diff --git a/oxide-openapi-gen-ts/package-lock.json b/oxide-openapi-gen-ts/package-lock.json
index e3e9a87..9a9faa6 100644
--- a/oxide-openapi-gen-ts/package-lock.json
+++ b/oxide-openapi-gen-ts/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@oxide/openapi-gen-ts",
-  "version": "0.1.12",
+  "version": "0.1.13",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "@oxide/openapi-gen-ts",
-      "version": "0.1.12",
+      "version": "0.1.13",
       "license": "MPL-2.0",
       "dependencies": {
         "minimist": "^1.2.8",
diff --git a/oxide-openapi-gen-ts/package.json b/oxide-openapi-gen-ts/package.json
index 44ba88a..46d309a 100644
--- a/oxide-openapi-gen-ts/package.json
+++ b/oxide-openapi-gen-ts/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@oxide/openapi-gen-ts",
-  "version": "0.1.12",
+  "version": "0.1.13",
   "description": "OpenAPI client generator used to generate Oxide TypeScript SDK",
   "keywords": [
     "oxide",
diff --git a/oxide-openapi-gen-ts/src/index.ts b/oxide-openapi-gen-ts/src/index.ts
index febc66d..c9e0d47 100644
--- a/oxide-openapi-gen-ts/src/index.ts
+++ b/oxide-openapi-gen-ts/src/index.ts
@@ -15,6 +15,7 @@ import { generateMSWHandlers } from "./client/msw-handlers";
 import { generateTypeTests } from "./client/type-tests";
 import { generateZodValidators } from "./client/zodValidators";
 import { resolve } from "node:path";
+import { existsSync } from "node:fs";
 import parseArgs from "minimist";
 
 function helpAndExit(msg?: string): never {
@@ -47,10 +48,13 @@ function parseFeatures(featuresArg: string | undefined) {
       helpAndExit(`Unrecognized feature '${feature}'.`);
     }
   }
+
+  const validated = features as Feature[];
+
   return {
-    zod: features.includes("zod"),
-    msw: features.includes("msw"),
-    typetests: features.includes("typetests"),
+    zod: validated.includes("zod"),
+    msw: validated.includes("msw"),
+    typetests: validated.includes("typetests"),
   };
 }
 
@@ -58,6 +62,13 @@ async function generate(specFile: string, destDir: string, features: Features) {
   // destination directory is resolved relative to CWD
   const destDirAbs = resolve(process.cwd(), destDir);
 
+  if (!existsSync(destDirAbs)) {
+    throw new Error(`Error: destination directory does not exist.
+  Argument given: ${destDirAbs}
+  Resolved path:  ${destDirAbs}
+`);
+  }
+
   const rawSpec = await SwaggerParser.parse(specFile);
   if (!("openapi" in rawSpec) || !rawSpec.openapi.startsWith("3.0")) {
     throw new Error("Only OpenAPI 3.0 is currently supported");
diff --git a/tools/gen.sh b/tools/gen.sh
index bf5bec3..8baf909 100755
--- a/tools/gen.sh
+++ b/tools/gen.sh
@@ -19,5 +19,5 @@ SPEC_FILE="./spec.json"
 # TODO: we could get rid of this DL if a test didn't rely on it
 curl --fail "$SPEC_URL" -o $SPEC_FILE
 
-npx tsx "$ROOT_DIR/oxide-openapi-gen-ts/src/index.ts" $SPEC_FILE $DEST_DIR
-npx prettier --write --log-level error "$DEST_DIR"
+npx tsx "$ROOT_DIR/oxide-openapi-gen-ts/src/index.ts" $SPEC_FILE $DEST_DIR --features zod,msw,typetests
+npx prettier@3.2.5 --write --log-level error "$DEST_DIR"