Artificial Intelligence: Filter sensitive information

Introduces new section for Artificial Intelligence, and demonstrates how
to filter sensitive information from messages.

Author: stevepolitodesign

artificial-intelligence/README.md

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+# Artificial Intelligence
+
+## Security
+
+- Filter sensitive information before sending data to an LLM.
+  [Example](./how-to/filter_sensitive_information.md).

artificial-intelligence/how-to/filter_sensitive_information.md

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+# Filter Sensitive Information
+
+Before sending free text to an LLM or chatbot, filter all messages for
+potentially sensitive information first.
+
+```ruby
+require "openai"
+require "top_secret"
+
+openai = OpenAI::Client.new(
+  api_key: Rails.application.credentials.openai.api_key!
+)
+
+original_messages = [
+  "Ralph lives in Boston.",
+  "You can reach them at ralph@thoughtbot.com or 877-976-2687"
+]
+
+# Filter all messages
+result = TopSecret::Text.filter_all(original_messages)
+filtered_messages = result.items.map(&:output)
+
+user_messages = filtered_messages.map { {role: "user", content: it} }
+
+# Instruct LLM how to handle filtered messages
+instructions = <<~TEXT
+  I'm going to send filtered information to you in the form of free text.
+  If you need to refer to the filtered information in a response, just reference it by the filter.
+TEXT
+
+messages = [
+  {role: "system", content: instructions},
+  *user_messages
+]
+
+chat_completion = openai.chat.completions.create(messages:, model: :"gpt-5")
+response = chat_completion.choices.last.message.content
+
+# Restore the response from the mapping
+mapping = result.mapping
+restored_response = TopSecret::FilteredText.restore(response, mapping:).output
+
+puts(restored_response)
+```