diff --git a/CHANGELOG.md b/CHANGELOG.md
index d78bba5..e9cb818 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,13 @@
 All notable changes to this project are documented here, following
 [Keep a Changelog](https://keepachangelog.com/) and semantic versioning.
 
+## [0.1.9] - 2026-09-12
+
+### Fixed
+
+- Reject unknown CLI flags (for example `--wriet`) with exit code 2 instead of
+  silently ignoring them and running report-only.
+
 ## [0.1.8] - 2026-09-12
 
 ### Added
diff --git a/package-lock.json b/package-lock.json
index e241c19..15863cf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "ctxtrim",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "ctxtrim",
-      "version": "0.1.8",
+      "version": "0.1.9",
       "license": "MIT",
       "bin": {
         "ctxtrim": "bin/ctxtrim.js"
diff --git a/package.json b/package.json
index b7ec74a..3f9e1ad 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ctxtrim",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "Trim what bloats your AI coding context. Scan a repo, find the high-cost/low-value files ballooning your Claude Code / Cursor / Codex context, and write ignore files to cut token cost. Zero dependencies.",
   "type": "module",
   "bin": {
diff --git a/src/cli.js b/src/cli.js
index c961521..90eb5e6 100644
--- a/src/cli.js
+++ b/src/cli.js
@@ -47,6 +47,7 @@ function parse(argv) {
     else if (has("--top")) o.top = Number(val());
     else if (has("--format")) o.format = val();
     else if (has("--fail-on-waste")) o.failOnWaste = Number(val());
+    else if (a.startsWith("-")) return { ...o, error: `ctxtrim: unknown option: ${a}\n` };
     else if (!a.startsWith("-")) {
       if (o.path !== null) return { ...o, error: "ctxtrim: only one path may be supplied\n" };
       o.path = a;
diff --git a/test/ctxtrim.test.js b/test/ctxtrim.test.js
index 08c11fc..da50d9f 100644
--- a/test/ctxtrim.test.js
+++ b/test/ctxtrim.test.js
@@ -190,6 +190,12 @@ test("CLI fails only when waste reaches the threshold", () => {
   assert.equal(pass.status, 0, `clean repo should pass a 50%% threshold\n${pass.stderr}`);
 });
 
+test("CLI rejects unknown flags", () => {
+  const result = spawnSync(process.execPath, [cli, repo, "--wriet"], { encoding: "utf8" });
+  assert.equal(result.status, 2, `--wriet should fail with exit 2\n${result.stderr}`);
+  assert.match(result.stderr, /ctxtrim: unknown (option|flag).*--wriet/i);
+});
+
 test("CLI rejects non-finite and negative numeric options", () => {
   const invalid = [
     ["--max-tokens", "abc"],