search uses; the public registry API has no dedicated 'list packages by maintainer' endpoint otherwise) and looks for a tight cluster of packages whose LATEST version was published within a short rolling window of each other. That's the shape of a compromised-account supply-chain attack: a stolen or phished credential doesn't get used on one package, it gets used on every package that account can publish to, usually within hours — the exact pattern behind the September 2025 chalk/debug ('qix') compromise, which hit roughly 18 packages within about 2 hours. A large total package count is NOT itself a red flag — many legitimate maintainers publish hundreds of packages over a career — only a tight publish-time cluster is scored, weighted up by how many packages it includes and by their combined weekly downloads/dependentsCount, since a burst touching a handful of near-zero-download packages is a very different event than one touching something with billions of weekly downloads. A cluster where most of the packages share one npm scope (e.g. @docusaurus/*) is dampened, since that's the shape of a project's own monorepo doing one coordinated release, not a compromised account spread across unrelated packages — this is why a large official org account (e.g. facebook/fb) publishing several of its own monorepos still lands well below what a plain sum of its cluster count would suggest. Multiple distinct clusters on one account combine with diminishing returns (the single worst cluster counts in full; each additional one contributes half the previous one's weight), not a plain sum — an account that does many independent, legitimate coordinated releases over its lifetime should not accumulate an unbounded score purely from being prolific. avatarUrl is the same Gravatar image npmjs.com's own profile page shows for this account, derived from the email already public in the registry's own maintainer records but served from our own /api/avatar/:hash proxy rather than linking gravatar.com directly (null only if no returned package still lists an email for this exact username). Each returned package's CURRENT maintainer list is cross-checked against the queried username (isCurrentMaintainer), since access is often already revoked by the time this runs. Natural follow-up to check_maintainer_changes: when that tool flags a newly added or fully turned-over maintainer on one package, call this with that maintainer's username to see whether the same account touched other packages around the same time. Known limitations: npm's search index is a text-relevance index, not a guaranteed-complete/real-time reverse index (results can lag or omit edge cases); results are capped at one page (up to 250 packages, ranked by npm's own relevance/popularity scoring, NOT by recency) so a very large footprint may be truncated (see resultsTruncated/totalPackagesFound) and a real cluster outside that page could be missed; and lastPublished reflects only each package's latest version, not its full history. npmscanUrl is this account's profile page on npmscan itself; npmProfileUrl is the account's actual page on npmjs.com, included for verification since that's the authoritative record of the account.
check_maintainer_changes
Reconstructs a package's maintainer-change history straight from the npm packument — every published version carries the maintainers-list SNAPSHOT as it stood at that publish plus who actually ran `npm publish` (`_npmUser`), so diffing consecutive snapshots in publish-time order recovers exactly who was added or removed and when, with no extra API calls. Flags: (1) a maintainer added recently who then published a release shortly afterward on a package with real prior history — the account-takeover/hostile-handoff shape behind incidents like ua-parser-js, event-stream, and the 2025 chalk/debug ('qix') compromise; (2) a full, sudden replacement of the entire maintainer list; (3) a long-standing maintainer quietly dropped from the list; (4) a maintainer-list change that happened on npm's site AFTER the latest release — not yet tied to any published version, which is the more urgent case since it means access changed hands but nothing has shipped with it yet. Also cross-checks the declared GitHub repository: whether it still resolves to the same owner/name (a transfer/rename), whether it's reachable at all, and whether the latest npm release landed long after any real push activity there — repository.ownerLogin/ownerAvatarUrl name and show the CURRENT owning account (the new one after a transfer, not the one originally declared in package.json), with ownerAvatarUrl served from our own /api/github/avatar proxy rather than linking avatars.githubusercontent.com directly, both null whenever the repo check itself didn't reach GitHub. Use get_package/check_package_provenance first for the package's general health and publish-integrity signals; use this specifically for the 'who controls this package, and did that change recently' question. If this flags a newly added or fully turned-over maintainer, follow up with check_maintainer_blast_radius on that maintainer's username — it lists every other package the same account currently touches and flags a tight publish-time cluster across them, the 'did this compromise hit just one package or a dozen' question this tool can't answer on its own.
