diff --git a/spring-ai-model/src/test/java/org/springframework/ai/image/observation/DefaultImageModelObservationConventionTests.java b/spring-ai-model/src/test/java/org/springframework/ai/image/observation/DefaultImageModelObservationConventionTests.java
index f75fb4961f5..a0c2c4a8305 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/image/observation/DefaultImageModelObservationConventionTests.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/image/observation/DefaultImageModelObservationConventionTests.java
@@ -120,6 +120,83 @@ void shouldNotHaveKeyValuesWhenEmptyValues() {
 					HighCardinalityKeyNames.REQUEST_IMAGE_STYLE.asString());
 	}
 
+	@Test
+	void shouldHandleNullModel() {
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(new ImagePrompt("test prompt"))
+			.provider("test-provider")
+			.build();
+
+		assertThat(this.observationConvention.getContextualName(observationContext)).isEqualTo("image");
+		assertThat(this.observationConvention.getLowCardinalityKeyValues(observationContext))
+			.contains(KeyValue.of(AiObservationAttributes.REQUEST_MODEL.value(), KeyValue.NONE_VALUE));
+	}
+
+	@Test
+	void shouldHandleEmptyModel() {
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(generateImagePrompt(ImageOptionsBuilder.builder().model("").build()))
+			.provider("test-provider")
+			.build();
+
+		assertThat(this.observationConvention.getContextualName(observationContext)).isEqualTo("image");
+	}
+
+	@Test
+	void shouldHandleBlankModel() {
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(generateImagePrompt(ImageOptionsBuilder.builder().model("   ").build()))
+			.provider("test-provider")
+			.build();
+
+		assertThat(this.observationConvention.getContextualName(observationContext)).isEqualTo("image");
+	}
+
+	@Test
+	void shouldHandleEmptyStyle() {
+		var imageOptions = ImageOptionsBuilder.builder().model("test-model").style("").build();
+
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(generateImagePrompt(imageOptions))
+			.provider("test-provider")
+			.build();
+
+		// Empty style should not be included
+		assertThat(this.observationConvention.getHighCardinalityKeyValues(observationContext)
+			.stream()
+			.map(KeyValue::getKey)
+			.toList()).doesNotContain(HighCardinalityKeyNames.REQUEST_IMAGE_STYLE.asString());
+	}
+
+	@Test
+	void shouldHandleEmptyResponseFormat() {
+		var imageOptions = ImageOptionsBuilder.builder().model("test-model").responseFormat("").build();
+
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(generateImagePrompt(imageOptions))
+			.provider("test-provider")
+			.build();
+
+		// Empty response format should not be included
+		assertThat(this.observationConvention.getHighCardinalityKeyValues(observationContext)
+			.stream()
+			.map(KeyValue::getKey)
+			.toList()).doesNotContain(HighCardinalityKeyNames.REQUEST_IMAGE_RESPONSE_FORMAT.asString());
+	}
+
+	@Test
+	void shouldHandleImagePromptWithoutOptions() {
+		ImageModelObservationContext observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(new ImagePrompt("simple prompt"))
+			.provider("simple-provider")
+			.build();
+
+		assertThat(this.observationConvention.getContextualName(observationContext)).isEqualTo("image");
+		assertThat(this.observationConvention.getLowCardinalityKeyValues(observationContext))
+			.contains(KeyValue.of(AiObservationAttributes.REQUEST_MODEL.value(), KeyValue.NONE_VALUE));
+		assertThat(this.observationConvention.getHighCardinalityKeyValues(observationContext)).isEmpty();
+	}
+
 	private ImagePrompt generateImagePrompt(ImageOptions imageOptions) {
 		return new ImagePrompt("here comes the sun", imageOptions);
 	}
diff --git a/spring-ai-model/src/test/java/org/springframework/ai/image/observation/ImageModelObservationContextTests.java b/spring-ai-model/src/test/java/org/springframework/ai/image/observation/ImageModelObservationContextTests.java
index 36b06a1f52c..cfda9898b93 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/image/observation/ImageModelObservationContextTests.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/image/observation/ImageModelObservationContextTests.java
@@ -23,6 +23,7 @@
 import org.springframework.ai.image.ImagePrompt;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * Unit tests for {@link ImageModelObservationContext}.
@@ -41,6 +42,75 @@ void whenMandatoryRequestOptionsThenReturn() {
 		assertThat(observationContext).isNotNull();
 	}
 
