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Stealth Amazon Comprehend

This gem provides NLP via the AWS Comprehend service. It integrates with the Stealth Controller to provide NLP against current_message.

Gem Version


To use AWS Comprehend, set the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables to your AWS account credentials. You may also want to optionally set your preferred AWS region by setting the environment variable AWS_REGION. That's the only setup required!

Using NLP

This gem adds the following methods to current_message:

  1. language identifies text written in over 100 languages and returns the dominant language in current_message with a confidence score
  2. entities returns the named entities ("People," "Places," "Locations," etc.) present in current_message
  3. key_phrases returns the key phrases or talking points and a confidence score to support for the current_message
  4. sentiment returns the overall sentiment (Positive, Negative, Neutral, or Mixed) for the current_message
  5. sentiment_score returns the scoring for each sentiment (Positive, Negative, Neutral, or Mixed) for the current_message

If current_message.message is not available, each of these will return nil.

The following examples are run on current_message.message when it is equal to "I bought a brand new Craftsman Drill at Home Depot.".


current_message.language will return an Array of dominate languages:

languages = [#<struct Aws::Comprehend::Types::DominantLanguage language_code="en", score=0.9921924471855164>]
languages.first.language_code # "en"
languages.first.score # 0.9921924471855164


current_message.entites will return an Array of entities:

entities = [#<struct Aws::Comprehend::Types::Entity score=0.5775995850563049, type="ORGANIZATION", text="Craftsman", begin_offset=21, end_offset=30>, #<struct Aws::Comprehend::Types::Entity score=0.9224900007247925, type="ORGANIZATION", text="Home Depot", begin_offset=40, end_offset=50>]
entities.first.text # "Craftsman"
entities.first.score # 5775995850563049
entities.first.type # ORGANIZATION


current_message.key_phrases will return an Array of key phrases:

key_phrases = [#<struct Aws::Comprehend::Types::KeyPhrase score=0.965133786201477, text="a brand new Craftsman Drill", begin_offset=9, end_offset=36>, #<struct Aws::Comprehend::Types::KeyPhrase score=0.9943040609359741, text="Home Depot", begin_offset=40, end_offset=50>]
key_phrases.first.text # "a brand new Craftsman Drill"
key_phrases.first.score # 0.965133786201477


current_message.sentiment will return the dominate sentiment of the message:

current_message.sentiment # "NEUTRAL"


current_message.sentiment_score will return the scoring for each sentiment of the message:

sentiment_scores = #<struct Aws::Comprehend::Types::SentimentScore positive=0.0249068271368742, negative=0.012575631029903889, neutral=0.9605817794799805, mixed=0.0019358232384547591>
sentiment_scores.positive # 0.0249068271368742
sentiment_scores.negative # 0.012575631029903889
sentiment_scores.neutral # 0.9605817794799805
sentiment_scores.mixed # 0.0019358232384547591

AWS Usage

Loading this gem into your bot doesn't automatically issue API requests to your AWS account. API requests are lazily made each time you call one of the above methods. One exception is sentiment and sentiment_score which share an API call and so that only a single API call is made between the two.


Built-in NLP for Stealth bots via AWS Comprehend






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