# mcp-stdio-shellguard

Defense-in-depth bundle for MCP stdio servers: drop-in guard for child_process.exec/spawn, AST audit CLI for unsanitized shell calls, and a reference MCP server that exposes both. Closes the Ox-Security 200k-server stdio-RCE class.

- **Type:** MCP server
- **Trust:** 60/100 (B), scored on the package rubric
- **Verification:** community-indexed — nobody has claimed this listing
- **Version:** 0.1.2
- **Author:** Matthias Meyer
- **License:** MIT
- **npm:** mcp-stdio-shellguard
- **Source:** https://github.com/studiomeyer-io/mcp-stdio-shellguard
- **Compatible clients:** claude-code, cursor, copilot, gemini (basis: transport)

## Trust

60/100 (B), scored on the package rubric
- Publisher verified: no
- Install scripts: nothing suspicious found
- Prompt-injection scan: not run
- Obfuscation scan: not run
- Evidence age: 3 days

## Security scan

- **Status:** clean
- **Scanned:** 2026-08-30T12:50:34.882Z
- **Version scanned:** 0.1.2
- **CVEs:** none found by OSV at scan time

## Tools

8 declared. Statically extracted from the shipped source — a floor on the surface, not a census.
- `guard_exec` — Defended replacement for child_process.exec. Forces an args[] vector,
- `guard_spawn` — Defended replacement for child_process.spawn. Returns stdout/stderr SHA-256 hashes
- `register_allowlist` — Register a tool name with its allowed executable + args regex patterns.
- `audit_source` — Scan a TypeScript / JavaScript path for unsanitised child_process.exec / spawn /
- `audit_report` — Format an AuditScanResult as markdown / json / sarif. Pure pass-through transformer.
- `replay_check` — Compute the canonical SHA-256 hash for an invocation and report whether the same
- `sandbox_status` — Report the active sandbox profile + concrete limits (timeout, byte caps, fd budget,
- `trust_tier` — Derive the LOW / MEDIUM / HIGH / CRITICAL trust tier for a registered tool plus

## Install

**Verdict: review** — Installable, but 1 thing to check first: No publisher has proved control of this listing; it is indexed, not vouched for.
**Cautions** (coverage gaps and advisories — never blocking)
- No publisher has proved control of this listing; it is indexed, not vouched for.
**Config** (claude-code):
```json
"{\n  \"mcpServers\": {\n    \"mcp-stdio-shellguard\": {\n      \"command\": \"npx\",\n      \"args\": [\n        \"-y\",\n        \"mcp-stdio-shellguard\"\n      ]\n    }\n  }\n}"
```

## Blast radius

Extensive to critical — no credential declaration found, from the publisher, the upstream registry, or the README. Known so far: runs commands; runs on your machine.
- Floor 45, ceiling 73 (tier: unknown)
- `unknown` means the floor and ceiling land in different bands — not measured enough to name one. It does not mean low.
- This is impact, not likelihood. A high radius is not a defect: a filesystem server is supposed to write files. It is never part of the trust score.

## Machine-readable views of this entry

- Signed JSON: https://forgeregistry.com/api/v1/packages/mcp-stdio-shellguard
- Install plan: https://forgeregistry.com/api/v1/packages/mcp-stdio-shellguard/install-plan
- Alternatives: https://forgeregistry.com/api/v1/alternatives/mcp-stdio-shellguard
- HTML page: https://forgeregistry.com/registry/mcp-stdio-shellguard
- MCP: POST https://forgeregistry.com/api/mcp → `forge_get_package` / `forge_install_plan`

## About this document

Generated by Forge (https://forgeregistry.com) — a compact rendering of the same record served, signed, at the JSON URL above. Trust and scan facts are the registry's own measurements; anything Forge did not measure is named as unmeasured rather than omitted.