fix: reject unknown CLI options before scanning

CHANGELOG.md

@@ -3,6 +3,12 @@
 All notable changes to this project are documented here, following
 [Keep a Changelog](https://keepachangelog.com/) and semantic versioning.
 
+## [0.1.3] - 2026-09-08
+
+### Fixed
+
+- Reject unknown CLI options with an actionable error and exit code 2 instead of silently ignoring them.
+
 ## [0.1.2] - 2026-08-23
 
 ### Fixed

README.md

@@ -60,6 +60,8 @@ npx @royalpinto007/skill-audit ./my-skill --format sarif > skill-audit.sarif
 
 **Exit codes:** `0` clean (below threshold) · `1` findings at/above `--fail-on` · `2` bad usage.
 
+Unknown options are rejected with exit code `2` before scanning, so a misspelled flag cannot silently change the scan.
+
 ## In CI (GitHub Action)
 
 One line — drop it into any workflow. It gates the job and can upload findings to the Security tab:

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@royalpinto007/skill-audit",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "Security scanner for agent skills. Scan a Claude/agent Skill for prompt-injection, dangerous shell, secret access, and exfiltration before you trust it. Zero dependencies, SARIF output, npx skill-audit <path>.",
   "type": "module",
   "bin": {

src/cli.js

@@ -42,12 +42,14 @@ function parseArgs(argv) {
     else if (a.startsWith("--format=")) opts.format = a.split("=")[1];
     else if (a.startsWith("--fail-on=")) opts.failOn = a.split("=")[1];
     else if (!a.startsWith("-")) opts.path = a;
+    else return { error: `skill-audit: unknown option "${a}"\n` };
   }
   return opts;
 }
 
 export function run(argv, { version }) {
   const o = parseArgs(argv);
+  if (o.error) { process.stderr.write(o.error); return 2; }
   if (o.help) { process.stdout.write(HELP); return 0; }
   if (o.version) { process.stdout.write(version + "\n"); return 0; }
   if (o.rules) {

test/skill-audit.test.js

@@ -1,5 +1,6 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
+import { spawnSync } from "node:child_process";
 import { readFileSync } from "node:fs";
 import { fileURLToPath } from "node:url";
 import { basename, dirname, join } from "node:path";
@@ -10,6 +11,30 @@ import { RULES } from "../src/rules.js";
 const here = dirname(fileURLToPath(import.meta.url));
 const fixture = (n) => join(here, "fixtures", n);
 
+test("CLI rejects unknown options before scanning", () => {
+  const cli = join(here, "..", "bin", "skill-audit.js");
+  for (const args of [["--output", "report.json"], ["--output=report.json"], ["-x"]]) {
+    const result = spawnSync(process.execPath, [cli, fixture("clean-skill"), ...args], {
+      encoding: "utf8",
+    });
+    assert.equal(result.status, 2, `${args.join(" ")}: ${result.stderr}`);
+    assert.match(result.stderr, /unknown option/i);
+    assert.ok(result.stderr.includes(args[0]));
+    assert.equal(result.stdout, "");
+  }
+});
+
+test("CLI still accepts supported value option forms", () => {
+  const cli = join(here, "..", "bin", "skill-audit.js");
+  for (const args of [["--format", "json", "--fail-on", "info"], ["--format=json", "--fail-on=info"]]) {
+    const result = spawnSync(process.execPath, [cli, fixture("clean-skill"), ...args], {
+      encoding: "utf8",
+    });
+    assert.equal(result.status, 0, result.stderr);
+    assert.deepEqual(JSON.parse(result.stdout).findings, []);
+  }
+});
+
 test("malicious skill triggers the expected high-signal rules", () => {
   const { findings } = scanSkill(fixture("malicious-skill"));
   const ids = new Set(findings.map((f) => f.rule));