diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
index d0476e5f2..83aa8f5ba 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
@@ -26,7 +26,6 @@
 import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
 import io.modelcontextprotocol.spec.McpSchema.CompleteResult.CompleteCompletion;
 import io.modelcontextprotocol.spec.McpSchema.ErrorCodes;
-import io.modelcontextprotocol.spec.McpSchema.LoggingLevel;
 import io.modelcontextprotocol.spec.McpSchema.PromptReference;
 import io.modelcontextprotocol.spec.McpSchema.ResourceReference;
 import io.modelcontextprotocol.spec.McpSchema.SetLevelRequest;
@@ -433,9 +432,11 @@ public Mono<CallToolResult> apply(McpAsyncServerExchange exchange, McpSchema.Cal
 				var validation = this.jsonSchemaValidator.validate(outputSchema, result.structuredContent());
 
 				if (!validation.valid()) {
-					logger.warn("Tool call result validation failed: {}", validation.errorMessage());
+					String message = "Tool (" + request.name() + ") output validation failed: "
+							+ validation.errorMessage();
+					logger.warn(message);
 					return CallToolResult.builder()
-						.content(List.of(McpSchema.TextContent.builder(validation.errorMessage()).build()))
+						.content(List.of(McpSchema.TextContent.builder(message).build()))
 						.isError(true)
 						.build();
 				}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java
index 48b17ed2a..c6105267d 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpStatelessAsyncServer.java
@@ -4,9 +4,19 @@
 
 package io.modelcontextprotocol.server;
 
-import io.modelcontextprotocol.json.TypeRef;
-import io.modelcontextprotocol.json.McpJsonMapper;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.BiFunction;
+
 import io.modelcontextprotocol.common.McpTransportContext;
+import io.modelcontextprotocol.json.McpJsonMapper;
+import io.modelcontextprotocol.json.TypeRef;
 import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
 import io.modelcontextprotocol.server.McpStatelessServerFeatures.AsyncResourceTemplateSpecification;
 import io.modelcontextprotocol.spec.McpError;
@@ -28,16 +38,6 @@
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
-import java.time.Duration;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.function.BiFunction;
-
 import static io.modelcontextprotocol.spec.McpError.RESOURCE_NOT_FOUND;
 
 /**
@@ -293,9 +293,11 @@ public Mono<CallToolResult> apply(McpTransportContext transportContext, McpSchem
 				var validation = this.jsonSchemaValidator.validate(outputSchema, result.structuredContent());
 
 				if (!validation.valid()) {
-					logger.warn("Tool call result validation failed: {}", validation.errorMessage());
+					String message = "Tool (" + request.name() + ") output validation failed: "
+							+ validation.errorMessage();
+					logger.warn(message);
 					return CallToolResult.builder()
-						.content(List.of(McpSchema.TextContent.builder(validation.errorMessage()).build()))
+						.content(List.of(McpSchema.TextContent.builder(message).build()))
 						.isError(true)
 						.build();
 				}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/util/ToolInputValidator.java b/mcp-core/src/main/java/io/modelcontextprotocol/util/ToolInputValidator.java
index 17a313323..76f9390a8 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/util/ToolInputValidator.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/util/ToolInputValidator.java
@@ -42,9 +42,10 @@ public static CallToolResult validate(McpSchema.Tool tool, Map<String, Object> a
 		Map<String, Object> args = arguments != null ? arguments : Map.of();
 		var validation = validator.validate(tool.inputSchema(), args);
 		if (!validation.valid()) {
-			logger.warn("Tool '{}' input validation failed: {}", tool.name(), validation.errorMessage());
+			String message = "Tool (" + tool.name() + ") input validation failed: " + validation.errorMessage();
+			logger.warn(message);
 			return CallToolResult.builder()
-				.content(List.of(McpSchema.TextContent.builder(validation.errorMessage()).build()))
+				.content(List.of(McpSchema.TextContent.builder(message).build()))
 				.isError(true)
 				.build();
 		}
diff --git a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/DefaultJsonSchemaValidator.java b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/DefaultJsonSchemaValidator.java
index d632b2d16..09bf5b5b6 100644
--- a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/DefaultJsonSchemaValidator.java
+++ b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson2/DefaultJsonSchemaValidator.java
@@ -76,8 +76,7 @@ public ValidationResponse validate(Map<String, Object> schema, Object structured
 			// Check if validation passed
 			if (!validationResult.isEmpty()) {
 				return ValidationResponse
-					.asInvalid("Validation failed: structuredContent does not match tool outputSchema. "
-							+ "Validation errors: " + validationResult);
+					.asInvalid("Validation failed: JSON schema validation errors: " + validationResult);
 			}
 