get_maintainer_profile
Given an npm username, returns every package npm's own maintainer:<username> search index currently returns for that account (registry.npmjs.org's /-/v1/search — the public registry API has no dedicated 'list packages by maintainer' endpoint otherwise), plus precomputed aggregates: currentlyMaintainsCount (still listed as maintainer right now vs. already-revoked), totalWeeklyDownloads and totalDependents summed across every returned package, and avatarUrl — the same Gravatar image npmjs.com's own profile page shows for this account, derived from the email already public in the registry's own maintainer records but served from our own /api/avatar/:hash proxy rather than linking gravatar.com directly (null only if no returned package still lists an email for this exact username). This is a plain info lookup — it does NOT run the publish-cluster / compromised-account detection that check_maintainer_blast_radius does; use that tool instead when the goal is a security read on whether this account's recent activity looks like a takeover, not just a profile summary. Natural pairing with check_maintainer_changes: once that tool names a maintainer on a package, call this with that maintainer's username to see the rest of what they touch. npmscanUrl is this account's profile page on npmscan itself; npmProfileUrl is the account's actual page on npmjs.com, included for verification since that's the authoritative record of the account.
package
check_package_provenance
Checks whether a package version was published with npm's own Sigstore-backed publish provenance (`npm publish --provenance`), and cross-checks that provenance against reality rather than just reporting its presence. Three checks: (1) parses the SLSA build attestation (declared source repo, commit, builder identity, GitHub Actions run URL) and flags a builder that isn't GitHub-hosted, or an attested source repo that doesn't match package.json's own `repository` field; (2) when this version LACKS provenance, checks whether most peer packages (same npm scope, or same maintainer for an unscoped name) DO have it — a package that's the odd one out in an org that otherwise always publishes from CI is a real anomaly, not proof of malice; (3) fetches package.json from the source repository at the exact attested commit (or a best-effort matching git tag when no provenance/commit is available) and diffs its install-lifecycle scripts (preinstall/install/postinstall/prepare) and dependency names against what's actually in the published tarball — this is the single highest-signal check here, since a script or dependency that exists on npm but was never committed is exactly the pattern of a stolen-npm-token publish that bypasses CI (the event-stream/ua-parser-js incident shape). This is a heuristic, structural check: it does NOT cryptographically re-verify the Sigstore bundle (Fulcio cert chain, Rekor inclusion proof) — it trusts that npm's registry already refused to accept a publish that failed that verification, and checks the CONTENT of what the registry reports instead. Most packages don't use --provenance yet, so its bare absence is never scored on its own — only an org-norm anomaly or an actual source mismatch is. Use get_package/get_package_version first for basic package info; use this specifically to assess publish-integrity risk.
get_package
Fetch npm registry metadata for a package: latest version, install scripts (preinstall/postinstall are a key risk signal), maintainers, license, recent version history, weekly downloads, GitHub stars, TypeScript support, days since last publish, a topPackagesRank (position among npm's ~100k most-downloaded packages, from npmscan's own periodically-refreshed snapshot — not live), and a downloadTrend (growing/stable/declining vs. ~3 months ago). Also checks the LATEST version against OSV.dev for known vulnerabilities — isLatestVersionVulnerable/highestSeverity give a direct safe/not-safe answer, and each finding includes severity, a summary, and the fixedVersion to upgrade to (use get_package_version or query_vulnerabilities to check a specific older version instead). Also returns popularityTier/maintenanceTier (deterministic rule-based labels, not model-generated) and a plain-language maintenanceSummary, plus a possibleTyposquatOf flag if the name is one typo away from a top-5,000 package while itself being obscure — read `deprecated` and maintenanceSummary before recommending a package, since a long gap since the last release can mean either a stable/finished package or a slowing one. Includes a link to the full npmscan.com analysis page.
