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Provides Model Context Protocol (MCP) server implementation patterns with Spring AI. Use when building MCP servers to extend AI capabilities with custom tools, resources, and prompt templates using Spring's official AI framework.
npx skill4agent add giuseppe-trisciuoglio/developer-kit-claude-code spring-ai-mcp-server-patterns@Tool@PromptTemplatepom.xmlbuild.gradleapplication.properties@EnableMcpServer@Component@Tool(description = "...")@ToolParam@PromptTemplate@PromptParamPromptstdiohttpsseapplication.yml@SpringBootApplication
@EnableMcpServer
public class WeatherMcpApplication {
public static void main(String[] args) {
SpringApplication.run(WeatherMcpApplication.class, args);
}
}
@Component
public class WeatherTools {
@Tool(description = "Get current weather for a city")
public WeatherData getWeather(@ToolParam("City name") String city) {
// Implementation
return new WeatherData(city, "Sunny", 22.5);
}
}application.propertiesspring.ai.openai.api-key=${OPENAI_API_KEY}
spring.ai.mcp.enabled=true
spring.ai.mcp.transport=stdio<dependency>
<groupId>org.springframework.ai</groupId>
<artifactId>spring-ai-mcp-server</artifactId>
<version>1.0.0</version>
</dependency>
<dependency>
<groupId>org.springframework.ai</groupId>
<artifactId>spring-ai-starter-model-openai</artifactId>
<version>1.0.0</version>
</dependency>dependencies {
implementation 'org.springframework.ai:spring-ai-mcp-server:1.0.0'
implementation 'org.springframework.ai:spring-ai-starter-model-openai:1.0.0'
}<dependency>
<groupId>org.springframework.ai</groupId>
<artifactId>spring-ai-mcp-starter</artifactId>
<version>1.0.0</version>
</dependency>@Tool@PromptTemplateAI Application ←→ MCP Client ←→ Spring AI ←→ MCP Server ←→ Spring Services@Component
public class DatabaseTools {
private final JdbcTemplate jdbcTemplate;
public DatabaseTools(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
@Tool(description = "Execute a safe read-only SQL query")
public List<Map<String, Object>> executeQuery(
@ToolParam("SQL SELECT query") String query,
@ToolParam(value = "Query parameters", required = false)
Map<String, Object> params) {
// Validate query is read-only
if (!query.trim().toUpperCase().startsWith("SELECT")) {
throw new IllegalArgumentException("Only SELECT queries are allowed");
}
return jdbcTemplate.queryForList(query, params);
}
@Tool(description = "Get table schema information")
public TableSchema getTableSchema(
@ToolParam("Table name") String tableName) {
String sql = "SELECT column_name, data_type " +
"FROM information_schema.columns " +
"WHERE table_name = ?";
List<Map<String, Object>> columns = jdbcTemplate.queryForList(sql, tableName);
return new TableSchema(tableName, columns);
}
}
record TableSchema(String tableName, List<Map<String, Object>> columns) {}@Component
public class ApiTools {
private final WebClient webClient;
public ApiTools(WebClient.Builder webClientBuilder) {
this.webClient = webClientBuilder.build();
}
@Tool(description = "Make HTTP GET request to an API")
public ApiResponse callApi(
@ToolParam("API URL") String url,
@ToolParam(value = "Headers as JSON string", required = false)
String headersJson) {
// Validate URL
try {
new URL(url);
} catch (MalformedURLException e) {
throw new IllegalArgumentException("Invalid URL format");
}
// Parse headers if provided
HttpHeaders headers = new HttpHeaders();
if (headersJson != null && !headersJson.isBlank()) {
try {
Map<String, String> headersMap = new ObjectMapper()
.readValue(headersJson, Map.class);
headersMap.forEach(headers::add);
} catch (JsonProcessingException e) {
throw new IllegalArgumentException("Invalid headers JSON");
}
}
return webClient.get()
.uri(url)
.headers(h -> h.addAll(headers))
.retrieve()
.bodyToMono(ApiResponse.class)
.block();
}
}
record ApiResponse(int status, Map<String, Object> body, HttpHeaders headers) {}@Component
public class CodeReviewPrompts {
@PromptTemplate(
name = "java-code-review",
description = "Review Java code for best practices and issues"
)
public Prompt createJavaCodeReviewPrompt(
@PromptParam("code") String code,
@PromptParam(value = "focusAreas", required = false)
List<String> focusAreas) {
String focus = focusAreas != null ?
