What to do when your chatbot is lost for words

So, you’ve built a chatbot and programmed it to answer every possible question you can imagine. But humans have a tendency to use a wide variety of language. So what should you do when the user sends your chatbot a message it just doesn’t know how to handle? We reviewed a variety of existing chatbots to help establish some good practices. We sent the bots a nonsense sentence “The light at the end of the tunnel jumps both ways.”

DO: Provide a fallback

When Siri is unable to answer a question, it falls back to searching the web. If you’re trying to build a bot which answers generic questions, consider a general fallback response.


DO: Explain the vocabulary of the app

The bot we built for the Thai Mobile Summit guides the user in what kind of questions the bot is able to answer.



DO: Provide one-tap suggestions

Many chatbot platforms allow you to add buttons to a response from the bot. The Guardian Facebook bot suggests some popular sections when it receives an unknown prompt.


DON’T: Be silent

The worst possible response for a bot is no response at all. Users quickly feel that the bot is not working. The NBA bot left us hanging…


DO: Apologize and guide the user to help resources

The Skyscanner bot both explains the problem, guiding the user towards help, and explains the input it it looking for.


DON’T just repeat yourself.

When the StubHub bot receives an unexpected response, it just keeps repeating the same question. The prompt “Great!” seems incorrect in this context.



Got any more suggestions for what to do when your bot is lost for words? Let us know in the comments.

Looking for help building your bot? Find out more about our chatbot development services at ReignDesign.



Photo credit: Questioning Robot on DeviantArt


Matt Mayer

Matt Mayer is a founder at ReignDesign. Matt is from the UK and was based in Shanghai for ten years. He is now living in Bangkok, Thailand.

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