From d5af78e20c9d5056bb1451fe13e512a87193406d Mon Sep 17 00:00:00 2001
From: Steve Polito <stevepolito@hey.com>
Date: Wed, 27 Aug 2025 06:00:47 -0400
Subject: [PATCH] Artificial Intelligence: Filter sensitive information

Introduces new section for Artificial Intelligence, and demonstrates how
to filter sensitive information from messages.
---
 artificial-intelligence/README.md             |  6 +++
 .../how-to/filter_sensitive_information.md    | 44 +++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 artificial-intelligence/README.md
 create mode 100644 artificial-intelligence/how-to/filter_sensitive_information.md

diff --git a/artificial-intelligence/README.md b/artificial-intelligence/README.md
new file mode 100644
index 00000000..66fad1e0
--- /dev/null
+++ b/artificial-intelligence/README.md
@@ -0,0 +1,6 @@
+# Artificial Intelligence
+
+## Security
+
+- Filter sensitive information before sending data to an LLM or chatbot.
+  [Example](./how-to/filter_sensitive_information.md).
diff --git a/artificial-intelligence/how-to/filter_sensitive_information.md b/artificial-intelligence/how-to/filter_sensitive_information.md
new file mode 100644
index 00000000..a8640c4d
--- /dev/null
+++ b/artificial-intelligence/how-to/filter_sensitive_information.md
@@ -0,0 +1,44 @@
+# 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)
+```