ensure fragments regenerated on save

app/models/ai_tool.rb

@@ -10,6 +10,7 @@ class AiTool < ActiveRecord::Base
   has_many :rag_document_fragments, dependent: :destroy, as: :target
   has_many :upload_references, as: :target, dependent: :destroy
   has_many :uploads, through: :upload_references
+  before_update :regenerate_rag_fragments
 
   def signature
     { name: name, description: description, parameters: parameters.map(&:symbolize_keys) }
@@ -31,6 +32,12 @@ class AiTool < ActiveRecord::Base
     AiPersona.persona_cache.flush!
   end
 
+  def regenerate_rag_fragments
+    if rag_chunk_tokens_changed? || rag_chunk_overlap_tokens_changed?
+      RagDocumentFragment.where(target: self).delete_all
+    end
+  end
+
   def self.preamble
     <<~JS
       /**

spec/models/ai_tool_spec.rb

@@ -268,6 +268,27 @@ RSpec.describe AiTool do
       ]
 
       expect(result).to eq(expected)
+
+      # will force a reindex
+      tool.rag_chunk_tokens = 5
+      tool.rag_chunk_overlap_tokens = 2
+      tool.save!
+
+      # this part of the API is a bit awkward, maybe we should do it
+      # automatically
+      RagDocumentFragment.update_target_uploads(tool, [upload1.id, upload2.id])
+      result = tool.runner({}, llm: nil, bot_user: nil, context: {}).invoke
+
+      expected = [
+        [{ "fragment" => "48 49 50", "metadata" => nil }],
+        [
+          { "fragment" => "48 49 50", "metadata" => nil },
+          { "fragment" => "45 46 47", "metadata" => nil },
+          { "fragment" => "42 43 44", "metadata" => nil },
+        ],
+      ]
+
+      expect(result).to eq(expected)
     end
   end
 end