@readystack/security-headers-csp-lint

Security Headers Lint - CSP and Dead Headers

Reads security headers and CSP line by line in your config file and names the lines that silently do nothing: retired headers, keywords missing their quotes, directives the browser throws away.

Install

npx @readystack/security-headers-csp-lint file

Node 18+. The same 28 rules as the VS Code extension, from a terminal or CI.

Free

• Check the open config against all 28 rules - every finding shown, nothing withheld; Check only the lines you highlight; See every rule and what each retired header or dropped directive actually does; Reopen the last report
• --rules lists every rule

With a licence ($29 once)

• Scan every config file in the workspace; Export the report as CSV, JSON or HTML; CI output that fails the build on errors; Add your own house policy rules; Re-check automatically on every save; Apply the safe fixes for you

@readystack/security-headers-csp-lint --dir ./templates --report html --out report.html

Application security consultants doing secure code review bill roughly $120 to $275 an hour, and a security-header and CSP review is a one-to-two hour job per site.

Use from an AI agent (MCP)

Claude Code · Cursor · Windsurf · any MCP client - add to your MCP config:

{ "mcpServers": { "security-headers-csp-lint": { "command": "npx", "args": ["-y", "@readystack/security-headers-csp-lint", "--mcp"] } } }

Tools: check_text and check_file (free) · check_dir (licence). The agent gets every finding with the line number.

Use in CI

- name: Security Headers Lint - CSP and Dead Headers
  run: npx -y @readystack/security-headers-csp-lint --dir . --ci

(container: docker run --rm -v "$PWD:/work" getreadystack/security-headers-csp-lint --dir /work --ci)

The folder sweep, reports and CI mode need one licence — one payment, no subscription. Set READYSTACK_LICENSE=<key> or run --license <key> once.

Get a licence