The competition between Alexa and Google Assistant is fierce. How fierce? Cover all of Las Vegas in Google Assistant ads for CES fierce? Put voice assistance in weird things like a light switch or a fridge fierce? How about “don’t dare utter our competitor’s name in your voice app” fierce?

Yep, Amazon has banned Alexa app developers from saying “Google” in their Alexa skills, it seems. [Updated with Amazon response. See below.]

One Alexa developer accidentally discovered this by submitting a voice app to Amazon with a bug.

Jo Jaquinta’s Alexa game skill Mind Maze was supposed to remind users upon exit how to relaunch the skill in the future, by saying something along the lines of: “to play again, say ‘Alexa open Mind Maze.’”

When Amazon’s review testers took a look at the skill, however, it returned the response he had built for the Google Home variation of the app instead. Whoops!

According to the reviewer, the skill had said: “If you enjoy card games, you can say ‘OK Google, talk to 21 Blackjack’…”

The skill was then promptly rejected because you can’t say “Google” in an Alexa app, you see.

Specifically, the reason Amazon provided is that an Alexa skill “should not promote Google Home.”

Wrote the reviewer:

Actual result: The skill promotes google home by saying ‘OK Google’ when user utters Stop or Cancel.

Expected result: The skill should not promote Google Home.

Of course, not sending Alexa skill users to a competing product makes sense for Amazon, and the bug certainly would have created a confusing experience for users had it gone live.

However, it’s somewhat telling that Amazon’s rejection was not because the skill was offering the incorrect exit phrase, because it would have led to user confusion, or because it violated some sort of developer guidelines. (Nowhere does the Alexa Skills developer agreement prohibit “promoting” the competition, after all.)

It was banned for reminding Alexa users about Google Home. And that’s just not allowed.

Update: Amazon says the language the Amazon reviewer used was incorrect.

“We reviewed the skill and determined that the incorrect phrase could lead to customer confusion and did not accurately portray the skill functionality. The certification representative’s response was an error,” a spokesperson said. “We do not ban the usage of brand names, although we do strive to ensure that trademarks, intellectual property, or brand names are used properly.”