Prompt content and completion as span events

Signed-off-by: Thomas Vitale <ThomasVitale@users.noreply.github.com>

spring-ai-core/pom.xml

@@ -84,6 +84,12 @@
 			<artifactId>micrometer-core</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>io.micrometer</groupId>
+			<artifactId>micrometer-tracing-bridge-otel</artifactId>
+			<optional>true</optional>
+		</dependency>
+
 		<dependency>
 			<groupId>com.knuddels</groupId>
 			<artifactId>jtokkit</artifactId>

spring-ai-core/src/main/java/org/springframework/ai/chat/observation/ChatModelCompletionObservationFilter.java

@@ -17,10 +17,6 @@ package org.springframework.ai.chat.observation;
 
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationFilter;
-import org.springframework.util.CollectionUtils;
-import org.springframework.util.StringUtils;
-
-import java.util.StringJoiner;
 
 /**
  * An {@link ObservationFilter} to include the chat completion content in the observation.
@@ -36,25 +32,11 @@ public class ChatModelCompletionObservationFilter implements ObservationFilter {
 			return context;
 		}
 
-		if (chatModelObservationContext.getResponse() == null
-				|| chatModelObservationContext.getResponse().getResults() == null
-				|| CollectionUtils.isEmpty(chatModelObservationContext.getResponse().getResults())) {
-			return chatModelObservationContext;
-		}
+		var completions = ChatModelObservationContentProcessor.completion(chatModelObservationContext);
 
-		StringJoiner completionChoicesJoiner = new StringJoiner(", ", "[", "]");
-		chatModelObservationContext.getResponse()
-			.getResults()
-			.stream()
-			.filter(generation -> generation.getOutput() != null
-					&& StringUtils.hasText(generation.getOutput().getContent()))
-			.forEach(generation -> completionChoicesJoiner.add("\"" + generation.getOutput().getContent() + "\""));
-
-		if (StringUtils.hasText(chatModelObservationContext.getResponse().getResult().getOutput().getContent())) {
-			chatModelObservationContext
-				.addHighCardinalityKeyValue(ChatModelObservationDocumentation.HighCardinalityKeyNames.COMPLETION
-					.withValue(completionChoicesJoiner.toString()));
-		}
+		chatModelObservationContext
+			.addHighCardinalityKeyValue(ChatModelObservationDocumentation.HighCardinalityKeyNames.COMPLETION
+				.withValue(ChatModelObservationContentProcessor.concatenateStrings(completions)));
 
 		return chatModelObservationContext;
 	}

spring-ai-core/src/main/java/org/springframework/ai/chat/observation/ChatModelCompletionObservationHandler.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationHandler;
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.Span;
+import org.springframework.ai.observation.conventions.AiObservationAttributes;
+import org.springframework.ai.observation.conventions.AiObservationEventNames;
+
+/**
+ * Handler for including the chat completion content in the observation as a span event.
+ *
+ * @author Thomas Vitale
+ * @since 1.0.0
+ */
+public class ChatModelCompletionObservationHandler implements ObservationHandler<ChatModelObservationContext> {
+
+	@Override
+	public void onStop(ChatModelObservationContext context) {
+		TracingObservationHandler.TracingContext tracingContext = context
+			.get(TracingObservationHandler.TracingContext.class);
+		Span otelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+
+		if (otelSpan != null) {
+			otelSpan.addEvent(AiObservationEventNames.CONTENT_COMPLETION.value(),
+					Attributes.of(AttributeKey.stringArrayKey(AiObservationAttributes.COMPLETION.value()),
+							ChatModelObservationContentProcessor.completion(context)));
+		}
+	}
+
+	@Override
+	public boolean supportsContext(Observation.Context context) {
+		return context instanceof ChatModelObservationContext;
+	}
+
+}

