added test to validate bug fix

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatModel.java

@@ -22,6 +22,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
 
 import io.micrometer.observation.Observation;
@@ -280,15 +281,21 @@ public Flux<ChatResponse> internalStream(Prompt prompt, ChatResponse previousCha
 			Flux<ChatCompletionResponse> response = this.anthropicApi.chatCompletionStream(request);
 
 			// @formatter:off
+			AtomicReference<String> toolCallId = new AtomicReference<>("");
 			Flux<ChatResponse> chatResponseFlux = response.switchMap(chatCompletionResponse -> {
 				AnthropicApi.Usage usage = chatCompletionResponse.usage();
 				Usage currentChatResponseUsage = usage != null ? AnthropicUsage.from(chatCompletionResponse.usage()) : new EmptyUsage();
 				Usage accumulatedUsage = UsageUtils.getCumulativeUsage(currentChatResponseUsage, previousChatResponse);
 				ChatResponse chatResponse = toChatResponse(chatCompletionResponse, accumulatedUsage);
 
 				if (!isProxyToolCalls(prompt, this.defaultOptions) && this.isToolCall(chatResponse, Set.of("tool_use"))) {
-					var toolCallConversation = handleToolCalls(prompt, chatResponse);
-					return this.internalStream(new Prompt(toolCallConversation, prompt.getOptions()), chatResponse);
+					var toolCallConversation = prompt.getInstructions();
+					if (toolCallId.get().equalsIgnoreCase(chatResponse.getMetadata().getId())) {
+						toolCallConversation = handleToolCalls(prompt, chatResponse);
+						return this.internalStream(new Prompt(toolCallConversation, prompt.getOptions()), chatResponse);
+					} else {
+						toolCallId.set(chatResponse.getMetadata().getId());
+					}
 				}
 
 				return Mono.just(chatResponse);
@@ -493,7 +500,7 @@ private List<AnthropicApi.Tool> getFunctionTools(Set<String> functionNames) {
 		}).toList();
 	}
 
-	private ChatOptions buildRequestOptions(AnthropicApi.ChatCompletionRequest request) {
+	private ChatOptions buildRequestOptions(ChatCompletionRequest request) {
 		return ChatOptions.builder()
 			.model(request.model())
 			.maxTokens(request.maxTokens())

models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/AnthropicChatModelIT.java

@@ -17,18 +17,25 @@
 package org.springframework.ai.anthropic;
 
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.stream.Collectors;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.Appender;
+import ch.qos.logback.core.AppenderBase;
+import ch.qos.logback.core.read.ListAppender;
+import org.junit.Rule;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
+import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.boot.test.system.OutputCaptureExtension;
+import org.springframework.boot.test.system.OutputCaptureRule;
 import reactor.core.publisher.Flux;
 
 import org.springframework.ai.anthropic.api.AnthropicApi;
@@ -336,10 +343,17 @@ void streamFunctionCallUsageTest() {
 
 		List<Message> messages = new ArrayList<>(List.of(userMessage));
 
+		var mockService = new MockWeatherService();
+
+		MemoryAppender appender = new MemoryAppender();
+		appender.setContext((LoggerContext) LoggerFactory.getILoggerFactory());
+		MockWeatherService.log.addAppender(appender);
+		appender.start();
+
 		var promptOptions = AnthropicChatOptions.builder()
 			.model(AnthropicApi.ChatModel.CLAUDE_3_5_SONNET.getName())
 			.functionCallbacks(List.of(FunctionCallback.builder()
-				.function("getCurrentWeather", new MockWeatherService())
+				.function("getCurrentWeather", mockService)
 				.description(
 						"Get the weather in location. Return temperature in 36°F or 36°C format. Use multi-turn if needed.")
 				.inputType(MockWeatherService.Request.class)
@@ -352,9 +366,12 @@ void streamFunctionCallUsageTest() {
 
 		logger.info("Response: {}", chatResponse);
 		Usage usage = chatResponse.getMetadata().getUsage();
+		appender.stop();
 
 		assertThat(usage).isNotNull();
+		assertThat(appender.getLoggedEvents().size()).isEqualTo(3);
 		assertThat(usage.getTotalTokens()).isLessThan(4000).isGreaterThan(1800);
+
 	}
 
 	@Test
@@ -417,4 +434,39 @@ public AnthropicChatModel openAiChatModel(AnthropicApi api) {
 
 	}
 
+	public static class MemoryAppender extends ListAppender<ILoggingEvent> {
+
+		public void reset() {
+			this.list.clear();
+		}
+
+		public boolean contains(String string, Level level) {
+			return this.list.stream()
+				.anyMatch(event -> event.toString().contains(string) && event.getLevel().equals(level));
+		}
+
+		public int countEventsForLogger(String loggerName) {
+			return (int) this.list.stream().filter(event -> event.getLoggerName().contains(loggerName)).count();
+		}
+
+		public List<ILoggingEvent> search(String string) {
+			return this.list.stream().filter(event -> event.toString().contains(string)).collect(Collectors.toList());
+		}
+
+		public List<ILoggingEvent> search(String string, Level level) {
+			return this.list.stream()
+				.filter(event -> event.toString().contains(string) && event.getLevel().equals(level))
+				.collect(Collectors.toList());
+		}
+
+		public int getSize() {
+			return this.list.size();
+		}
+
+		public List<ILoggingEvent> getLoggedEvents() {
+			return Collections.unmodifiableList(this.list);
+		}
+
+	}
+
 }

models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/api/tool/MockWeatherService.java

@@ -18,20 +18,24 @@
 
 import java.util.function.Function;
 
+import ch.qos.logback.classic.Logger;
 import com.fasterxml.jackson.annotation.JsonClassDescription;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonPropertyDescription;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author Christian Tzolov
  */
 public class MockWeatherService implements Function<MockWeatherService.Request, MockWeatherService.Response> {
 
+	public static final Logger log = (Logger) LoggerFactory.getLogger(MockWeatherService.class.getName());
+
 	@Override
 	public Response apply(Request request) {
-
+		log.info("Weather Request: {}", request.toString());
 		double temperature = 0;
 		if (request.location().contains("Paris")) {
 			temperature = 15;