 			return ValidationResponse.asValid(jsonStructuredOutput.toString());
diff --git a/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson2/DefaultJsonSchemaValidatorTests.java b/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson2/DefaultJsonSchemaValidatorTests.java
index 3cf59aa3c..3707c0f7c 100644
--- a/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson2/DefaultJsonSchemaValidatorTests.java
+++ b/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson2/DefaultJsonSchemaValidatorTests.java
@@ -308,7 +308,7 @@ void testValidateWithInvalidTypeSchema() {
 		assertFalse(response.valid());
 		assertNotNull(response.errorMessage());
 		assertTrue(response.errorMessage().contains("Validation failed"));
-		assertTrue(response.errorMessage().contains("structuredContent does not match tool outputSchema"));
+		assertTrue(response.errorMessage().contains("JSON schema validation errors"));
 	}
 
 	@Test
diff --git a/mcp-json-jackson3/src/main/java/io/modelcontextprotocol/json/schema/jackson3/DefaultJsonSchemaValidator.java b/mcp-json-jackson3/src/main/java/io/modelcontextprotocol/json/schema/jackson3/DefaultJsonSchemaValidator.java
index 284289895..9af17ebcd 100644
--- a/mcp-json-jackson3/src/main/java/io/modelcontextprotocol/json/schema/jackson3/DefaultJsonSchemaValidator.java
+++ b/mcp-json-jackson3/src/main/java/io/modelcontextprotocol/json/schema/jackson3/DefaultJsonSchemaValidator.java
@@ -75,8 +75,7 @@ public ValidationResponse validate(Map<String, Object> schema, Object structured
 			// Check if validation passed
 			if (!validationResult.isEmpty()) {
 				return ValidationResponse
-					.asInvalid("Validation failed: structuredContent does not match tool outputSchema. "
-							+ "Validation errors: " + validationResult);
+					.asInvalid("Validation failed: JSON schema validation errors: " + validationResult);
 			}
 
 			return ValidationResponse.asValid(jsonStructuredOutput.toString());
diff --git a/mcp-json-jackson3/src/test/java/io/modelcontextprotocol/json/DefaultJsonSchemaValidatorTests.java b/mcp-json-jackson3/src/test/java/io/modelcontextprotocol/json/DefaultJsonSchemaValidatorTests.java
index be01eb23c..d56606a25 100644
--- a/mcp-json-jackson3/src/test/java/io/modelcontextprotocol/json/DefaultJsonSchemaValidatorTests.java
+++ b/mcp-json-jackson3/src/test/java/io/modelcontextprotocol/json/DefaultJsonSchemaValidatorTests.java
@@ -308,7 +308,7 @@ void testValidateWithInvalidTypeSchema() {
 		assertFalse(response.valid());
 		assertNotNull(response.errorMessage());
 		assertTrue(response.errorMessage().contains("Validation failed"));
-		assertTrue(response.errorMessage().contains("structuredContent does not match tool outputSchema"));
+		assertTrue(response.errorMessage().contains("JSON schema validation errors"));
 	}
 
 	@Test
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/server/ToolInputValidationIntegrationTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/server/ToolInputValidationIntegrationTests.java
index 5bd2a5dad..3e4f5fbd7 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/server/ToolInputValidationIntegrationTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/server/ToolInputValidationIntegrationTests.java
@@ -182,6 +182,9 @@ void invalidInput_withDefaultValidation_shouldReturnToolError(String serverType,
 
 			assertThat(result.isError()).isTrue();
 			String errorMessage = ((TextContent) result.content().get(0)).text();
+			assertThat(errorMessage).startsWith("Tool (test-tool) input validation failed:");
+			assertThat(errorMessage).containsIgnoringCase("Validation failed");
+			assertThat(errorMessage).containsIgnoringCase("JSON schema validation errors");
 			assertThat(errorMessage).containsIgnoringCase(expectedErrorSubstring);
 		}
 		finally {