diff --git a/agentscope-core/src/test/java/io/agentscope/core/tool/subagent/SubAgentToolTimeoutRetryIntegrationTest.java b/agentscope-core/src/test/java/io/agentscope/core/tool/subagent/SubAgentToolTimeoutRetryIntegrationTest.java
index e49c2c033..4b304776d 100644
--- a/agentscope-core/src/test/java/io/agentscope/core/tool/subagent/SubAgentToolTimeoutRetryIntegrationTest.java
+++ b/agentscope-core/src/test/java/io/agentscope/core/tool/subagent/SubAgentToolTimeoutRetryIntegrationTest.java
@@ -103,6 +103,10 @@ public Mono<ToolResultBlock> callAsync(ToolCallParam p) {
                                         () -> {
                                             try {
                                                 Thread.sleep(4_000);
+                                            } catch (InterruptedException e) {
+                                                Thread.currentThread().interrupt();
+                                            }
+                                            try {
                                                 Files.writeString(
                                                         tmpFile, "slow_tool round done\n");
                                             } catch (Exception ignored) {
diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/main/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalTool.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/main/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalTool.java
index 2097c96f9..88ba0b1d2 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/main/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalTool.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/main/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalTool.java
@@ -58,6 +58,11 @@ public class OpenAIMultiModalTool {
 
     private static final Logger log = LoggerFactory.getLogger(OpenAIMultiModalTool.class);
 
+    private static final String DEFAULT_VISION_MODEL = "gpt-4o";
+    private static final String DEFAULT_IMAGE_GEN_MODEL = "dall-e-3";
+    private static final String DEFAULT_TTS_MODEL = "tts-1";
+    private static final String DEFAULT_STT_MODEL = "whisper-1";
+
     /** OpenAI API key. */
     private final String apiKey;
 
@@ -68,7 +73,16 @@ public class OpenAIMultiModalTool {
     private final String baseUrl;
 
     /** Default vision model used when the caller does not specify one. */
-    private final String defaultModelName;
+    private final String defaultVisionModel;
+
+    /** Default image generation model used when the caller does not specify one. */
+    private final String defaultImageGenModel;
+
+    /** Default TTS model used when the caller does not specify one. */
+    private final String defaultTtsModel;
+
+    /** Default speech-to-text model used when the caller does not specify one. */
+    private final String defaultSttModel;
 
     /**
      * Create a new OpenAIMultiModalTool with default base URL.
@@ -94,19 +108,38 @@ public OpenAIMultiModalTool(String apiKey, String baseUrl) {
      *
      * @param apiKey the OpenAI API key
      * @param baseUrl the base URL (null for default https://api.openai.com)
-     * @param defaultModelName the default vision model name used when the caller omits the model
+     * @param defaultVisionModel the default vision model name used when the caller omits the model
      *     parameter (e.g., "gpt-4o" for OpenAI, or your backend's vision model name)
      */
-    public OpenAIMultiModalTool(String apiKey, String baseUrl, String defaultModelName) {
+    public OpenAIMultiModalTool(String apiKey, String baseUrl, String defaultVisionModel) {
+        this(
+                apiKey,
+                baseUrl,
+                defaultVisionModel,
+                DEFAULT_IMAGE_GEN_MODEL,
+                DEFAULT_TTS_MODEL,
+                DEFAULT_STT_MODEL);
+    }
+
+    private OpenAIMultiModalTool(
+            String apiKey,
+            String baseUrl,
+            String defaultVisionModel,
+            String defaultImageGenModel,
+            String defaultTtsModel,
+            String defaultSttModel) {
         if (apiKey == null || apiKey.trim().isEmpty()) {
             throw new IllegalArgumentException("OpenAI API key cannot be empty.");
         }
-        if (defaultModelName == null || defaultModelName.trim().isEmpty()) {
-            throw new IllegalArgumentException("defaultModelName cannot be empty.");
+        if (defaultVisionModel == null || defaultVisionModel.trim().isEmpty()) {
+            throw new IllegalArgumentException("defaultVisionModel cannot be empty.");
         }
         this.apiKey = apiKey;
         this.baseUrl = baseUrl;
-        this.defaultModelName = defaultModelName;
+        this.defaultVisionModel = defaultVisionModel;
+        this.defaultImageGenModel = defaultImageGenModel;
+        this.defaultTtsModel = defaultTtsModel;
+        this.defaultSttModel = defaultSttModel;
         this.client = new OpenAIClient();
     }
 