String.join(", ", focusAreas) :
"general best practices";
return Prompt.builder()
.system("You are an expert Java code reviewer with 20 years of experience.")
.user("""
Review the following Java code for {focus}:
```java
{code}
```
Provide feedback in the following format:
1. Critical issues (must fix)
2. Warnings (should fix)
3. Suggestions (consider improving)
4. Positive aspects
Be specific and provide code examples where relevant.
""".replace("{code}", code).replace("{focus}", focus))
.build();
}
@PromptTemplate(
name = "generate-unit-tests",
description = "Generate comprehensive unit tests for Java code"
)
public Prompt createTestGenerationPrompt(
@PromptParam("code") String code,
@PromptParam("className") String className,
@PromptParam(value = "testingFramework", required = false)
String framework) {
String testFramework = framework != null ? framework : "JUnit 5";
return Prompt.builder()
.system("You are an expert in test-driven development.")
.user("""
Generate comprehensive unit tests for the following Java class using {testFramework}:
```java
{code}
```
Class: {className}
Requirements:
1. Test all public methods
2. Include edge cases and boundary conditions
3. Use appropriate assertions
4. Follow AAA pattern (Arrange, Act, Assert)
5. Include test method naming best practices
6. Mock external dependencies
""".replace("{code}", code)
.replace("{className}", className)
.replace("{testFramework}", testFramework))
.build();
}
}@Configuration
public class FunctionConfig {
@Bean
public FunctionCallback weatherFunction() {
return FunctionCallback.builder()
.function("getCurrentWeather", new WeatherService())
.description("Get the current weather for a location")
.inputType(WeatherRequest.class)
.build();
}
@Bean
public FunctionCallback calculatorFunction() {
return FunctionCallbackWrapper.builder(new Calculator())
.withName("calculate")
.withDescription("Perform mathematical calculations")
.build();
}
}
class WeatherService implements Function<WeatherRequest, WeatherResponse> {
@Override
public WeatherResponse apply(WeatherRequest request) {
// Call weather API
return new WeatherResponse(request.location(), 72, "Sunny");
}
}
record WeatherRequest(String location) {}
record WeatherResponse(String location, double temperature, String condition) {}
class Calculator implements BiFunction<String, Map<String, Object>, String> {
@Override
public String apply(String functionName, Map<String, Object> args) {
// Perform calculation based on args
return "result";
}
}@Configuration
@AutoConfigureAfter({WebMvcAutoConfiguration.class})
@ConditionalOnClass({McpServer.class, ChatModel.class})
@ConditionalOnProperty(name = "spring.ai.mcp.enabled", havingValue = "true", matchIfMissing = true)
public class McpAutoConfiguration {
@Bean
@ConditionalOnMissingBean
public McpServerProperties mcpServerProperties() {
return new McpServerProperties();
}
@Bean
@ConditionalOnMissingBean
public McpServer mcpServer(
List<FunctionCallback> functionCallbacks,
List<PromptTemplate> promptTemplates,
McpServerProperties properties
) {
McpServer.Builder builder = McpServer.builder()
.serverInfo("spring-ai-mcp", "1.0.0")
.transport(properties.getTransport().create());
// Register function callbacks as tools
functionCallbacks.forEach(callback ->
builder.tool(Tool.fromFunctionCallback(callback))
);
// Register prompt templates
promptTemplates.forEach(template ->
builder.prompt(Prompt.fromTemplate(template))
);
return builder.build();
}
@Bean
@ConditionalOnProperty(name = "spring.ai.mcp.actuator.enabled", havingValue = "true")
public McpHealthIndicator mcpHealthIndicator(McpServer mcpServer) {
return new McpHealthIndicator(mcpServer);
}
}
@ConfigurationProperties(prefix = "spring.ai.mcp")
public class McpServerProperties {
private boolean enabled = true;
private TransportConfig transport = new TransportConfig();
private ActuatorConfig actuator = new ActuatorConfig();