get_package_version
Fetch registry metadata for one exact version of a package (dependencies, install scripts, tarball) AND check that exact version against OSV.dev for known vulnerabilities — isVulnerable/highestSeverity give a direct answer, and each finding includes severity, a summary, and the fixedVersion to upgrade to. Use this to check a version pinned in a lockfile rather than the latest release.
analyze
analyze_install_script
Statically scans a package's preinstall/install/postinstall/prepare lifecycle scripts AND the file(s) they reference — fetched directly from the published tarball, not just the command string in package.json — against npmscan's documented red-flags rubric (/docs/red-flags): child_process use, network calls, access to sensitive paths/env (.ssh, .aws, .npmrc, *TOKEN/*KEY), obfuscation, remote binaries hosted off trusted CDNs, writes to HOME, Discord/Telegram/Pastebin exfil endpoints, eval on decoded strings, chmod+exec of downloaded binaries, and CI-metadata telemetry — plus a possibleTyposquatOf name check. Returns a weighted totalScore and riskTier ('none'/'low'/'moderate'/'high'/'critical'). This is a heuristic static scan, not proof of malice or a guarantee of safety: it doesn't execute any code, can't see behavior gated on runtime conditions, and does NOT check maintainer/ownership history (a separate red-flags signal this tool doesn't cover). Use get_package/get_package_version first for the raw script listing; use this when you need to know what an install script actually does, not just that one exists.
analyze_transitive_dependencies
Recursively resolves one or more direct/root packages' dependency graphs — e.g. the "dependencies" section of a package.json — up to maxDepth levels deep (default 2, max 3) and batch-checks every resolved package@version against OSV.dev, so vulnerabilities buried several levels down (which would never show up from checking direct dependencies alone) still surface. `summary` is a one-sentence, deterministic recap (packages scanned, unresolved count, vulnerable count and which roots pulled them in) — read it first. The `vulnerablePaths` field directly answers "which of my dependencies pulled this in" by naming the root package(s) responsible for each vulnerable transitive package; `nodes` has the full resolved graph (depth, parents, resolutionError) for deeper inspection. Scope/limits worth knowing before trusting a "clean" result: only the "dependencies" field is followed (not devDependencies/peerDependencies/optionalDependencies); each range is resolved independently per branch via semver max-satisfying against published versions — this does NOT emulate npm/yarn's actual node_modules hoisting/dedup, so read results as "which vulnerable versions are reachable in the graph," not the exact installed layout; git/file/workspace/URL/npm-alias dependencies aren't resolvable from the registry and show up with a resolutionError instead of being silently skipped; and the whole traversal is capped at a total node budget — check `truncated`/`truncationNote` rather than assuming a large graph was scanned exhaustively. Prefer batch_query_vulnerabilities instead when you only need to check exact packages you already have a flat list for (faster, no graph walk).
audit
audit_github_repository
Given a GitHub repository URL, fetches its package.json (and, if present, a pnpm-lock.yaml/package-lock.json/yarn.lock — first one found wins, in that priority order) straight from the repo's default branch and runs the same vulnerability, license-compliance, install-script, and ownership-risk pipelines batch_query_vulnerabilities/check_license_compliance/analyze_install_script/check_maintainer_changes/check_package_provenance expose individually, in one call — no copy-pasting file contents required. A monorepo (package.json#workspaces, Yarn's {packages:[...]