MCP Supply-Chain Lockfiles (mcp-lock.json) & GitHub SARIF Code Scanning

Pin MCP server versions, compute SHA-256 configuration digests, and enforce line-accurate SARIF v2.1.0 security gates in GitHub Actions.

1. The npx -y Supply-Chain Attack Vector (MCP04)

Most community MCP snippets instruct users to run npx -y @org/mcp-server without a version specifier. Every time the IDE restarts, npx fetches the latest published tarball from npm, exposing every developer machine to upstream package takeover or typosquatting.

2. Generating SHA-256 Lockfiles (mcpshield lock)

Use mcpshield lock to compute deterministic SHA-256 digests over each server's normalized command, pinned arguments, and environment variable keys:

node ./bin/mcpshield.mjs lock ./mcp.hardened.json --output ./mcp-lock.json

3. Line-Accurate SARIF v2.1.0 in GitHub Security

MCPShield's AST source mapper attaches exact 1-based startLine and startColumn coordinates to every SARIF result so pull-request annotations appear directly on the offending JSON property:

node ./bin/mcpshield.mjs scan ./mcp.json --sarif ./mcpshield-results.sarif.json --fail-on high