// Getters and setters
public static class TransportConfig {
private TransportType type = TransportType.STDIO;
private HttpConfig http = new HttpConfig();
public Transport create() {
return switch (type) {
case STDIO -> new StdioTransport();
case HTTP -> new HttpTransport(http.getPort());
case SSE -> new SseTransport(http.getPort(), http.getPath());
};
}
}
public static class HttpConfig {
private int port = 8080;
private String path = "/mcp";
// Getters and setters
}
public static class ActuatorConfig {
private boolean enabled = true;
// Getters and setters
}
public enum TransportType {
STDIO, HTTP, SSE
}
}application.ymlspring:
ai:
mcp:
enabled: true
transport:
type: stdio # Options: stdio, http, sse
http:
port: 8080
path: /mcp
actuator:
enabled: true
tools:
package-scan: com.example.tools
prompts:
package-scan: com.example.prompts
security:
enabled: true
allowed-tools:
- getWeather
- executeQuery
admin-tools:
- admin_*@Configuration
public class CustomMcpConfig {
@Bean
public McpServerCustomizer mcpServerCustomizer() {
return server -> {
server.addToolInterceptor((tool, args, chain) -> {
log.info("Executing tool: {}", tool.name());
long start = System.currentTimeMillis();
Object result = chain.execute(tool, args);
long duration = System.currentTimeMillis() - start;
log.info("Tool {} executed in {}ms", tool.name(), duration);
metrics.recordToolExecution(tool.name(), duration);
return result;
});
};
}
@Bean
public ToolFilter toolFilter(SecurityService securityService) {
return (tool, context) -> {
User user = securityService.getCurrentUser();
if (tool.name().startsWith("admin_")) {
return user.hasRole("ADMIN");
}
return securityService.isToolAllowed(user, tool.name());
};
}
}
@Service
public class SecurityService {
public boolean isToolAllowed(User user, String toolName) {
// Implement tool access control logic
return true;
}
}@Component
public class SecureToolExecutor {
private final McpServer mcpServer;
private final SecurityContextHolder strategy;
public SecureToolExecutor(McpServer mcpServer, SecurityContextHolder strategy) {
this.mcpServer = mcpServer;
this.strategy = strategy;
}
public ToolResult executeTool(String toolName, Map<String, Object> arguments) {
Authentication auth = SecurityContextHolder.getContext().getAuthentication();
if (!(auth instanceof UserAuthentication userAuth)) {
throw new AccessDeniedException("User not authenticated");
}
// Check tool permissions
if (!hasToolPermission(userAuth.getUser(), toolName)) {
throw new AccessDeniedException("Tool not allowed: " + toolName);
}
// Validate arguments against injection patterns
validateArguments(arguments);
// Execute with audit logging
logToolExecution(userAuth.getUser(), toolName, arguments);
try {
ToolResult result = mcpServer.executeTool(toolName, arguments);
logToolSuccess(userAuth.getUser(), toolName);
return result;
} catch (Exception e) {
logToolFailure(userAuth.getUser(), toolName, e);
throw new ToolExecutionException("Tool execution failed", e);
}
}
private boolean hasToolPermission(User user, String toolName) {
// Implement permission logic based on user roles and tool sensitivity
return user.getAuthorities().stream()
.anyMatch(auth -> auth.getAuthority().equals("TOOL_" + toolName) ||
auth.getAuthority().equals("ROLE_ADMIN"));
}
private void validateArguments(Map<String, Object> arguments) {
// Implement argument validation to prevent injection attacks
arguments.forEach((key, value) -> {
if (value instanceof String str) {
if (str.contains(";") || str.contains("--")) {
throw new IllegalArgumentException("Invalid characters in argument: " + key);
}
}
});
}
private void logToolExecution(User user, String toolName, Map<String, Object> arguments) {
// Implement audit logging
}
private void logToolSuccess(User user, String toolName) {
// Log successful execution
}
private void logToolFailure(User user, String toolName, Exception e) {