} form, or pnpm-workspace.yaml) is detected automatically: pnpm-lock.yaml and yarn.lock already record every workspace member's dependencies directly, and for package.json-only or package-lock.json repos this additionally lists the repo's file tree, resolves the declared glob patterns to member directories, and merges each member's dependencies into the audit (capped at 50 member packages) — see isMonorepo/workspacePatterns/workspacePackageCount/workspaceNote in the result. Every direct dependency (up to 100 per call, across the root and any merged workspace members) gets: an OSV.dev vulnerability check, a license-compliance verdict against the given policy (same default as check_license_compliance: only copyleft/network-copyleft/proprietary are violations unless you pass one), and a tarball-free install-script risk signal (installScriptScanScope: 'lifecycle-scripts-only'). Up to 10 of the packages that actually declare a lifecycle script — prioritized by already-vulnerable, then possible-typosquat, then whatever's left — additionally get the full tarball-fetching deep scan analyze_install_script itself runs (installScriptScanScope: 'deep-tarball-scan', with a populated installScriptFindings array); any remaining flagged packages past that cap keep the lighter signal only, noted in deepScanNote. Any package that comes back vulnerable at high/critical severity, a possible typosquat, or deprecated (ownershipRiskEligible) additionally gets check_maintainer_changes and check_package_provenance run against it — up to 5 such packages per call (ownershipRiskChecked), prioritized the same way as the deep install-script scan, populating maintainerRiskTier/maintainerFindings and provenanceRiskTier/provenanceFindings; remaining eligible packages past that cap are named in ownershipCheckNote. This is the most expensive tool in the suite (a repo lookup, a handful of file fetches, up to 100 registry doc fetches, one OSV batch call, up to 10 tarball fetches, up to 5 packages each getting a maintainer-history check plus a provenance check — the latter alone can fan out to ~8 more registry fetches on its own — and, for a monorepo needing enumeration, one file-tree listing plus up to 50 more manifest fetches) — don't call it in a loop across many repos.
batch
batch_query_vulnerabilities
Query OSV.dev for known vulnerabilities across a whole npm dependency inventory at once: either pass a flat {packages:[...]} list, or paste raw package.json / lockfile / CycloneDX JSON / SPDX JSON content via `content`. The tool normalizes npm dependencies first, then chunk-queries OSV behind the scenes so large SBOMs don't stop at the upstream 100-package batch limit. Each finding includes severity, a summary, CVE aliases, and the fixed version — not just a bare advisory ID — so a dependency audit answer doesn't need a follow-up call per flagged package. For an explicit `packages` list or raw `package.json` content — names that were never actually resolved against a registry, unlike a real lockfile/SBOM — package names are also cross-checked against the npm registry (capped at 200 unique names): a name that doesn't exist there would otherwise show a silent, indistinguishable `vulnerabilityCount: 0` — see `unresolvedPackages`/`existenceCheckNote` and do not read those entries as a clean bill of health. A `packages[].version` that was never actually published (a typo'd or fabricated version) is cross-checked the same way — see `nonexistentVersions`. Each result also carries `signals` (deprecated, hasInstallScripts for the specific requested/resolved version, popularityTier/maintenanceTier, and possibleTyposquatOf — same deterministic rule-based labels as get_package/search_packages, capped at the same 200 unique names): a clean `vulnerabilityCount:0` does NOT mean safe to use if `signals` flags a likely typosquat, an abandoned/stale package, or a deprecation notice — surface those explicitly rather than reporting only the vulnerability count. `vulnerabilityCount`/`advisoryCount` are raw OSV/GHSA advisory counts and can over-count: OSV sometimes publishes more than one advisory record for the same underlying CVE — use `uniqueVulnerabilityCount` (deduped by shared CVE alias) when reporting 'how many distinct issues' rather than a raw advisory tally. When `content` is itself a package.json (not a lockfile/SBOM), `projectLifecycleScripts` surfaces that SCANNED PROJECT's own preinstall/install/postinstall/prepare scripts, if any — these run arbitrary code the moment someone runs `npm install` on the project itself, separate from anything a dependency does, and 'scan my package.json' should not silently skip the one script that actually executes for the project being scanned.
