From 9bc6429b91cacfae7baca2fbaed7673d99935e11 Mon Sep 17 00:00:00 2001
From: Rodribm10 <rodrigobm10@me.com>
Date: Sun, 19 Apr 2026 00:26:58 -0300
Subject: [PATCH] feat(captain-memory): add ContradictionCheckerService with
 LLM verification

---
 .../contradiction_checker_service.rb          | 48 +++++++++++++++
 .../contradiction_checker_service_spec.rb     | 61 +++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 enterprise/app/services/captain/contact_memories/contradiction_checker_service.rb
 create mode 100644 spec/enterprise/services/captain/contact_memories/contradiction_checker_service_spec.rb

diff --git a/enterprise/app/services/captain/contact_memories/contradiction_checker_service.rb b/enterprise/app/services/captain/contact_memories/contradiction_checker_service.rb
new file mode 100644
index 000000000..72a1f8e9c
--- /dev/null
+++ b/enterprise/app/services/captain/contact_memories/contradiction_checker_service.rb
@@ -0,0 +1,48 @@
+class Captain::ContactMemories::ContradictionCheckerService
+  MAX_CANDIDATES = 3
+  DISTANCE_THRESHOLD = 0.6
+  CHECK_MODEL = 'gpt-4o-mini'.freeze
+
+  def initialize(memory:)
+    @memory = memory
+  end
+
+  def call
+    return if @memory.embedding.blank?
+
+    candidates.each do |candidate|
+      candidate.supersede_by!(@memory) if contradicts?(candidate, @memory)
+    end
+  end
+
+  private
+
+  def candidates
+    Captain::ContactMemory
+      .active
+      .for_contact(@memory.contact_id)
+      .by_type(@memory.memory_type)
+      .where.not(id: @memory.id)
+      .where.not(embedding: nil)
+      .nearest_neighbors(:embedding, @memory.embedding, distance: 'cosine')
+      .first(MAX_CANDIDATES)
+      .select { |c| cosine_distance(c) < DISTANCE_THRESHOLD }
+  end
+
+  def cosine_distance(other)
+    other.neighbor_distance
+  end
+
+  def contradicts?(fact_a, fact_b)
+    response = RubyLLM.chat(model: CHECK_MODEL).with_temperature(0).ask(<<~PROMPT).content.to_s.downcase
+      Estes 2 fatos sobre o mesmo cliente se contradizem?
+      Fato A: "#{fact_a.content}"
+      Fato B: "#{fact_b.content}"
+      Responda apenas "sim" ou "nao".
+    PROMPT
+    response.include?('sim')
+  rescue StandardError => e
+    Rails.logger.warn("[ContradictionChecker] #{e.class}: #{e.message}")
+    false
+  end
+end
diff --git a/spec/enterprise/services/captain/contact_memories/contradiction_checker_service_spec.rb b/spec/enterprise/services/captain/contact_memories/contradiction_checker_service_spec.rb
new file mode 100644
index 000000000..f1e07eb37
--- /dev/null
+++ b/spec/enterprise/services/captain/contact_memories/contradiction_checker_service_spec.rb
@@ -0,0 +1,61 @@
+require 'rails_helper'
+
+RSpec.describe Captain::ContactMemories::ContradictionCheckerService do
+  let(:account) { create(:account) }
+  let(:contact) { create(:contact, account: account) }
+  let(:embedding_a) { Array.new(1536, 0.1) }
+  let(:embedding_b) { Array.new(1536, 0.15) }
+
+  def build_memory(attrs = {})
+    create(
+      :captain_contact_memory,
+      {
+        account: account,
+        contact: contact,
+        memory_type: 'preferencia',
+        embedding: embedding_a
+      }.merge(attrs)
+    )
+  end
+
+  describe '#call' do
+    let(:old_fact) do
+      build_memory(content: 'Prefere Stilo')
+    end
+    let(:new_fact) do
+      build_memory(content: 'Prefere Alexa agora', embedding: embedding_b)
+    end
+    let(:service) { described_class.new(memory: new_fact) }
+
+    before do
+      allow(service).to receive(:contradicts?).and_return(true)
+    end
+
+    it 'supersedes contradictory older facts of same type' do
+      old_fact
+      service.call
+      expect(old_fact.reload.superseded_by_id).to eq(new_fact.id)
+      expect(old_fact.superseded_at).not_to be_nil
+    end
+
+    it 'does not supersede non-contradictory facts' do
+      allow(service).to receive(:contradicts?).and_return(false)
+      old_fact
+      service.call
+      expect(old_fact.reload.superseded_by_id).to be_nil
+    end
+
+    it 'does not supersede across different memory types' do
+      other = build_memory(memory_type: 'reclamacao')
+      service.call
+      expect(other.reload.superseded_by_id).to be_nil
+    end
+
+    it 'no-ops when memory has no embedding' do
+      old_fact
+      embeddingless = build_memory(embedding: nil)
+      expect { described_class.new(memory: embeddingless).call }.not_to raise_error
+      expect(old_fact.reload.superseded_by_id).to be_nil
+    end
+  end
+end