Mcpvet MCP Server

mcpvet

Vet MCP servers and agent skills before you install them.

In early 2026 the ClawHavoc wave put 1,184 malicious skills on a public skill marketplace from just 12 accounts: credential stealers and reverse shells dressed up as helpful agent skills, inheriting whatever permissions the agent itself had. Only a small minority of organizations audit the MCP servers they install, and almost none audit skill packs. The install click is the trust decision, and it usually happens with no evidence at all.

mcpvet is the pre-install check. Point it at a local MCP server directory, a SKILL.md skill directory, a client config tree, or an npm package name, and it returns a deterministic verdict with evidence for every finding: VETTED, REVIEW, or DO-NOT-INSTALL. The scan is static only. Scanned code is read as text and never executed, imported, or installed.

Install

npx -y @reneturcios/mcpvet --version
npm install -g @reneturcios/mcpvet
docker run -i --rm ghcr.io/cloudcorprecords/mcpvet mcp

Quick start

mcpvet vet ~/src/some-mcp-server
mcpvet vet ~/skills/some-skill --json
mcpvet vet-package @modelcontextprotocol/server-filesystem@2025.3.28
mcpvet mcp

CLI exit codes: 0 when the verdict is VETTED, 1 for REVIEW or DO-NOT-INSTALL, 2 for a usage or setup error, 141 when the reader closed the output pipe before the report was delivered.

What it checks

Verdict rules

• DO-NOT-INSTALL: at least one critical finding. Reverse shells, credential stealers, install droppers, curl pipe shell autostarts, and download-and-execute steps declared in skill documentation land here.
• REVIEW: at least one high or medium finding and no criticals. Dangerous capability combos, undeclared tools, typosquats, env harvesting configs, and unpinned autostarts land here. A partial scan also lands here at minimum: when a manifest is present but could not be parsed or read, the scan did not see the whole target, so VETTED is unreachable in that state.
• VETTED: no critical, high, or medium findings. Info and low findings (such as the autostart inventory itself) are still reported as evidence.

A verdict is a scan result, never a safety claim. VETTED means these checks found nothing at or above medium severity in the files scanned; it does not certify a server safe.

Scope floor (v0.1.2): DO-NOT-INSTALL is a claim about an installable MCP bundle. If the target is not an MCP target (kind unknown, meaning no server, config, or skill as its primary subject, or a mixed monorepo root whose critical findings all come from outside every identified MCP bundle), the verdict floors at REVIEW with an explicit "not an MCP target" note telling you to scope vetting to the server or skill directory. Findings are still reported as evidence; a critical inside an identified bundle still verdicts DO-NOT-INSTALL.

MCP

mcpvet mcp serves a stdio MCP server with two tools:

Scope and limits

• Static analysis only, by design. mcpvet never executes, imports, or installs the target, and vet_package never downloads the tarball. Behavior that only appears at runtime is out of scope; vet the extracted directory for capability and inventory checks.
• Tool inventory is pattern-based: tools registered through shapes the scanner does not recognize (dynamic registration, generated code) can be missed, which is why a declared manifest with no matching registrations is itself a finding.
• The walk caps at 2,000 files and 512 KiB per file. Anything skipped is counted and reported in the report's caps block, never silently dropped. When the skipped file is package.json or server.json, the verdict is also floored at REVIEW, because the manifest itself went unaudited.
• The vet target must be a directory. A regular file, a FIFO, a device, or a nonexistent path is a usage error and exits 2, never a verdict.
• Compiled native code is opaque to this scanner by construction. A tree shipping native artifacts (.node, .dll, .so, .dylib, or a prebuilds directory) draws a NATIVE-BINARY finding at medium and verdicts at least REVIEW; the finding reports presence only and claims nothing about what the binary does.
• The typosquat list is a bundled snapshot of well-known MCP server names, not the live registry.
• Pattern literals are indistinguishable from payloads in a static text scan: the source of a security scanner (or a test fixture corpus) contains the very shapes it detects, so vetting detector tooling flags its own pattern strings (observed on the Security Wave factory repos themselves, where every such critical was hand-verified as a pattern literal or a planted fixture). Treat verdicts on scanner source as REVIEW-grade evidence, not as a compromise claim.

Part of the Security Wave: hookcheck (persistence hooks), actionpin (Actions pinning), injectcheck (prompt injection in agent-read content), tracewatch (observability and root cause), mcpvet (pre-install vetting).

MIT.