compare
compare_packages
Given 2-5 candidate packages for the same job (e.g. "axios vs got vs node-fetch"), fetches the same registry/popularity/maintenance/vulnerability enrichment get_package computes for each one in parallel and returns a structured side-by-side plus a deterministic, reasoned pick. Each candidate gets downloads + trend, popularityTier/maintenanceTier, GitHub stars, TypeScript support, license, deprecated status, latest-version vulnerability status, a lightweight installScriptRisk signal (scans lifecycle script command strings for known red flags — does NOT fetch the tarball; call analyze_install_script on a specific candidate for that deeper scan), and installSize (the candidate's own dist.unpackedSize plus a transitive rollup — summed dist.unpackedSize across its resolved dependency tree, walked up to depth 2 / 60 nodes per candidate; `installSize.transitive.truncated`/`sizeUnknownCount` flag when that sum is partial rather than pretending it's exact — call analyze_transitive_dependencies on a specific candidate for the full graph). `differentiators` names which candidates stand out on each dimension (most downloads, only ones with TS types, which are deprecated/vulnerable/flagged as a typosquat/install-script risk, smallest/largest install size). `recommendation.pick` is chosen deterministically from a weighted score (popularity, maintenance, deprecation, vulnerabilities, typosquat flag, install-script risk, TS support, GitHub stars — install size is reported but not scored) — never a deprecated or typosquat-flagged candidate — with `rationale` explaining why and `confidence` reflecting how close the top two scored. A name that can't be resolved (typo, unpublished, malformed) still appears in `candidates` with `found:false` and `resolutionError` set rather than failing the whole call; duplicate names in the input are rejected.
cve
get_cve
Look up authoritative NIST NVD data for one exact CVE ID (e.g. "CVE-2026-2950"), or browse/search NVD by keyword, CVSS severity, CWE, or a publication-date range. Every result is enriched with CISA KEV status (`kev`, non-null only if this CVE is a confirmed, actively-exploited-in-the-wild vulnerability — treat that as an urgent-patch signal regardless of CVSS score) and FIRST.org EPSS (`epss`, the probability of exploitation in the next 30 days — a better prioritization signal than CVSS severity alone, which measures impact, not likelihood). For a single cveId lookup, if NVD has no record yet or hasn't scored it, this falls back to the raw MITRE CVE record automatically (`source: "mitre"` on the result) rather than returning nothing. NVD is NOT npm-scoped — unlike query_vulnerabilities/get_latest_advisories, search results can include CVEs for any ecosystem, so pass keywordSearch (e.g. the package name) to narrow it. Prefer this for the authoritative CVSS score/vector/KEV/EPSS data on a CVE already found via another tool, or when a user pastes a CVE ID/link directly; prefer get_latest_advisories for npm-specific browsing. NVD enforces a strict shared rate limit, so this tool may occasionally ask you to retry in a few seconds — do so rather than assuming failure.
diff
diff_dependencies
Compares two raw snapshots of a package.json, package-lock.json (npm v1-v3), yarn.lock (classic v1 or Berry), or pnpm-lock.yaml — e.g. before/after a PR — and reports which packages were added, removed, or version-bumped. For every added or bumped package (up to 100 per call), also checks whether its resolved version carries a preinstall/install/postinstall/prepare lifecycle script that the before-version did NOT have (`installScriptIntroduced`, a headline signal — a routine-looking patch bump quietly adding a postinstall is exactly the shape of a compromised-maintainer supply-chain attack) and batch-checks it against OSV.dev, reporting `vulnerabilityDelta` (introduced/fixed/still-vulnerable/still-clean) rather than just a bare isVulnerable flag. `installScriptIntroduced` is a boolean across all four lifecycle keys, so it treats a bare `"prepare": "husky"` bump the same as a newly-added network-capable `postinstall` — read `installScriptKeysIntroduced` (null when only npm-lock's boolean hint was available, not the real scripts object; otherwise the actual key(s) added) to tell those apart before treating a flag as high-severity. Scope notes: only direct dependencies are diffed for package.json/package-lock.json/pnpm-lock.yaml (their own formats distinguish direct from transitive); yarn.lock has no such distinction, so its side of the diff covers every resolved package in the file — expect a larger added/removed count when diffing a yarn.lock, and check `comparisonNote` when the two snapshots are different formats. The install-script check is presence-only (read from the registry packument or lockfile metadata, not a tarball content scan) — use analyze_install_script for a deep-dive on anything flagged here. Ideal for a CI gate reviewing a dependency-changing PR.
