apply copilot review suggestions for PR #28

Author: Aegis-AI

Libraries/MLXLLM/LLMModelFactory.swift

@@ -574,7 +574,8 @@ public final class LLMModelFactory: ModelFactory {
 
         // Build a ModelConfiguration with loaded EOS token IDs and tool call format
         var mutableConfiguration = configuration
-        mutableConfiguration.eosTokenIds = eosTokenIds.union(configuration.eosTokenIds)
+        eosTokenIds.formUnion(configuration.eosTokenIds)
+        mutableConfiguration.eosTokenIds = eosTokenIds
         if mutableConfiguration.toolCallFormat == nil {
             mutableConfiguration.toolCallFormat = ToolCallFormat.infer(
                 from: baseConfig.modelType, configData: configData)

Libraries/MLXLMCommon/ModelConfiguration.swift

@@ -101,7 +101,12 @@ public struct ModelConfiguration: Sendable {
     /// Additional tokens to use for end of string (specified as strings, converted to IDs at runtime)
     public var extraEOSTokens: Set<String>
 
-    /// EOS token IDs loaded from config.json/generation_config.json
+    /// EOS token IDs used during generation.
+    ///
+    /// At load time this set is populated by merging:
+    /// - IDs from the model's `config.json` / `generation_config.json` (loaded at runtime)
+    /// - Any additional IDs provided by the registry / caller at registration time
+    ///   (e.g. `eosTokenIds: [0]` in ``LLMRegistry`` for Gemma-4 pad-token workaround)
     public var eosTokenIds: Set<Int> = []
 
     /// Tool call format for this model (nil = default JSON format)

Libraries/MLXVLM/VLMModelFactory.swift

@@ -361,7 +361,8 @@ public final class VLMModelFactory: ModelFactory {
         }
 
         var mutableConfiguration = configuration
-        mutableConfiguration.eosTokenIds = eosTokenIds.union(configuration.eosTokenIds)
+        eosTokenIds.formUnion(configuration.eosTokenIds)
+        mutableConfiguration.eosTokenIds = eosTokenIds
 
         // Auto-detect tool call format from model type if not explicitly set
         if mutableConfiguration.toolCallFormat == nil {