Populate runs.model from the name of the assistant's language_model

app/models/run.rb

@@ -7,6 +7,13 @@ class Run < ApplicationRecord
 
   enum status: %w[queued in_progress requires_action cancelling cancelled failed completed expired].index_by(&:to_sym)
 
-  validates :status, :expired_at, :instructions, presence: true
+  before_validation :set_model, on: :create
+  validates :status, :expired_at, :model, :instructions, presence: true
   validates :tools, :file_ids, presence: true, allow_blank: true
+
+  private
+
+  def set_model
+    self.model = assistant&.language_model&.name
+  end
 end

test/models/run_test.rb

@@ -29,6 +29,17 @@ class RunTest < ActiveSupport::TestCase
     end
   end
 
+  test "model populated from assistant" do
+      r = Run.create!(
+        assistant: assistants(:keith_claude3),
+        conversation: conversations(:greeting),
+        instructions: "Some instructions",
+        status: "queued",
+        expired_at: 1.minute.from_now
+      )
+      assert_equal 'claude-3-opus-20240229', r.model
+  end
+
   test "associations are deleted upon destroy" do
     assert_difference "Step.count", -1 do
       runs(:hear_me_response).destroy