enrich
enrich_npm_audit
Given the raw output of `npm audit --json` (npm 7+'s `{vulnerabilities: {...}}` format, or legacy npm 6's `{advisories: {...}}`), parses it directly — no need to re-paste package.json/lockfile content — and runs it through the same patch-now/patch-soon/scheduled/monitor ranking prioritize_remediation exposes for hand-built finding lists. npm audit's JSON almost never includes a CVE id (only a GHSA advisory URL), so this resolves each GHSA to its CVE alias via OSV.dev when one exists (ghsaResolvedToCveCount reports how many) before doing the same CISA KEV + FIRST.org EPSS + severity scoring — skipping this step would silently degrade most findings to severity-only ranking despite prioritize_remediation being built around CVE-keyed KEV/EPSS data. Also carries through npm-audit-specific context prioritize_remediation itself has no field for: isDirect (direct vs. transitive dependency) and fixAvailable/fixTarget (npm's own computed fix — note fixTarget can name a different package than the vulnerable one, e.g. bumping a parent to pull in a patched transitive dependency). A package with more than one distinct advisory in the source report only has its first advisory used for ranking; a warning names the package so query_vulnerabilities can be called on it directly for the rest. `yarn audit --json` and `pnpm audit --json` use different report shapes and are not supported — use batch_query_vulnerabilities with the project's manifest/lockfile for those instead.
generate
generate_sbom
Given the same inputs batch_query_vulnerabilities accepts — either a flat {packages:[...]} list, or raw package.json / lockfile / CycloneDX JSON / SPDX JSON content via `content` — emits a spec-valid CycloneDX 1.6 or SPDX 2.3 JSON document (pick with `format`, default 'cyclonedx') with npmscan's own OSV.dev vulnerability findings and registry license data embedded in each spec's native fields: CycloneDX gets a top-level `vulnerabilities[]` array (VEX `analysis.state: 'in_triage'` — an unreviewed automated finding, not a claim of exploitability) and per-component `licenses[]`; SPDX (which has no vulnerabilities array in 2.3) gets one `externalRefs` SECURITY/advisory entry per finding and `licenseDeclared`/`licenseConcluded`. Only a flat package inventory is known here, so the CycloneDX `dependencies[]` transitive graph and any SPDX package hierarchy are intentionally omitted rather than fabricated. Set `includeVulnerabilities`/`includeLicenses` to false to skip either enrichment pass (faster, no registry/OSV calls for that pass); pass `policy` (same shape as check_license_compliance) to also get per-package compliance context; `componentName`/`componentVersion` name the SBOM's own root component/document if known.
latest
get_latest_advisories
Browse recently published npm security advisories and known-malicious-package findings. Three disjoint sources, selected via type: "reviewed" (default) is GitHub's curated, mostly CVE-backed advisories; "malware" is GitHub's own known-malicious-package advisories; "osv" is OSV.dev's OpenSSF malicious-packages feed, which covers far more malicious npm packages than GitHub ever republishes under a GHSA id. None of "malware"/"osv" carry a CVE or meaningful CWE beyond "embedded malicious code". Filter by severity, vulnerability category (XSS, SQL/NoSQL Injection, SSRF, Access Control, Code Injection, etc. — reviewed only), an affected package name, or (reviewed/malware only) look up one exact advisory by GHSA or CVE ID. Paginated with an opaque cursor: pass a previous response's nextCursor back in as cursor to fetch the next page.
