diff --git a/scripts/dev/discord-acp-plain-language-smoke.ts b/scripts/dev/discord-acp-plain-language-smoke.ts
index 5f0c4c082de5..85b2f8502f95 100644
--- a/scripts/dev/discord-acp-plain-language-smoke.ts
+++ b/scripts/dev/discord-acp-plain-language-smoke.ts
@@ -271,7 +271,7 @@ function resolveArg(flag: string, argv: string[]): string | undefined {
     return undefined;
   }
   const value = argv[idx + 1];
-  if (!value || value.startsWith("--")) {
+  if (!value || value.startsWith("-")) {
     throw new CliArgumentError(`${flag} requires a value`);
   }
   return value;
diff --git a/test/scripts/dev-tooling-safety.test.ts b/test/scripts/dev-tooling-safety.test.ts
index d22fd1fedbdd..2963546624b0 100644
--- a/test/scripts/dev-tooling-safety.test.ts
+++ b/test/scripts/dev-tooling-safety.test.ts
@@ -190,6 +190,11 @@ describe("script-specific dev tooling hardening", () => {
     expect(() => discordSmokeTesting.parseArgs(["--channel", "--json"])).toThrow(
       "--channel requires a value",
     );
+    for (const flag of ["--channel", "--token", "--timeout-ms", "--state-dir"]) {
+      expect(() => discordSmokeTesting.parseArgs([flag, "-h"])).toThrow(
+        `${flag} requires a value`,
+      );
+    }
   });
 
   it("redacts Discord webhook tokens from API paths", () => {