feat(ReActAgent): add generateOptions support to ReActAgent builder (#968)

Allow users to configure LLM generation parameters via a new generateOptions() method on ReActAgent.Builder.

Author: hangweizhang

agentscope-core/src/main/java/io/agentscope/core/ReActAgent.java

@@ -138,6 +138,7 @@ public class ReActAgent extends StructuredOutputCapableAgent {
     private final int maxIters;
     private final ExecutionConfig modelExecutionConfig;
     private final ExecutionConfig toolExecutionConfig;
+    private final GenerateOptions generateOptions;
     private final PlanNotebook planNotebook;
     private final ToolExecutionContext toolExecutionContext;
     private final StatePersistence statePersistence;
@@ -159,6 +160,7 @@ private ReActAgent(Builder builder, Toolkit agentToolkit) {
         this.maxIters = builder.maxIters;
         this.modelExecutionConfig = builder.modelExecutionConfig;
         this.toolExecutionConfig = builder.toolExecutionConfig;
+        this.generateOptions = builder.generateOptions;
         this.planNotebook = builder.planNotebook;
         this.toolExecutionContext = builder.toolExecutionContext;
         this.statePersistence =
@@ -787,11 +789,17 @@ private List<ToolUseBlock> extractPendingToolCalls() {
 
     @Override
     protected GenerateOptions buildGenerateOptions() {
-        GenerateOptions.Builder builder = GenerateOptions.builder();
+        // Start with user-configured generateOptions if available
+        GenerateOptions baseOptions = generateOptions;
+
+        // If modelExecutionConfig is set, merge it into the options
         if (modelExecutionConfig != null) {
-            builder.executionConfig(modelExecutionConfig);
+            GenerateOptions execConfigOptions =
+                    GenerateOptions.builder().executionConfig(modelExecutionConfig).build();
+            baseOptions = GenerateOptions.mergeOptions(execConfigOptions, baseOptions);
         }
-        return builder.build();
+
+        return baseOptions != null ? baseOptions : GenerateOptions.builder().build();
     }
 
     // ==================== Hook Notification Methods ====================
@@ -963,6 +971,15 @@ public PlanNotebook getPlanNotebook() {
         return planNotebook;
     }
 
+    /**
+     * Gets the configured generation options for this agent.
+     *
+     * @return The generation options, or null if not configured
+     */
+    public GenerateOptions getGenerateOptions() {
+        return generateOptions;
+    }
+
     public static Builder builder() {
         return new Builder();
     }
@@ -980,6 +997,7 @@ public static class Builder {
         private int maxIters = 10;
         private ExecutionConfig modelExecutionConfig;
         private ExecutionConfig toolExecutionConfig;
+        private GenerateOptions generateOptions;
         private final Set<Hook> hooks = new LinkedHashSet<>();
         private boolean enableMetaTool = false;
         private StructuredOutputReminder structuredOutputReminder =
@@ -1157,6 +1175,39 @@ public Builder toolExecutionConfig(ExecutionConfig toolExecutionConfig) {
             return this;
         }
 
+        /**
+         * Sets the generation options for model API calls.
+         *
+         * <p>This configuration controls LLM generation parameters such as temperature, topP,
+         * maxTokens, frequencyPenalty, presencePenalty, etc. These options are passed to the
+         * model during the reasoning phase.
+         *
+         * <p><b>Example usage:</b>
+         * <pre>{@code
+         * ReActAgent agent = ReActAgent.builder()
+         *     .name("assistant")
+         *     .model(model)
+         *     .generateOptions(GenerateOptions.builder()
+         *         .temperature(0.7)
+         *         .topP(0.9)
+         *         .maxTokens(1000)
+         *         .build())
+         *     .build();
+         * }</pre>
+         *
+         * <p><b>Note:</b> If both generateOptions and modelExecutionConfig are set,
+         * the modelExecutionConfig's executionConfig will be merged into the generateOptions,
+         * with modelExecutionConfig taking precedence for execution settings.
+         *
+         * @param generateOptions The generation options for model calls, can be null
+         * @return This builder instance for method chaining
+         * @see GenerateOptions
+         */
+        public Builder generateOptions(GenerateOptions generateOptions) {
+            this.generateOptions = generateOptions;
+            return this;
+        }
+
         /**
          * Sets the structured output enforcement mode.
          *