license
check_license_compliance
Given a list of packages (name + optional exact version or semver range — e.g. straight from a package.json "dependencies" object) and an optional allow/deny license policy, resolves each package's declared SPDX license and reports a compliance verdict per package. Classifies every license into one of permissive/weak-copyleft/copyleft/network-copyleft/proprietary/public-domain/unknown, and understands simple SPDX expressions: "(MIT OR GPL-3.0)" is compliant if EITHER side is permitted (a consumer may legally pick the clean alternative), "MIT AND Apache-2.0" requires both sides to pass, and "X WITH exception" is judged on X. A mixed/nested expression like "(MIT OR ISC) AND Apache-2.0" is reported as needsReview rather than guessed at. `policy.deny` entries always win over `policy.allow` (so a name can appear in both without a silent contradiction); with `policy.allow` set, anything not matching it is a violation (unproven is treated as non-compliant); with neither given, the default policy flags only copyleft/network-copyleft/proprietary (e.g. GPL/AGPL/UNLICENSED) — weak-copyleft (LGPL/MPL/EPL) and unrecognized license strings are surfaced but not auto-flagged. Policy entries accept an exact SPDX id, a family prefix ("GPL" catches GPL-2.0/GPL-3.0-only/etc.), or a category name. This reads only the registry-declared `license` field — it does not fetch or parse LICENSE file contents from the source repository.
packages
search_packages
Search the npm registry by name or keywords. Each result includes its current weekly/monthly download counts, dependentsCount (how many other npm packages depend on it), topPackagesRank (position among npmscan's own top-100k-by-downloads snapshot — not live, but a second independent popularity signal), and deterministic (not model-generated) popularityTier/maintenanceTier labels — a package matching the query with a 'very-low' popularityTier, zero dependents, or a 'stale' maintenanceTier is very likely an abandoned, copy-paste, or squatted package, not a real contender, regardless of how relevant its name/description look. A result may also carry possibleTyposquatOf — set when its name is one typo away (e.g. 'raect' vs 'react') from a top-5,000 package while itself having very low popularity; treat that as a red flag to call out explicitly, not silently filter. Use these (not name recognition or the package's own README) to judge which candidates are actually established, and call get_package on your shortlist for install-script risk, TypeScript support, and GitHub stars before recommending one. Includes a link to each package's full npmscan.com risk/analysis page.
prioritize
prioritize_remediation
Given a batch of vulnerability findings already flagged elsewhere (e.g. from batch_query_vulnerabilities, analyze_transitive_dependencies, or query_vulnerabilities across a whole package.json/lockfile audit), ranks them by what to actually fix first. Combines CISA KEV status (confirmed active exploitation in the wild — an automatic top-priority override), FIRST.org EPSS (probability of exploitation in the next 30 days — the primary ranking signal, since it measures likelihood rather than just impact), and severity (a secondary/fallback signal, most useful for a GHSA finding with no CVE alias) into one composite score and a patch-now/patch-soon/scheduled/monitor tier per finding. This does NOT re-query OSV/NVD itself — pass in the severity/CVE id findings other tools already returned; it only adds KEV/EPSS enrichment (the same data get_cve returns per-CVE) and ranks the batch. A CVE id shared by multiple findings in the same call is only looked up once.
remediation
get_remediation_playbook
Maps a finding's `rule` value from analyze_install_script, check_maintainer_changes, or check_package_provenance to the matching human-authored incident-response playbook (the same content published at /docs/playbooks) and returns its concrete, ordered steps, severity tier, real-incident references, and prevention tips — not just a link. Pass the exact `rule` string(s) a prior finding already returned (batch up to 10 in one call to cover a whole findings array; duplicates resolving to the same playbook are deduplicated) or an `id` to look up a specific playbook by slug directly. Each matched rule also gets its own short situationNote explaining specifically what that rule caught — so a batch of several different rules landing on the same playbook does not read as identical, repeated boilerplate. An unrecognized rule or id is not an error — it comes back with matched:false and a note, since a low-severity or baseline-only finding (e.g. analyze_install_script's lifecycle-present) legitimately has no dedicated playbook.