spring-ai-core/src/main/java/org/springframework/ai/chat/observation/ChatModelObservationContentProcessor.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.opentelemetry.api.trace.Span;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.ai.model.Content;
+import org.springframework.lang.Nullable;
+import org.springframework.util.CollectionUtils;
+import org.springframework.util.StringUtils;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.StringJoiner;
+
+/**
+ * Utilities to process the prompt and completion content in observations for chat models.
+ *
+ * @author Thomas Vitale
+ */
+public final class ChatModelObservationContentProcessor {
+
+	private static final Logger logger = LoggerFactory.getLogger(ChatModelObservationContentProcessor.class);
+
+	public static List<String> prompt(ChatModelObservationContext context) {
+		if (CollectionUtils.isEmpty(context.getRequest().getInstructions())) {
+			return List.of();
+		}
+
+		return context.getRequest().getInstructions().stream().map(Content::getContent).toList();
+	}
+
+	public static List<String> completion(ChatModelObservationContext context) {
+		if (context == null || context.getResponse() == null || context.getResponse().getResults() == null
+				|| CollectionUtils.isEmpty(context.getResponse().getResults())) {
+			return List.of();
+		}
+
+		if (!StringUtils.hasText(context.getResponse().getResult().getOutput().getContent())) {
+			return List.of();
+		}
+
+		return context.getResponse()
+			.getResults()
+			.stream()
+			.filter(generation -> generation.getOutput() != null
+					&& StringUtils.hasText(generation.getOutput().getContent()))
+			.map(generation -> generation.getOutput().getContent())
+			.toList();
+	}
+
+	public static String concatenateStrings(List<String> strings) {
+		var promptMessagesJoiner = new StringJoiner(", ", "[", "]");
+		strings.forEach(string -> promptMessagesJoiner.add("\"" + string + "\""));
+		return promptMessagesJoiner.toString();
+	}
+
+	@Nullable
+	public static Span extractOtelSpan(@Nullable TracingObservationHandler.TracingContext tracingContext) {
+		if (tracingContext == null) {
+			return null;
+		}
+
+		io.micrometer.tracing.Span micrometerSpan = tracingContext.getSpan();
+		try {
+			Method toOtelMethod = tracingContext.getSpan()
+				.getClass()
+				.getDeclaredMethod("toOtel", io.micrometer.tracing.Span.class);
+			toOtelMethod.setAccessible(true);
+			Object otelSpanObject = toOtelMethod.invoke(null, micrometerSpan);
+			if (otelSpanObject instanceof Span otelSpan) {
+				return otelSpan;
+			}
+		}
+		catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException ex) {
+			logger.warn("It wasn't possible to extract the OpenTelemetry Span object from Micrometer", ex);
+			return null;
+		}
+
+		return null;
+	}
+
+}

spring-ai-core/src/main/java/org/springframework/ai/chat/observation/ChatModelPromptContentObservationFilter.java

@@ -17,9 +17,6 @@ package org.springframework.ai.chat.observation;
 
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationFilter;
-import org.springframework.util.CollectionUtils;
-
-import java.util.StringJoiner;
 
 /**
  * An {@link ObservationFilter} to include the chat prompt content in the observation.
@@ -35,18 +32,11 @@ public class ChatModelPromptContentObservationFilter implements ObservationFilte
 			return context;
 		}
 
-		if (CollectionUtils.isEmpty(chatModelObservationContext.getRequest().getInstructions())) {
-			return chatModelObservationContext;
-		}
-
-		StringJoiner promptMessagesJoiner = new StringJoiner(", ", "[", "]");
-		chatModelObservationContext.getRequest()
-			.getInstructions()
-			.forEach(message -> promptMessagesJoiner.add("\"" + message.getContent() + "\""));
+		var prompts = ChatModelObservationContentProcessor.prompt(chatModelObservationContext);
 
 		chatModelObservationContext
 			.addHighCardinalityKeyValue(ChatModelObservationDocumentation.HighCardinalityKeyNames.PROMPT
-				.withValue(promptMessagesJoiner.toString()));
+				.withValue(ChatModelObservationContentProcessor.concatenateStrings(prompts)));
 