+	@Test
+	void shouldBuildContextWithImageOptions() {
+		var imageOptions = ImageOptionsBuilder.builder().model("test-model").build();
+		var imagePrompt = new ImagePrompt("test prompt", imageOptions);
+
+		var observationContext = ImageModelObservationContext.builder()
+			.imagePrompt(imagePrompt)
+			.provider("test-provider")
+			.build();
+
+		assertThat(observationContext).isNotNull();
+	}
+
+	@Test
+	void shouldThrowExceptionWhenImagePromptIsNull() {
+		assertThatThrownBy(
+				() -> ImageModelObservationContext.builder().imagePrompt(null).provider("test-provider").build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("request cannot be null");
+	}
+
+	@Test
+	void shouldThrowExceptionWhenProviderIsNull() {
+		var imagePrompt = new ImagePrompt("test prompt");
+
+		assertThatThrownBy(() -> ImageModelObservationContext.builder().imagePrompt(imagePrompt).provider(null).build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("provider cannot be null or empty");
+	}
+
+	@Test
+	void shouldThrowExceptionWhenProviderIsEmpty() {
+		var imagePrompt = new ImagePrompt("test prompt");
+
+		assertThatThrownBy(() -> ImageModelObservationContext.builder().imagePrompt(imagePrompt).provider("").build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("provider cannot be null or empty");
+	}
+
+	@Test
+	void shouldThrowExceptionWhenProviderIsBlank() {
+		var imagePrompt = new ImagePrompt("test prompt");
+
+		assertThatThrownBy(
+				() -> ImageModelObservationContext.builder().imagePrompt(imagePrompt).provider("   ").build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("provider cannot be null or empty");
+	}
+
+	@Test
+	void shouldBuildMultipleContextsIndependently() {
+		var imagePrompt1 = new ImagePrompt("first prompt");
+		var imagePrompt2 = new ImagePrompt("second prompt");
+
+		var context1 = ImageModelObservationContext.builder()
+			.imagePrompt(imagePrompt1)
+			.provider("provider-alpha")
+			.build();
+
+		var context2 = ImageModelObservationContext.builder()
+			.imagePrompt(imagePrompt2)
+			.provider("provider-beta")
+			.build();
+
+		assertThat(context1).isNotNull();
+		assertThat(context2).isNotNull();
+		assertThat(context1).isNotEqualTo(context2);
+	}
+
 	private ImagePrompt generateImagePrompt(ImageOptions imageOptions) {
 		return new ImagePrompt("here comes the sun");
 	}
diff --git a/spring-ai-model/src/test/java/org/springframework/ai/tool/function/FunctionToolCallbackTest.java b/spring-ai-model/src/test/java/org/springframework/ai/tool/function/FunctionToolCallbackTest.java
index 707ab490154..4c3361d25e0 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/tool/function/FunctionToolCallbackTest.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/tool/function/FunctionToolCallbackTest.java
@@ -138,6 +138,18 @@ void testThrowToolExecutionException() {
 			.isInstanceOf(ToolExecutionException.class);
 	}
 
+	@Test
+	void testEmptyStringInput() {
+		TestFunctionTool tool = new TestFunctionTool();
+		FunctionToolCallback<String, Void> callback = FunctionToolCallback.builder("testTool", tool.stringConsumer())
+			.description("test empty string")
+			.inputType(String.class)
+			.build();
+
+		callback.call("\"\"");
+		assertEquals("", tool.calledValue.get());
+	}
+
 	static class TestFunctionTool {
 
 		AtomicReference<Object> calledValue = new AtomicReference<>();