// Log failed execution
}
}
class ToolExecutionException extends RuntimeException {
public ToolExecutionException(String message, Throwable cause) {
super(message, cause);
}
}@Component
public class ValidatedTools {
@Tool(description = "Process user data with validation")
@Validated
public ProcessingResult processUserData(
@ToolParam("User data to process") @Valid UserData data) {
// Implementation
return new ProcessingResult("success", data);
}
}
record UserData(
@NotBlank(message = "Name is required")
@Size(max = 100, message = "Name must be 100 characters or less")
String name,
@NotNull(message = "Age is required")
@Min(value = 18, message = "Must be 18 or older")
@Max(value = 120, message = "Age must be realistic")
Integer age,
@NotBlank(message = "Email is required")
@Email(message = "Invalid email format")
String email
) {}
// Custom validator for sensitive operations
@Component
public class SensitiveOperationValidator {
public void validateOperation(String operation, User user, Map<String, Object> params) {
if (isSensitiveOperation(operation)) {
requireAdditionalAuthentication(user);
validateOperationLimits(user, operation);
logSensitiveOperation(user, operation, params);
}
}
private boolean isSensitiveOperation(String operation) {
return operation.startsWith("delete") || operation.startsWith("update");
}
private void requireAdditionalAuthentication(User user) {
// Implement MFA or re-authentication
}
private void validateOperationLimits(User user, String operation) {
// Check rate limits and quotas
}
private void logSensitiveOperation(User user, String operation, Map<String, Object> params) {
// Secure audit logging
}
}@ControllerAdvice
public class McpExceptionHandler {
@ExceptionHandler(ToolExecutionException.class)
public ResponseEntity<ErrorResponse> handleToolExecutionException(
ToolExecutionException ex, WebRequest request) {
ErrorResponse error = ErrorResponse.builder()
.timestamp(LocalDateTime.now())
.status(HttpStatus.INTERNAL_SERVER_ERROR.value())
.error("Tool Execution Failed")
.message(ex.getMessage())
.path(((ServletWebRequest) request).getRequest().getRequestURI())
.build();
log.error("Tool execution failed: {}", ex.getMessage(), ex);
return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
}
@ExceptionHandler(AccessDeniedException.class)
public ResponseEntity<ErrorResponse> handleAccessDenied(
AccessDeniedException ex, WebRequest request) {
ErrorResponse error = ErrorResponse.builder()
.timestamp(LocalDateTime.now())
.status(HttpStatus.FORBIDDEN.value())
.error("Access Denied")
.message("You do not have permission to execute this tool")
.path(((ServletWebRequest) request).getRequest().getRequestURI())
.build();
log.warn("Access denied: {}", ex.getMessage());
return new ResponseEntity<>(error, HttpStatus.FORBIDDEN);
}
@ExceptionHandler(IllegalArgumentException.class)
public ResponseEntity<ErrorResponse> handleValidationError(
IllegalArgumentException ex, WebRequest request) {
ErrorResponse error = ErrorResponse.builder()
.timestamp(LocalDateTime.now())
.status(HttpStatus.BAD_REQUEST.value())
.error("Validation Error")
.message(ex.getMessage())
.path(((ServletWebRequest) request).getRequest().getRequestURI())
.build();
return new ResponseEntity<>(error, HttpStatus.BAD_REQUEST);
}
@ExceptionHandler(Exception.class)
public ResponseEntity<ErrorResponse> handleGenericException(
Exception ex, WebRequest request) {
ErrorResponse error = ErrorResponse.builder()
.timestamp(LocalDateTime.now())
.status(HttpStatus.INTERNAL_SERVER_ERROR.value())
.error("Internal Server Error")
.message("An unexpected error occurred")
.path(((ServletWebRequest) request).getRequest().getRequestURI())
.build();
log.error("Unexpected error: {}", ex.getMessage(), ex);
return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
}
@Data
@Builder
static class ErrorResponse {
private LocalDateTime timestamp;