simulate
simulate_dependency_upgrade
Given a package and a current/target version, tells you whether that specific upgrade is a safe patch/minor bump or a likely-breaking major bump, before you actually run npm install. Natural follow-up to prioritize_remediation: pass its `packageName` + `currentVersion` + `fixedVersion` straight in to check whether the suggested fix is a drop-in patch or something that needs a review pass. Classifies the jump by semver (major/minor/patch/prerelease), treats a minor bump between two pre-1.0 (0.x) versions as breaking-risk per semver's own "the API isn't stable yet" convention, and flags skipping over multiple major versions in one jump (e.g. 2.x -> 5.x) as needing a per-major changelog review rather than just a diff against the final target. Beyond semver, it also checks the registry for real signals the version number alone won't tell you: whether the target version is marked deprecated, whether it introduces a preinstall/install/postinstall/prepare lifecycle script the current version didn't have, whether it tightens its engines.node requirement, and whether it is itself a prerelease. Finally it batch-checks both versions against OSV.dev and reports vulnerabilityDelta (introduced/fixed/still-vulnerable/still-clean) — catching the case where a suggested "fix" version doesn't actually clear every open CVE. Combines all of this into one riskTier (safe/low-risk/review-recommended/breaking-change-likely/unknown) with a reasons list explaining exactly which signals drove it. This does NOT read the package's changelog/release notes or scan the target tarball's source diff for actual breaking API usage — it's a fast, deterministic pre-check, not a substitute for reading the release notes on a flagged major bump. For simulating more than one upgrade at once — e.g. every "patch-now" finding prioritize_remediation just ranked — pass `packages: [{packageName, currentVersion, targetVersion?}, ...]` (1-100 items) instead of `packageName`/`currentVersion`/`targetVersion`, not both. Registry fetches are deduped/parallelized and all OSV checks for the whole batch run as one call, so this is not the same cost as N single-item calls. A package that can't be resolved at all (typo, unpublished, registry error) shows up as its own `results` entry with `fetchError` set instead of failing the whole batch.
suggest
suggest_alternative
Given a package that looks deprecated, vulnerable, abandoned, or suspicious, suggest better-maintained alternatives in the same category. This tool first checks the source package's own latest-version health (deprecation, latest-version OSV verdict, popularity/maintenance tiers, typosquat flag), then combines maintainer-provided deprecation hints with deterministic npm search-based category matching. It ranks candidates using category overlap plus search_packages-style popularity/maintenance signals, filters out typosquats and weak/stale contenders, and returns a short list with plain-language whySuggested notes. Best for turning a 'don't use this package' warning into an actionable replacement shortlist.
vulnerabilities
query_vulnerabilities
Query OSV.dev for known vulnerabilities affecting an npm package, optionally scoped to one exact version (e.g. to check whether a version pinned in a lockfile is safe). Returns isVulnerable and highestSeverity as a direct answer, plus each finding's severity, a plain-language summary, CVE aliases, and the fixedVersion to upgrade to — not a raw advisory dump. Also cross-checks the name against the npm registry: isVulnerable:false on a package that does not actually exist there (typo, unpublished, wrong ecosystem) would otherwise look identical to a genuinely clean result — a nonexistent package returns an error instead, and existenceCheckNote explains it if the registry check itself could not be completed. Use before recommending, installing, or upgrading a package.

Endpoints

URLTransportStateLatencyChecked
https://npmscan.com/api/mcp streamable-http answering 318 ms 0 min ago

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NPMScan — questions

Answers built from our own checks of this server.

What can NPMScan do?
It exposes 23 tools, read directly from the server on our last check. Among them: analyze_install_script, analyze_transitive_dependencies, audit_github_repository, batch_query_vulnerabilities, check_license_compliance, check_maintainer_blast_radius and 17 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →
What is NPMScan mostly used for?
Its tools cluster around maintainer, package and analyze. That is what this server is built to work with — the grouping comes from the actual tool names, not from a category we assigned.
Is NPMScan working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 241 ms. The bar chart above shows every period we have measured.
Is NPMScan still maintained?
The linked repository no longer exists on GitHub — it was deleted or made private. We show this because it changes what you can expect: an unmaintained server may keep answering for months and then stop without warning.
How do I connect NPMScan?
Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does NPMScan need an API key?
No. NPMScan completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 23 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is NPMScan?
It answers our handshake in 241 ms on average, which is faster than 58% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.