pkgxray

Supply-chain security for AI agents, npm packages, and Model Context Protocol (MCP) servers.

Analyze packages before you install them. Zero-dependency Node, runs
entirely on your machine, never executes untrusted code.

Static analysis · Supply-chain intelligence · Prompt-injection detection ·
MCP security · SAFE / REVIEW / BLOCK

_{Real runs: guard clears [email protected], then blocks a sample modeled on
the 2024 @solana/web3.js compromise. ▶ 60-second walkthrough}

Quick start

npm install -g pkgxray        # or zero-install: npx pkgxray …

pkgxray guard npm:[email protected]

Decision: **SAFE**
Grade: **A+** (99/100)

No high- or medium-risk indicators were found in the provided evidence.

Notes:
- **INFO npm-vs-github-clean** — npm tarball matches the linked GitHub repo
  at the published version. (15/16 files match GitHub @4.21.0)
…

_{Real output, abridged. A BLOCK verdict instead lists every finding with
the file and evidence that produced it.}

Point it at a package, get a verdict with cited evidence — before a single
line of that package runs. guard stages the package in a sandboxed
quarantine, audits the staged copy, and only promotes it when policy allows.
It never runs npm install, lifecycle scripts, build steps, or package code.

Why pkgxray?

AI coding assistants install packages and connect to MCP servers at machine
speed, often without a human ever reading the code — and the registry they
pull from is under industrial-scale attack: roughly 455,000 malicious npm
packages were published in 2025, one every ~20 seconds by Q4
(Sonatype).
Traditional antivirus inspects what executes; pkgxray inspects what gets
installed.

npm audit and OSV-Scanner answer an essential question — does this package
have a known CVE? — and pkgxray asks it too (via OSV, before anything
downloads). But a freshly trojaned package has no CVE yet, so pkgxray also
analyzes trust: what the code actually does, whether the published npm
artifact matches the tagged GitHub source, whether the provenance attestation
is consistent with the claimed repository, and whether the docs carry a
prompt-injection payload aimed at the agent reading them.

It is intentionally conservative: verdicts come from deterministic heuristics
(no LLM in the verdict path, so injected text can't steer them), only
citable evidence is reported, and the zero-false-block calibration is
regression-gated in CI.

What it catches

_{✅ detected · ◑ partial / indirect}

Known blind spot: pkgxray reasons about bytes in the tarball. A package
that downloads its real payload after install can ship a clean tree —
pkgxray flags the capability when its shape is unambiguous, but pair it with
runtime sandboxing when that risk matters. Full analysis:
docs/threat-model.md.

Beyond detection

• Continuous monitoring — pkgxray recheck
  diffs installed deps against a stored verdict baseline and pre-vets newer versions
• MCP vetting — pkgxray mcp audits a server's tool manifest before you
  connect; --pin / --recheck catch the rug-pull; pkgxray-mcp gives any
  agent the audit tools directly
• Runtime gate — pkgxray mcp-proxy
  wraps a live MCP server on the wire: denied tools stripped, ~0.05 µs per-call
  verdict, injection scan of tool results
• Install gate — a hookshot
  hook runs guard on every package an agent tries to install, across Claude
  Code, Cursor, Windsurf, Factory Droid, and Codex (examples/hookshot/)
• Policy engine — one .pkgxray.json read by every surface; tighten
  freely, every loosening is printed; CVEs can never be allowed away; fail closed
• Opt-in behavioral canary — pkgxray canary
  runs lifecycle scripts in an OS sandbox with decoy credentials; it can
  confirm malice, never clear a package

Verdicts

Exit codes are stable and CI-friendly: 0 safe/allow · 2 block ·
3 review. The full signal-to-severity mapping is in the
severity policy.

Usage

Vet an npm package before installing

pkgxray guard npm:[email protected] [--format json]
pkgxray guard ./ext --promote-to ./approved/ext   # local dir, promote if policy allows

Vet an MCP server before connecting — full guide: docs/mcp.md

pkgxray mcp --package npm:[email protected] npx some-mcp-server
pkgxray mcp --recheck npx some-mcp-server   # catch the rug-pull

Enforce in CI/CD

pkgxray audit package-lock.json [--deep]    # also: yarn.lock, pnpm-lock.yaml, package.json
npx pkgxray recheck package-lock.json       # scheduled: exits non-zero only on a regression

A ready-made GitHub Actions workflow and the self-hostable cache server
(PKGXRAY_CACHE_URL) are in the reference.

Guard AI coding agents

{ "mcpServers": { "pkgxray": { "command": "pkgxray-mcp" } } }

Gate installs with the hookshot integration and wrap MCP
servers with pkgxray mcp-proxy.

Configuration

One optional .pkgxray.json, read by every surface. Zero config means
maximum strictness.

{
  "policy": "safe-only",              // or "allow-review" (a loosening — warns)
  "failOn": "review",                 // CI exit threshold
  "scanErrorPolicy": "fail-closed",   // a scan that errors → review, never safe

  "allow": [
    { "pkg": "[email protected]", "sha256": "e0b0…",
      "reason": "reviewed 2026-07", "expires": "2026-10-01" }
  ]
}

Precedence, mute / mcp blocks, and enforced invariants:
docs/configuration.md ·
.pkgxray.example.json

Demo

The 60-second walkthrough — the SAFE run, the blocked trojan with its exit
code, then a lockfile audit:

https://github.com/user-attachments/assets/b5a323b1-a9ec-4676-9601-1b284df81b6b

_{All captures are real runs — reproduction steps in
docs/screenshots/, which also shows the
MCP proxy, hookshot install gate, and browser extension in action.}

Comparison

Designed to run alongside npm audit and
OSV-Scanner, not replace them — they
match dependencies against known vulnerabilities; pkgxray adds the layers
they don't attempt:

_{Scoped to npm supply-chain vetting, per each tool's public docs.
OSV-Scanner covers many ecosystems beyond npm, which pkgxray does not.}

Architecture

Acquisition (OSV pre-check → fetch) → sandboxed quarantine → static analysis →
policy → verdict. The same engine backs every surface: CLI, MCP server,
runtime proxy, install hook, browser extension, and CI cache server.
Principles: never execute untrusted code · citable evidence only ·
minimize false positives · fail closed · zero runtime dependencies.

Details: docs/architecture.md ·
docs/design.md

Performance

• Local static analysis: ~25 ms — a full guard of express is ~1.3–1.5 s
  cold-cache, almost all network round-trips (Apple M1, Node 26)
• Known-vulnerable packages block at the OSV pre-check, before download
• Calibration (precision, recall, the 0-false-block gate) is measured by a
  committed benchmark corpus that fails CI when it regresses

Full numbers: docs/reference.md#performance ·
methodology: docs/benchmark.md

Documentation

Start at the documentation index. Longer-term plans:
adoption playbook and GitHub issues.

Development

npm test                 # zero-dep node --test suite
npm run benchmark        # calibration corpus: precision/recall + 0-false-block gate
npm run build:browser    # build the MV3 browser extension

Security & license

Releases are published to npm with provenance (SLSA attestation), gated on the
test suite, the calibration benchmark, and pkgxray's own supply-chain guard.
To report a vulnerability in pkgxray itself, see SECURITY.md.

MIT