private int status;
private String error;
private String message;
private String path;
}
}public class DynamicToolRegistry {
private final McpServer mcpServer;
private final Map<String, ToolRegistration> registeredTools = new ConcurrentHashMap<>();
public DynamicToolRegistry(McpServer mcpServer) {
this.mcpServer = mcpServer;
}
public void registerTool(ToolRegistration registration) {
registeredTools.put(registration.getId(), registration);
Tool tool = Tool.builder()
.name(registration.getName())
.description(registration.getDescription())
.inputSchema(registration.getInputSchema())
.function(args -> executeDynamicTool(registration.getId(), args))
.build();
mcpServer.addTool(tool);
log.info("Registered dynamic tool: {}", registration.getName());
}
public void unregisterTool(String toolId) {
ToolRegistration registration = registeredTools.remove(toolId);
if (registration != null) {
mcpServer.removeTool(registration.getName());
log.info("Unregistered dynamic tool: {}", registration.getName());
}
}
private Object executeDynamicTool(String toolId, Map<String, Object> args) {
ToolRegistration registration = registeredTools.get(toolId);
if (registration == null) {
throw new IllegalStateException("Tool not found: " + toolId);
}
// Execute based on registration type
return switch (registration.getType()) {
case GROOVY_SCRIPT -> executeGroovyScript(registration, args);
case SPRING_BEAN -> executeSpringBeanMethod(registration, args);
case HTTP_ENDPOINT -> callHttpEndpoint(registration, args);
};
}
private Object executeGroovyScript(ToolRegistration registration, Map<String, Object> args) {
// Implement Groovy script execution
return null;
}
private Object executeSpringBeanMethod(ToolRegistration registration, Map<String, Object> args) {
// Implement Spring bean method invocation
return null;
}
private Object callHttpEndpoint(ToolRegistration registration, Map<String, Object> args) {
// Implement HTTP call
return null;
}
}
@Data
@Builder
class ToolRegistration {
private String id;
private String name;
private String description;
private Map<String, Object> inputSchema;
private ToolType type;
private String target; // script, bean name, or URL
private Map<String, String> metadata;
}
enum ToolType {
GROOVY_SCRIPT,
SPRING_BEAN,
HTTP_ENDPOINT
}@Configuration
public class MultiModelConfig {
@Bean
@Primary
public ChatModel primaryChatModel(@Value("${spring.ai.primary.model}") String modelName) {
return switch (modelName) {
case "gpt-4" -> new OpenAiChatModel(OpenAiApi.builder()
.apiKey(System.getenv("OPENAI_API_KEY"))
.build());
case "claude" -> new AnthropicChatModel(AnthropicApi.builder()
.apiKey(System.getenv("ANTHROPIC_API_KEY"))
.build());
default -> throw new IllegalArgumentException("Unsupported model: " + modelName);
};
}
@Bean
public Map<String, ChatModel> allChatModels() {
Map<String, ChatModel> models = new HashMap<>();
models.put("gpt-4", new OpenAiChatModel(OpenAiApi.builder()
.apiKey(System.getenv("OPENAI_API_KEY"))
.build()));
models.put("gpt-3.5", new OpenAiChatModel(OpenAiApi.builder()
.apiKey(System.getenv("OPENAI_API_KEY"))
.model("gpt-3.5-turbo")
.build()));
models.put("claude-opus", new AnthropicChatModel(AnthropicApi.builder()
.apiKey(System.getenv("ANTHROPIC_API_KEY"))
.model("claude-3-opus-20240229")
.build()));
return models;
}
@Bean
public ModelSelector modelSelector(Map<String, ChatModel> models) {
return new SpringAiModelSelector(models);
}
}
@Component
public class SpringAiModelSelector implements ModelSelector {
private final Map<String, ChatModel> models;
public SpringAiModelSelector(Map<String, ChatModel> models) {
this.models = models;
}
@Override
public ChatModel selectModel(Prompt prompt, Map<String, Object> context) {
// Select model based on prompt complexity, cost, latency requirements
String modelName = determineBestModel(prompt, context);
return models.get(modelName);
}
