diff --git a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/DefaultToolCallingObservationConventionTests.java b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/DefaultToolCallingObservationConventionTests.java
index 788472384a4..46727be7ab0 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/DefaultToolCallingObservationConventionTests.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/DefaultToolCallingObservationConventionTests.java
@@ -98,4 +98,47 @@ void shouldHaveHighCardinalityKeyValues() {
 						"{}"));
 	}
 
+	@Test
+	void shouldHaveAllStandardLowCardinalityKeys() {
+		ToolCallingObservationContext observationContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("tool").description("Tool").inputSchema("{}").build())
+			.toolCallArguments("args")
+			.build();
+
+		var lowCardinalityKeys = this.observationConvention.getLowCardinalityKeyValues(observationContext);
+
+		// Verify all expected low cardinality keys are present
+		assertThat(lowCardinalityKeys).extracting(KeyValue::getKey)
+			.contains(ToolCallingObservationDocumentation.LowCardinalityKeyNames.TOOL_DEFINITION_NAME.asString(),
+					ToolCallingObservationDocumentation.LowCardinalityKeyNames.AI_OPERATION_TYPE.asString(),
+					ToolCallingObservationDocumentation.LowCardinalityKeyNames.AI_PROVIDER.asString(),
+					ToolCallingObservationDocumentation.LowCardinalityKeyNames.SPRING_AI_KIND.asString());
+	}
+
+	@Test
+	void shouldHandleNullContext() {
+		assertThat(this.observationConvention.supportsContext(null)).isFalse();
+	}
+
+	@Test
+	void shouldBeConsistentAcrossMultipleCalls() {
+		ToolCallingObservationContext observationContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder()
+				.name("consistentTool")
+				.description("Consistent description")
+				.inputSchema("{}")
+				.build())
+			.toolCallArguments("args")
+			.build();
+
+		// Call multiple times and verify consistency
+		String name1 = this.observationConvention.getContextualName(observationContext);
+		String name2 = this.observationConvention.getContextualName(observationContext);
+		var lowCard1 = this.observationConvention.getLowCardinalityKeyValues(observationContext);
+		var lowCard2 = this.observationConvention.getLowCardinalityKeyValues(observationContext);
+
+		assertThat(name1).isEqualTo(name2);
+		assertThat(lowCard1).isEqualTo(lowCard2);
+	}
+
 }
diff --git a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingContentObservationFilterTests.java b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingContentObservationFilterTests.java
index f64ab4010ed..c10a144b9e4 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingContentObservationFilterTests.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingContentObservationFilterTests.java
@@ -74,4 +74,62 @@ void augmentContextWhenNullResult() {
 			.isEmpty();
 	}
 
+	@Test
+	void whenToolCallArgumentsIsEmptyStringThenHighCardinalityKeyValueIsEmpty() {
+		var originalContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallArguments("")
+			.toolCallResult("result")
+			.build();
+		var augmentedContext = this.observationFilter.map(originalContext);
+
+		assertThat(augmentedContext.getHighCardinalityKeyValues()).contains(KeyValue
+			.of(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_ARGUMENTS.asString(), ""));
+		assertThat(augmentedContext.getHighCardinalityKeyValues()).contains(KeyValue
+			.of(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_RESULT.asString(), "result"));
+	}
+
+	@Test
+	void whenToolCallResultIsEmptyStringThenHighCardinalityKeyValueIsEmpty() {
+		var originalContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallArguments("input")
+			.toolCallResult("")
+			.build();
+		var augmentedContext = this.observationFilter.map(originalContext);
+
+		assertThat(augmentedContext.getHighCardinalityKeyValues()).contains(KeyValue
+			.of(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_ARGUMENTS.asString(), "input"));
+		assertThat(augmentedContext.getHighCardinalityKeyValues()).contains(KeyValue
+			.of(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_RESULT.asString(), ""));
+	}
+
+	@Test
+	void whenFilterAppliedMultipleTimesThenIdempotent() {
+		var originalContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallArguments("input")
+			.toolCallResult("result")
+			.build();
+
+		var augmentedOnce = this.observationFilter.map(originalContext);
+		var augmentedTwice = this.observationFilter.map(augmentedOnce);
+
+		// Count occurrences of each key
+		long argumentsCount = augmentedTwice.getHighCardinalityKeyValues()
+			.stream()
+			.filter(kv -> kv.getKey()
+				.equals(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_ARGUMENTS.asString()))
+			.count();
+		long resultCount = augmentedTwice.getHighCardinalityKeyValues()
+			.stream()
+			.filter(kv -> kv.getKey()
+				.equals(ToolCallingObservationDocumentation.HighCardinalityKeyNames.TOOL_CALL_RESULT.asString()))
+			.count();
+
+		// Should not duplicate keys
+		assertThat(argumentsCount).isEqualTo(1);
+		assertThat(resultCount).isEqualTo(1);
+	}
+
 }
diff --git a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingObservationContextTests.java b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingObservationContextTests.java
index 44f3aabaf6d..f888cce6703 100644
--- a/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingObservationContextTests.java
+++ b/spring-ai-model/src/test/java/org/springframework/ai/tool/observation/ToolCallingObservationContextTests.java
@@ -74,4 +74,50 @@ void whenToolMetadataIsNullThenThrow() {
 			.build()).isInstanceOf(IllegalArgumentException.class).hasMessageContaining("toolMetadata cannot be null");
 	}
 
+	@Test
+	void whenToolArgumentsIsEmptyStringThenReturnEmptyString() {
+		var observationContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallArguments("")
+			.build();
+		assertThat(observationContext).isNotNull();
+		assertThat(observationContext.getToolCallArguments()).isEqualTo("");
+	}
+
+	@Test
+	void whenToolCallResultIsNullThenReturnNull() {
+		var observationContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallResult(null)
+			.build();
+		assertThat(observationContext).isNotNull();
+		assertThat(observationContext.getToolCallResult()).isNull();
+	}
+
+	@Test
+	void whenToolCallResultIsEmptyStringThenReturnEmptyString() {
+		var observationContext = ToolCallingObservationContext.builder()
+			.toolDefinition(ToolDefinition.builder().name("toolA").description("description").inputSchema("{}").build())
+			.toolCallResult("")
+			.build();
+		assertThat(observationContext).isNotNull();
+		assertThat(observationContext.getToolCallResult()).isEqualTo("");
+	}
+
+	@Test
+	void whenToolDefinitionIsSetThenGetReturnsIt() {
+		var toolDef = ToolDefinition.builder()
+			.name("testTool")
+			.description("Test description")
+			.inputSchema("{\"type\": \"object\"}")
+			.build();
+
+		var observationContext = ToolCallingObservationContext.builder().toolDefinition(toolDef).build();
+
+		assertThat(observationContext.getToolDefinition()).isEqualTo(toolDef);
+		assertThat(observationContext.getToolDefinition().name()).isEqualTo("testTool");
+		assertThat(observationContext.getToolDefinition().description()).isEqualTo("Test description");
+		assertThat(observationContext.getToolDefinition().inputSchema()).isEqualTo("{\"type\": \"object\"}");
+	}
+
 }