fix(server-ai): stop exposing model_key/model_version on ModelConfig

model_key/model_version should only be visible via the tracker's
stamped event data, mirroring how variation_key/version are treated.
They now flow from the already-parsed _ldMeta fields straight into
the tracker factory instead of being attached to ModelConfig.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: atornsii

lib/server/ai/client.rb

@@ -38,14 +38,12 @@ def to_h
       # The ModelConfig class represents an AI model configuration.
       #
       class ModelConfig
-        attr_reader :name, :model_key, :model_version
+        attr_reader :name
 
-        def initialize(name:, parameters: {}, custom: {}, model_key: nil, model_version: nil)
+        def initialize(name:, parameters: {}, custom: {})
           @name = name
           @parameters = parameters
           @custom = custom
-          @model_key = model_key
-          @model_version = model_version
         end
 
         #
@@ -77,14 +75,11 @@ def custom(key)
         end
 
         def to_h
-          result = {
+          {
             name: @name,
             parameters: @parameters,
             custom: @custom,
           }
-          result[:modelKey] = @model_key if @model_key && !@model_key.empty?
-          result[:modelVersion] = @model_version unless @model_version.nil?
-          result
         end
       end
 
@@ -292,17 +287,15 @@ def _completion_config(key:, context:, default:, variables: nil)
             model = ModelConfig.new(
               name: variation[:model][:name],
               parameters: parameters,
-              custom: custom,
-              model_key: variation.dig(:_ldMeta, :modelKey),
-              model_version: tracked_model_version
+              custom: custom
             )
           end
 
           variation_key = variation.dig(:_ldMeta, :variationKey) || ''
           version = variation.dig(:_ldMeta, :version) || 1
           model_name = model&.name || ''
           provider_name = provider_config&.name || ''
-          model_key = model&.model_key
+          model_key = variation.dig(:_ldMeta, :modelKey)
 
           tracker_factory = lambda {
             LaunchDarkly::Server::AI::AIConfigTracker.new(

spec/server/ai/client_spec.rb

@@ -127,27 +127,6 @@
       expect(model.custom('name')).to be_nil
     end
 
-    it 'to_h omits modelKey and modelVersion when unset' do
-      model = described_class.new(name: 'fakeModel', parameters: { temperature: 0.5 })
-      expect(model.model_key).to be_nil
-      expect(model.model_version).to be_nil
-      result = model.to_h
-      expect(result).not_to have_key(:modelKey)
-      expect(result).not_to have_key(:modelVersion)
-    end
-
-    it 'to_h includes modelKey and modelVersion when set' do
-      model = described_class.new(name: 'fakeModel', model_key: 'my-model', model_version: 2)
-      result = model.to_h
-      expect(result[:modelKey]).to eq('my-model')
-      expect(result[:modelVersion]).to eq(2)
-    end
-
-    it 'to_h omits empty modelKey' do
-      model = described_class.new(name: 'fakeModel', model_key: '')
-      result = model.to_h
-      expect(result).not_to have_key(:modelKey)
-    end
   end
 
   describe LaunchDarkly::Server::AI::Client do
@@ -447,15 +426,6 @@
         expect(flag_data).not_to have_key(:modelKey)
       end
 
-      it 'reads modelKey and modelVersion from flag payload' do
-        context = LaunchDarkly::LDContext.create({ key: 'user-key', kind: 'user' })
-        config = ai_client.completion_config(key: 'model-config-with-key-version', context:)
-
-        expect(config.model).not_to be_nil
-        expect(config.model.model_key).to eq('my-model')
-        expect(config.model.model_version).to eq(2)
-      end
-
       it 'stamps modelKey and modelVersion on track data' do
         context = LaunchDarkly::LDContext.create({ key: 'user-key', kind: 'user' })
         config = ai_client.completion_config(key: 'model-config-with-key-version', context:)