diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/main/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParser.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/main/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParser.java
index 605844f7c2..50ff9f782a 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/main/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParser.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/main/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParser.java
@@ -94,14 +94,26 @@ public ChatResponse parseResponse(GenerateContentResponse response, Instant star
             if (response.usageMetadata().isPresent()) {
                 GenerateContentResponseUsageMetadata metadata = response.usageMetadata().get();
 
-                int inputTokens = metadata.promptTokenCount().orElse(0);
+                int inputTokens =
+                        metadata.promptTokenCount().orElse(0)
+                                + metadata.toolUsePromptTokenCount().orElse(0);
                 int cachedTokens = metadata.cachedContentTokenCount().orElse(0);
-                int totalOutputTokens = metadata.candidatesTokenCount().orElse(0);
                 int thinkingTokens = metadata.thoughtsTokenCount().orElse(0);
-
-                // Output tokens exclude thinking tokens (following DashScope behavior)
-                // In Gemini, candidatesTokenCount includes thinking, so we subtract it
-                int outputTokens = totalOutputTokens - thinkingTokens;
+                int outputTokens =
+                        metadata.candidatesTokenCount()
+                                .map(candidateTokens -> candidateTokens + thinkingTokens)
+                                .orElseGet(
+                                        () ->
+                                                metadata.totalTokenCount()
+                                                        .map(
+                                                                total ->
+                                                                        Math.max(
+                                                                                0,
+                                                                                total
+                                                                                        - inputTokens))
+                                                        // Without candidate or total counts,
+                                                        // thoughts are the only reported output.
+                                                        .orElse(thinkingTokens));
 
                 usage =
                         ChatUsage.builder()
diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/test/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParserTest.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/test/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParserTest.java
index 0da20af442..6d1b7c307b 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/test/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParserTest.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-gemini/src/test/java/io/agentscope/extensions/model/gemini/formatter/GeminiResponseParserTest.java
@@ -216,9 +216,9 @@ void testParseUsageMetadata() {
         GenerateContentResponseUsageMetadata usageMetadata =
                 GenerateContentResponseUsageMetadata.builder()
                         .promptTokenCount(100)
-                        .candidatesTokenCount(60) // Includes thinking
+                        .candidatesTokenCount(60)
                         .thoughtsTokenCount(10) // Thinking tokens
-                        .totalTokenCount(160)
+                        .totalTokenCount(170)
                         .build();
 
         GenerateContentResponse response =
@@ -238,13 +238,71 @@ void testParseUsageMetadata() {
         // Input tokens = promptTokenCount
         assertEquals(100, usage.getInputTokens());
 
-        // Output tokens = candidatesTokenCount - thoughtsTokenCount
-        assertEquals(50, usage.getOutputTokens());
+        // Output tokens include candidate and model-generated thinking tokens.
+        assertEquals(70, usage.getOutputTokens());
 
         // Time should be > 0
         assertTrue(usage.getTime() >= 0);
     }
 
+    @Test
+    void testParseUsageMetadataClassifiesToolUseTokensAsInput() {
+        GenerateContentResponseUsageMetadata usageMetadata =
+                GenerateContentResponseUsageMetadata.builder()
+                        .promptTokenCount(500)
+                        .candidatesTokenCount(120)
+                        .toolUsePromptTokenCount(300)
+                        .thoughtsTokenCount(10)
+                        .totalTokenCount(930)
+                        .build();
+
+        GenerateContentResponse response =
+                GenerateContentResponse.builder().usageMetadata(usageMetadata).build();
+
+        ChatUsage usage = parser.parseResponse(response, startTime).getUsage();
+
+        assertNotNull(usage);
+        assertEquals(800, usage.getInputTokens());
+        assertEquals(130, usage.getOutputTokens());
+    }
+
+    @Test
+    void testParseUsageMetadataUsesTotalWhenCandidateCountIsMissing() {
+        GenerateContentResponseUsageMetadata usageMetadata =
+                GenerateContentResponseUsageMetadata.builder()
+                        .promptTokenCount(500)
+                        .toolUsePromptTokenCount(300)
+                        .totalTokenCount(930)
+                        .build();
+
+        GenerateContentResponse response =
+                GenerateContentResponse.builder().usageMetadata(usageMetadata).build();
+
+        ChatUsage usage = parser.parseResponse(response, startTime).getUsage();
+
+        assertNotNull(usage);
+        assertEquals(800, usage.getInputTokens());
+        assertEquals(130, usage.getOutputTokens());
+    }
+
+    @Test
+    void testParseUsageMetadataUsesThinkingWhenCandidateAndTotalCountsAreMissing() {
+        GenerateContentResponseUsageMetadata usageMetadata =
+                GenerateContentResponseUsageMetadata.builder()
+                        .promptTokenCount(500)
+                        .thoughtsTokenCount(10)
+                        .build();
+
+        GenerateContentResponse response =
+                GenerateContentResponse.builder().usageMetadata(usageMetadata).build();
+
+        ChatUsage usage = parser.parseResponse(response, startTime).getUsage();
+
+        assertNotNull(usage);
+        assertEquals(500, usage.getInputTokens());
+        assertEquals(10, usage.getOutputTokens());
+    }
+
     @Test
     void testParseUsageMetadataReadsCachedContentTokenCount() {
         // Gemini 报告的 cachedContentTokenCount 必须透传到 ChatUsage.cachedTokens,