private String determineBestModel(Prompt prompt, Map<String, Object> context) {
// Implement model selection logic
// Consider: prompt length, complexity, cost constraints, latency requirements
return "gpt-4";
}
}@Configuration
@EnableCaching
public class McpCacheConfig {
@Bean
public CacheManager cacheManager() {
return new ConcurrentMapCacheManager(
"tool-results",
"prompt-templates",
"function-callbacks"
);
}
}
@Component
public class CachedToolExecutor {
private final McpServer mcpServer;
public CachedToolExecutor(McpServer mcpServer) {
this.mcpServer = mcpServer;
}
@Cacheable(
value = "tool-results",
key = "#toolName + '_' + #args.hashCode()",
unless = "#result.isCacheable() == false"
)
public ToolResult executeTool(String toolName, Map<String, Object> args) {
return mcpServer.executeTool(toolName, args);
}
@CacheEvict(value = "tool-results", allEntries = true)
public void clearToolCache() {
// Clear cache when tools are updated
}
@Cacheable(value = "prompt-templates", key = "#templateName")
public PromptTemplate getPromptTemplate(String templateName) {
return mcpServer.getPromptTemplate(templateName);
}
}@SpringBootTest
class DatabaseToolsTest {
@Autowired
private DatabaseTools databaseTools;
@MockBean
private JdbcTemplate jdbcTemplate;
@Test
void testExecuteQuery_Success() {
// Given
String query = "SELECT * FROM users WHERE id = ?";
Map<String, Object> params = Map.of("id", 1);
List<Map<String, Object>> expectedResults = List.of(
Map.of("id", 1, "name", "John")
);
when(jdbcTemplate.queryForList(anyString(), anyMap()))
.thenReturn(expectedResults);
// When
List<Map<String, Object>> results = databaseTools.executeQuery(query, params);
// Then
assertThat(results).isEqualTo(expectedResults);
verify(jdbcTemplate).queryForList(query, params);
}
@Test
void testExecuteQuery_InvalidQuery_ThrowsException() {
// Given
String query = "DROP TABLE users";
// When & Then
assertThatThrownBy(() -> databaseTools.executeQuery(query, null))
.isInstanceOf(IllegalArgumentException.class)
.hasMessage("Only SELECT queries are allowed");
verifyNoInteractions(jdbcTemplate);
}
@Test
void testGetTableSchema_Success() {
// Given
String tableName = "users";
List<Map<String, Object>> columns = List.of(
Map.of("column_name", "id", "data_type", "integer"),
Map.of("column_name", "name", "data_type", "varchar")
);
when(jdbcTemplate.queryForList(anyString(), eq(tableName)))
.thenReturn(columns);
// When
TableSchema schema = databaseTools.getTableSchema(tableName);
// Then
assertThat(schema.tableName()).isEqualTo(tableName);
assertThat(schema.columns()).isEqualTo(columns);
}
}@SpringBootTest
@AutoConfigureMockMvc
class McpServerIntegrationTest {
@Autowired
private MockMvc mockMvc;
@Autowired
private McpServer mcpServer;
@MockBean
private DatabaseTools databaseTools;
@Test
void testExecuteTool_Success() throws Exception {
// Given
String toolName = "executeQuery";
Map<String, Object> args = Map.of(
"query", "SELECT * FROM users",
"params", Map.of()
);
List<Map<String, Object>> expectedResult = List.of(
Map.of("id", 1, "name", "Test User")
);
when(databaseTools.executeQuery(anyString(), anyMap()))
.thenReturn(expectedResult);
// When & Then
mockMvc.perform(post("/mcp/tools/executeQuery")
.contentType(MediaType.APPLICATION_JSON)
.content(new ObjectMapper().writeValueAsString(args)))
.andExpect(status().isOk())
.andExpect(jsonPath("$.result").isArray())
.andExpect(jsonPath("$.result[0].id").value(1));
}
@Test
void testListTools_Success() throws Exception {
// When & Then
mockMvc.perform(get("/mcp/tools"))
.andExpect(status().isOk())
.andExpect(jsonPath("$.tools").isArray());
}
@Test
void testHealthEndpoint() throws Exception {
// When & Then
mockMvc.perform(get("/actuator/health/mcp"))
.andExpect(status().isOk())
.andExpect(jsonPath("$.status").value("UP"));
}
}@SpringBootTest
@Testcontainers
@AutoConfigureMockMvc
class McpServerIntegrationTest {
@Container