 		return chatModelObservationContext;
 	}

spring-ai-core/src/main/java/org/springframework/ai/chat/observation/ChatModelPromptContentObservationHandler.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationHandler;
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.Span;
+import org.springframework.ai.observation.conventions.AiObservationAttributes;
+import org.springframework.ai.observation.conventions.AiObservationEventNames;
+
+/**
+ * Handler for including the chat prompt content in the observation as a span event.
+ *
+ * @author Thomas Vitale
+ * @since 1.0.0
+ */
+public class ChatModelPromptContentObservationHandler implements ObservationHandler<ChatModelObservationContext> {
+
+	@Override
+	public void onStop(ChatModelObservationContext context) {
+		TracingObservationHandler.TracingContext tracingContext = context
+			.get(TracingObservationHandler.TracingContext.class);
+		Span otelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+
+		if (otelSpan != null) {
+			otelSpan.addEvent(AiObservationEventNames.CONTENT_PROMPT.value(),
+					Attributes.of(AttributeKey.stringArrayKey(AiObservationAttributes.PROMPT.value()),
+							ChatModelObservationContentProcessor.prompt(context)));
+		}
+
+	}
+
+	@Override
+	public boolean supportsContext(Observation.Context context) {
+		return context instanceof ChatModelObservationContext;
+	}
+
+}

spring-ai-core/src/test/java/org/springframework/ai/chat/observation/ChatModelCompletionObservationHandlerTests.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.micrometer.tracing.otel.bridge.OtelCurrentTraceContext;
+import io.micrometer.tracing.otel.bridge.OtelTracer;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.sdk.trace.ReadableSpan;
+import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import org.junit.jupiter.api.Test;
+import org.springframework.ai.chat.messages.AssistantMessage;
+import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.model.Generation;
+import org.springframework.ai.chat.prompt.ChatOptionsBuilder;
+import org.springframework.ai.chat.prompt.Prompt;
+import org.springframework.ai.observation.conventions.AiObservationAttributes;
+import org.springframework.ai.observation.conventions.AiObservationEventNames;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link ChatModelCompletionObservationHandler}.
+ *
+ * @author Thomas Vitale
+ */
+class ChatModelCompletionObservationHandlerTests {
+
+	@Test
+	void whenCompletionWithTextThenSpanEvent() {
+		var observationContext = ChatModelObservationContext.builder()
+			.prompt(new Prompt("supercalifragilisticexpialidocious"))
+			.provider("mary-poppins")
+			.requestOptions(ChatOptionsBuilder.builder().withModel("spoonful-of-sugar").build())
+			.build();
+		observationContext.setResponse(new ChatResponse(List.of(new Generation(new AssistantMessage("say please")),
+				new Generation(new AssistantMessage("seriously, say please")))));
+		var sdkTracer = SdkTracerProvider.builder().build().get("test");
+		var otelTracer = new OtelTracer(sdkTracer, new OtelCurrentTraceContext(), null);
+		var span = otelTracer.nextSpan();
+		var tracingContext = new TracingObservationHandler.TracingContext();
+		tracingContext.setSpan(span);
+		observationContext.put(TracingObservationHandler.TracingContext.class, tracingContext);
+
+		new ChatModelCompletionObservationHandler().onStop(observationContext);
+
+		var otelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+		assertThat(otelSpan).isNotNull();
+		var spanData = ((ReadableSpan) otelSpan).toSpanData();
+		assertThat(spanData.getEvents().size()).isEqualTo(1);
+		assertThat(spanData.getEvents().get(0).getName()).isEqualTo(AiObservationEventNames.CONTENT_COMPLETION.value());
+		assertThat(spanData.getEvents()
+			.get(0)
+			.getAttributes()
+			.get(AttributeKey.stringArrayKey(AiObservationAttributes.COMPLETION.value())))
+			.containsOnly("say please", "seriously, say please");
+	}
+
+}

spring-ai-core/src/test/java/org/springframework/ai/chat/observation/ChatModelObservationContentProcessorTests.java