@@ -123,18 +156,138 @@ protected OpenAIMultiModalTool(OpenAIClient client) {
      * Create a new OpenAIMultiModalTool with custom client and default model (for testing).
      *
      * @param client the OpenAI client
-     * @param defaultModelName the default vision model name
+     * @param defaultVisionModel the default vision model name
      */
-    protected OpenAIMultiModalTool(OpenAIClient client, String defaultModelName) {
-        if (defaultModelName == null || defaultModelName.trim().isEmpty()) {
-            throw new IllegalArgumentException("defaultModelName cannot be empty.");
+    protected OpenAIMultiModalTool(OpenAIClient client, String defaultVisionModel) {
+        if (defaultVisionModel == null || defaultVisionModel.trim().isEmpty()) {
+            throw new IllegalArgumentException("defaultVisionModel cannot be empty.");
         }
         this.apiKey = "test-key";
         this.baseUrl = null;
-        this.defaultModelName = defaultModelName;
+        this.defaultVisionModel = defaultVisionModel;
+        this.defaultImageGenModel = DEFAULT_IMAGE_GEN_MODEL;
+        this.defaultTtsModel = DEFAULT_TTS_MODEL;
+        this.defaultSttModel = DEFAULT_STT_MODEL;
         this.client = client;
     }
 
+    /**
+     * Creates a new builder for OpenAIMultiModalTool.
+     *
+     * @return a new Builder instance
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Builder for OpenAIMultiModalTool.
+     *
+     * <p>Each capability has an independent default model. When not set via builder,
+     * the existing hardcoded default is used — no change to current behavior.
+     */
+    public static class Builder {
+        private String apiKey;
+        private String baseUrl;
+        private String defaultVisionModel;
+        private String defaultImageGenModel;
+        private String defaultTtsModel;
+        private String defaultSttModel;
+
+        /**
+         * Sets the API key for OpenAI authentication.
+         *
+         * @param apiKey the API key
+         * @return this builder instance
+         */
+        public Builder apiKey(String apiKey) {
+            this.apiKey = apiKey;
+            return this;
+        }
+
+        /**
+         * Sets a custom base URL for OpenAI API.
+         *
+         * @param baseUrl the base URL (null for default)
+         * @return this builder instance
+         */
+        public Builder baseUrl(String baseUrl) {
+            this.baseUrl = baseUrl;
+            return this;
+        }
+
+        /**
+         * Sets the default vision model for image-to-text.
+         *
+         * <p>When not set, falls back to {@code "gpt-4o"}.
+         *
+         * @param defaultVisionModel the vision model name
+         * @return this builder instance
+         */
+        public Builder defaultVisionModel(String defaultVisionModel) {
+            this.defaultVisionModel = defaultVisionModel;
+            return this;
+        }
+
+        /**
+         * Sets the default model for text-to-image generation.
+         *
+         * <p>When not set, falls back to {@code "dall-e-3"}.
+         *
+         * @param defaultImageGenModel the image generation model name
+         * @return this builder instance
+         */
+        public Builder defaultImageGenModel(String defaultImageGenModel) {
+            this.defaultImageGenModel = defaultImageGenModel;
+            return this;
+        }
+
+        /**
+         * Sets the default TTS model for text-to-audio.
+         *
+         * <p>When not set, falls back to {@code "tts-1"}.
+         *
+         * @param defaultTtsModel the TTS model name
+         * @return this builder instance
+         */
+        public Builder defaultTtsModel(String defaultTtsModel) {
+            this.defaultTtsModel = defaultTtsModel;
+            return this;
+        }
+
+        /**
+         * Sets the default speech-to-text model for audio-to-text.
+         *
+         * <p>When not set, falls back to {@code "whisper-1"}.
+         *
+         * @param defaultSttModel the STT model name
+         * @return this builder instance
+         */
+        public Builder defaultSttModel(String defaultSttModel) {
+            this.defaultSttModel = defaultSttModel;
+            return this;
+        }
+
+        /**
+         * Builds the OpenAIMultiModalTool instance.
+         *
+         * @return configured OpenAIMultiModalTool instance
+         * @throws IllegalArgumentException if apiKey is not set
+         */
+        public OpenAIMultiModalTool build() {
+            if (apiKey == null || apiKey.trim().isEmpty()) {
+                throw new IllegalArgumentException("apiKey must be set");
+            }
+            return new OpenAIMultiModalTool(
+                    apiKey,
+                    baseUrl,
+                    defaultVisionModel != null ? defaultVisionModel : DEFAULT_VISION_MODEL,
+                    defaultImageGenModel != null ? defaultImageGenModel : DEFAULT_IMAGE_GEN_MODEL,
+                    defaultTtsModel != null ? defaultTtsModel : DEFAULT_TTS_MODEL,
+                    defaultSttModel != null ? defaultSttModel : DEFAULT_STT_MODEL);
+        }
+    }
+
     /**
      * Generate image(s) based on the given prompt.
      *
@@ -186,7 +339,9 @@ public Mono<ToolResultBlock> openaiTextToImage(
                     String responseFormat) {
 