@@ -0,0 +1,142 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.tracing.Span;
+import io.micrometer.tracing.TraceContext;
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.micrometer.tracing.otel.bridge.OtelCurrentTraceContext;
+import io.micrometer.tracing.otel.bridge.OtelTracer;
+import io.opentelemetry.api.OpenTelemetry;
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link ChatModelObservationContentProcessor}.
+ *
+ * @author Thomas Vitale
+ */
+class ChatModelObservationContentProcessorTests {
+
+	@Test
+	void extractOtelSpanWhenTracingContextIsNull() {
+		var actualOtelSpan = ChatModelObservationContentProcessor.extractOtelSpan(null);
+		assertThat(actualOtelSpan).isNull();
+	}
+
+	@Test
+	void extractOtelSpanWhenMethodDoesNotExist() {
+		var tracingContext = new TracingObservationHandler.TracingContext();
+		tracingContext.setSpan(Span.NOOP);
+		var actualOtelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+		assertThat(actualOtelSpan).isNull();
+	}
+
+	@Test
+	void extractOtelSpanWhenSpanIsNotOpenTelemetry() {
+		var tracingContext = new TracingObservationHandler.TracingContext();
+		tracingContext.setSpan(new DemoOtherSpan());
+		var actualOtelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+		assertThat(actualOtelSpan).isNull();
+	}
+
+	@Test
+	void extractOtelSpanWhenSpanIsOpenTelemetry() {
+		var tracingContext = new TracingObservationHandler.TracingContext();
+		var otelTracer = new OtelTracer(OpenTelemetry.noop().getTracer("test"), new OtelCurrentTraceContext(), null);
+		tracingContext.setSpan(otelTracer.nextSpan());
+		var actualOtelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+		assertThat(actualOtelSpan).isNotNull();
+		assertThat(actualOtelSpan).isInstanceOf(io.opentelemetry.api.trace.Span.class);
+	}
+
+	static class DemoOtherSpan implements Span {
+
+		private static Span toOtel(Span span) {
+			return Span.NOOP;
+		}
+
+		@Override
+		public boolean isNoop() {
+			return false;
+		}
+
+		@Override
+		public TraceContext context() {
+			return null;
+		}
+
+		@Override
+		public Span start() {
+			return null;
+		}
+
+		@Override
+		public Span name(String s) {
+			return null;
+		}
+
+		@Override
+		public Span event(String s) {
+			return null;
+		}
+
+		@Override
+		public Span event(String s, long l, TimeUnit timeUnit) {
+			return null;
+		}
+
+		@Override
+		public Span tag(String s, String s1) {
+			return null;
+		}
+
+		@Override
+		public Span error(Throwable throwable) {
+			return null;
+		}
+
+		@Override
+		public void end() {
+
+		}
+
+		@Override
+		public void end(long l, TimeUnit timeUnit) {
+
+		}
+
+		@Override
+		public void abandon() {
+
+		}
+
+		@Override
+		public Span remoteServiceName(String s) {
+			return null;
+		}
+
+		@Override
+		public Span remoteIpAndPort(String s, int i) {
+			return null;
+		}
+
+	}
+
+}

spring-ai-core/src/test/java/org/springframework/ai/chat/observation/ChatModelPromptContentObservationHandlerTests.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.chat.observation;
+
+import io.micrometer.tracing.handler.TracingObservationHandler;
+import io.micrometer.tracing.otel.bridge.OtelCurrentTraceContext;
+import io.micrometer.tracing.otel.bridge.OtelTracer;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.sdk.trace.ReadableSpan;
+import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import org.junit.jupiter.api.Test;
+import org.springframework.ai.chat.prompt.ChatOptionsBuilder;
+import org.springframework.ai.chat.prompt.Prompt;
+import org.springframework.ai.observation.conventions.AiObservationAttributes;
+import org.springframework.ai.observation.conventions.AiObservationEventNames;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link ChatModelPromptContentObservationHandler}.
+ *
+ * @author Thomas Vitale
+ */
+class ChatModelPromptContentObservationHandlerTests {
+
+	@Test
+	void whenPromptWithTextThenSpanEvent() {
+		var observationContext = ChatModelObservationContext.builder()
+			.prompt(new Prompt("supercalifragilisticexpialidocious"))
+			.provider("mary-poppins")
+			.requestOptions(ChatOptionsBuilder.builder().withModel("spoonful-of-sugar").build())
+			.build();
+		var sdkTracer = SdkTracerProvider.builder().build().get("test");
+		var otelTracer = new OtelTracer(sdkTracer, new OtelCurrentTraceContext(), null);
+		var span = otelTracer.nextSpan();
+		var tracingContext = new TracingObservationHandler.TracingContext();
+		tracingContext.setSpan(span);
+		observationContext.put(TracingObservationHandler.TracingContext.class, tracingContext);
+
+		new ChatModelPromptContentObservationHandler().onStop(observationContext);
+
+		var otelSpan = ChatModelObservationContentProcessor.extractOtelSpan(tracingContext);
+		assertThat(otelSpan).isNotNull();
+		var spanData = ((ReadableSpan) otelSpan).toSpanData();
+		assertThat(spanData.getEvents().size()).isEqualTo(1);
+		assertThat(spanData.getEvents().get(0).getName()).isEqualTo(AiObservationEventNames.CONTENT_PROMPT.value());
+		assertThat(spanData.getEvents()
+			.get(0)
+			.getAttributes()
+			.get(AttributeKey.stringArrayKey(AiObservationAttributes.PROMPT.value())))
+			.containsOnly("supercalifragilisticexpialidocious");
+	}
+
+}

spring-ai-spring-boot-autoconfigure/pom.xml

@@ -36,6 +36,12 @@
 			<artifactId>spring-boot-starter</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>io.micrometer</groupId>
+			<artifactId>micrometer-tracing-bridge-otel</artifactId>
+			<optional>true</optional>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.ai</groupId>
 			<artifactId>spring-ai-openai</artifactId>

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/chat/observation/ChatObservationAutoConfiguration.java

@@ -16,20 +16,25 @@
 package org.springframework.ai.autoconfigure.chat.observation;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.tracing.otel.bridge.OtelTracer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.ai.chat.model.ChatModel;
 import org.springframework.ai.chat.observation.ChatModelCompletionObservationFilter;
+import org.springframework.ai.chat.observation.ChatModelCompletionObservationHandler;
 import org.springframework.ai.chat.observation.ChatModelMeterObservationHandler;
 import org.springframework.ai.chat.observation.ChatModelPromptContentObservationFilter;
+import org.springframework.ai.chat.observation.ChatModelPromptContentObservationHandler;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 /**
  * Auto-configuration for Spring AI chat model observations.
@@ -52,24 +57,70 @@ public class ChatObservationAutoConfiguration {
 		return new ChatModelMeterObservationHandler(meterRegistry.getObject());
 	}
 
-	@Bean
-	@ConditionalOnMissingBean
-	@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-prompt",
-			havingValue = "true")
-	ChatModelPromptContentObservationFilter chatModelPromptObservationFilter() {
-		logger.warn(
-				"You have enabled the inclusion of the prompt content in the observations, with the risk of exposing sensitive or private information. Please, be careful!");
-		return new ChatModelPromptContentObservationFilter();
+	/**
+	 * The chat content is typically too big to be included in an observation as span
+	 * attributes. That's why the preferred way to store it is as span events, which are
+	 * supported by OpenTelemetry but not yet surfaced through the Micrometer APIs. This
+	 * primary/fallback configuration is a temporary solution until
+	 * https://github.com/micrometer-metrics/micrometer/issues/5238 is delivered.
+	 */
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass(OtelTracer.class)
+	@ConditionalOnBean(OtelTracer.class)
+	static class PrimaryChatContentObservationConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean
+		@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-prompt",
+				havingValue = "true")
+		ChatModelPromptContentObservationHandler chatModelPromptContentObservationHandler() {
+			logPromptContentWarning();
+			return new ChatModelPromptContentObservationHandler();
+		}
+
+		@Bean
+		@ConditionalOnMissingBean
+		@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-completion",
+				havingValue = "true")
+		ChatModelCompletionObservationHandler chatModelCompletionObservationHandler() {
+			logCompletionWarning();
+			return new ChatModelCompletionObservationHandler();
+		}
+
 	}
 