         String finalModel =
-                Optional.ofNullable(model).filter(s -> !s.trim().isEmpty()).orElse("dall-e-3");
+                Optional.ofNullable(model)
+                        .filter(s -> !s.trim().isEmpty())
+                        .orElse(this.defaultImageGenModel);
         Integer finalN = Optional.ofNullable(n).orElse(1);
         String finalSize =
                 Optional.ofNullable(size).filter(s -> !s.trim().isEmpty()).orElse("1024x1024");
@@ -318,7 +473,7 @@ public Mono<ToolResultBlock> openaiImageToText(
         String finalModel =
                 Optional.ofNullable(model)
                         .filter(s -> !s.trim().isEmpty())
-                        .orElse(this.defaultModelName);
+                        .orElse(this.defaultVisionModel);
         String finalPrompt =
                 Optional.ofNullable(prompt)
                         .filter(s -> !s.trim().isEmpty())
@@ -447,7 +602,9 @@ public Mono<ToolResultBlock> openaiTextToAudio(
                     Double speed) {
 
         String finalModel =
-                Optional.ofNullable(model).filter(s -> !s.trim().isEmpty()).orElse("tts-1");
+                Optional.ofNullable(model)
+                        .filter(s -> !s.trim().isEmpty())
+                        .orElse(this.defaultTtsModel);
         String finalVoice =
                 Optional.ofNullable(voice).filter(s -> !s.trim().isEmpty()).orElse("alloy");
         String finalResponseFormat =
@@ -541,7 +698,9 @@ public Mono<ToolResultBlock> openaiAudioToText(
                     Double temperature) {
 
         String finalModel =
-                Optional.ofNullable(model).filter(s -> !s.trim().isEmpty()).orElse("whisper-1");
+                Optional.ofNullable(model)
+                        .filter(s -> !s.trim().isEmpty())
+                        .orElse(this.defaultSttModel);
         String finalResponseFormat =
                 Optional.ofNullable(responseFormat).filter(s -> !s.trim().isEmpty()).orElse("text");
 
diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/test/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalToolTest.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/test/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalToolTest.java
index 602dd8902..779a2115c 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/test/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalToolTest.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai/src/test/java/io/agentscope/extensions/model/openai/tool/OpenAIMultiModalToolTest.java
@@ -31,6 +31,7 @@
 import io.agentscope.core.message.URLSource;
 import io.agentscope.extensions.model.openai.OpenAIClient;
 import java.util.List;
+import java.util.Map;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Mono;
@@ -81,8 +82,7 @@ void testImageToText_usesCustomDefaultModel() {
                         argThat(
                                 req -> {
                                     @SuppressWarnings("unchecked")
-                                    java.util.Map<String, Object> map =
-                                            (java.util.Map<String, Object>) req;
+                                    Map<String, Object> map = (Map<String, Object>) req;
                                     return "my-custom-vision-model".equals(map.get("model"));
                                 })))
                 .thenReturn(jsonResponse);
@@ -104,4 +104,34 @@ void testConstructor_rejectsBlankDefaultModelName() {
         assertThrows(
                 IllegalArgumentException.class, () -> new OpenAIMultiModalTool("key", null, null));
     }
+
+    @Test
+    void testBuilder_withAllCustomModels() {
+        OpenAIMultiModalTool tool =
+                OpenAIMultiModalTool.builder()
+                        .apiKey("sk-test")
+                        .baseUrl("https://custom.api.com")
+                        .defaultVisionModel("gpt-4o-mini")
+                        .defaultImageGenModel("dall-e-2")
+                        .defaultTtsModel("tts-1-hd")
+                        .defaultSttModel("whisper-1")
+                        .build();
+        assertNotNull(tool);
+    }
+
+    @Test
+    void testBuilder_usesDefaultsWhenNotSet() {
+        OpenAIMultiModalTool tool = OpenAIMultiModalTool.builder().apiKey("sk-test").build();
+        assertNotNull(tool);
+    }
+
+    @Test
+    void testBuilder_rejectsBlankApiKey() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> OpenAIMultiModalTool.builder().apiKey("").build());
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> OpenAIMultiModalTool.builder().apiKey(null).build());
+    }
 }