-	@Bean
-	@ConditionalOnMissingBean
-	@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-completion",
-			havingValue = "true")
-	ChatModelCompletionObservationFilter chatModelCompletionObservationFilter() {
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnMissingClass("io.micrometer.tracing.otel.bridge.OtelTracer")
+	static class FallbackChatContentObservationConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean
+		@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-prompt",
+				havingValue = "true")
+		ChatModelPromptContentObservationFilter chatModelPromptObservationFilter() {
+			logPromptContentWarning();
+			return new ChatModelPromptContentObservationFilter();
+		}
+
+		@Bean
+		@ConditionalOnMissingBean
+		@ConditionalOnProperty(prefix = ChatObservationProperties.CONFIG_PREFIX, name = "include-completion",
+				havingValue = "true")
+		ChatModelCompletionObservationFilter chatModelCompletionObservationFilter() {
+			logCompletionWarning();
+			return new ChatModelCompletionObservationFilter();
+		}
+
+	}
+
+	private static void logPromptContentWarning() {
+		logger.warn(
+				"You have enabled the inclusion of the prompt content in the observations, with the risk of exposing sensitive or private information. Please, be careful!");
+	}
+
+	private static void logCompletionWarning() {
 		logger.warn(
 				"You have enabled the inclusion of the completion content in the observations, with the risk of exposing sensitive or private information. Please, be careful!");
-		return new ChatModelCompletionObservationFilter();
 	}
 
 }

spring-ai-spring-boot-autoconfigure/src/test/java/org/springframework/ai/autoconfigure/chat/observation/ChatObservationAutoConfigurationTests.java

@@ -16,10 +16,11 @@
 package org.springframework.ai.autoconfigure.chat.observation;
 
 import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+import io.micrometer.tracing.otel.bridge.OtelCurrentTraceContext;
+import io.micrometer.tracing.otel.bridge.OtelTracer;
+import io.opentelemetry.api.OpenTelemetry;
 import org.junit.jupiter.api.Test;
-import org.springframework.ai.chat.observation.ChatModelCompletionObservationFilter;
-import org.springframework.ai.chat.observation.ChatModelMeterObservationHandler;
-import org.springframework.ai.chat.observation.ChatModelPromptContentObservationFilter;
+import org.springframework.ai.chat.observation.*;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 
@@ -57,9 +58,26 @@ class ChatObservationAutoConfigurationTests {
 	}
 
 	@Test
-	void promptFilterEnabled() {
+	void promptHandlerDefault() {
+		contextRunner.run(context -> {
+			assertThat(context).doesNotHaveBean(ChatModelPromptContentObservationHandler.class);
+		});
+	}
+
+	@Test
+	void promptHandlerEnabled() {
+		contextRunner
+			.withBean(OtelTracer.class, OpenTelemetry.noop().getTracer("test"), new OtelCurrentTraceContext(), null)
+			.withPropertyValues("spring.ai.chat.observations.include-prompt=true")
+			.run(context -> {
+				assertThat(context).hasSingleBean(ChatModelPromptContentObservationHandler.class);
+			});
+	}
+
+	@Test
+	void promptHandlerDisabled() {
 		contextRunner.withPropertyValues("spring.ai.chat.observations.include-prompt=true").run(context -> {
-			assertThat(context).hasSingleBean(ChatModelPromptContentObservationFilter.class);
+			assertThat(context).doesNotHaveBean(ChatModelPromptContentObservationHandler.class);
 		});
 	}
 
@@ -71,9 +89,26 @@ class ChatObservationAutoConfigurationTests {
 	}
 
 	@Test
-	void completionFilterEnabled() {
+	void completionHandlerDefault() {
+		contextRunner.run(context -> {
+			assertThat(context).doesNotHaveBean(ChatModelCompletionObservationHandler.class);
+		});
+	}
+
+	@Test
+	void completionHandlerEnabled() {
+		contextRunner
+			.withBean(OtelTracer.class, OpenTelemetry.noop().getTracer("test"), new OtelCurrentTraceContext(), null)
+			.withPropertyValues("spring.ai.chat.observations.include-completion=true")
+			.run(context -> {
+				assertThat(context).hasSingleBean(ChatModelCompletionObservationHandler.class);
+			});
+	}
+
+	@Test
+	void completionHandlerDisabled() {
 		contextRunner.withPropertyValues("spring.ai.chat.observations.include-completion=true").run(context -> {
-			assertThat(context).hasSingleBean(ChatModelCompletionObservationFilter.class);
+			assertThat(context).doesNotHaveBean(ChatModelCompletionObservationHandler.class);
 		});
 	}