static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:15")
.withDatabaseName("testdb")
.withUsername("test")
.withPassword("test");
@DynamicPropertySource
static void properties(DynamicPropertyRegistry registry) {
registry.add("spring.datasource.url", postgres::getJdbcUrl);
registry.add("spring.datasource.username", postgres::getUsername);
registry.add("spring.datasource.password", postgres::getPassword);
}
@Autowired
private MockMvc mockMvc;
@Test
void testDatabaseToolWithRealDatabase() throws Exception {
// Given
String query = "SELECT current_database(), current_user";
Map<String, Object> request = Map.of(
"tool", "executeQuery",
"arguments", Map.of("query", query)
);
// When & Then
mockMvc.perform(post("/mcp/tools/executeQuery")
.contentType(MediaType.APPLICATION_JSON)
.content(new ObjectMapper().writeValueAsString(request)))
.andExpect(status().isOk())
.andExpect(jsonPath("$.success").value(true))
.andExpect(jsonPath("$.data[0].current_database").value("testdb"))
.andExpect(jsonPath("$.data[0].current_user").value("test"));
}
}@WebMvcTest(controllers = McpController.class)
class McpControllerSliceTest {
@Autowired
private MockMvc mockMvc;
@MockBean
private McpServer mcpServer;
@MockBean
private ToolRegistry toolRegistry;
@Test
void testListToolsEndpoint() throws Exception {
// Given
Tool tool1 = Tool.builder().name("tool1").description("Tool 1").build();
Tool tool2 = Tool.builder().name("tool2").description("Tool 2").build();
when(toolRegistry.listTools()).thenReturn(List.of(tool1, tool2));
// When & Then
mockMvc.perform(get("/mcp/tools"))
.andExpect(status().isOk())
.andExpect(jsonPath("$.tools").isArray())
.andExpect(jsonPath("$.tools.length()").value(2))
.andExpect(jsonPath("$.tools[0].name").value("tool1"));
}
}@ExtendWith(MockitoExtension.class)
class ToolValidationTest {
private ToolValidator validator;
@BeforeEach
void setUp() {
McpServerProperties properties = new McpServerProperties();
properties.getTools().getValidation().setMaxArgumentsSize(1000);
validator = new DefaultToolValidator(properties);
}
@Test
void testValidArguments() {
// Given
Tool tool = Tool.builder()
.name("testTool")
.method(getTestMethod())
.build();
Map<String, Object> args = Map.of("param1", "value1", "param2", 123);
// When & Then
assertDoesNotThrow(() -> validator.validateArguments(tool, args));
}
@Test
void testArgumentsTooLarge() {
// Given
Tool tool = Tool.builder().name("testTool").build();
Map<String, Object> args = Map.of("largeParam", "x".repeat(2000));
// When & Then
ValidationException exception = assertThrows(
ValidationException.class,
() -> validator.validateArguments(tool, args)
);
assertThat(exception.getMessage()).contains("Arguments too large");
}
}@SpringBootTest
@AutoConfigureMockMvc
@WithMockUser(roles = {"USER"})
class McpSecurityTest {
@Autowired
private MockMvc mockMvc;
@Test
void testUserCanAccessRegularTools() throws Exception {
mockMvc.perform(get("/mcp/tools/getWeather"))
.andExpect(status().isOk());
}
@Test
@WithMockUser(roles = {"USER"})
void testUserCannotAccessAdminTools() throws Exception {
mockMvc.perform(get("/mcp/tools/admin/deleteData"))
.andExpect(status().isForbidden());
}
@Test
@WithMockUser(roles = {"ADMIN"})
void testAdminCanAccessAllTools() throws Exception {
mockMvc.perform(get("/mcp/tools/admin/deleteData"))
.andExpect(status().isOk());
}
}@SpringBootTest
@EnableConfigurationProperties(McpServerProperties.class)
class McpPropertiesTest {
@Autowired
private McpServerProperties properties;
@Test
void testDefaultValues() {
assertThat(properties.getServer().getName()).isEqualTo("spring-ai-mcp-server");
assertThat(properties.getTransport().getType()).isEqualTo(TransportType.STDIO);
assertThat(properties.getSecurity().isEnabled()).isFalse();
}
}# Spring AI Configuration
spring.ai.openai.api-key=${OPENAI_API_KEY}
spring.ai.openai.chat.options.model=gpt-4o-mini
spring.ai.openai.chat.options.temperature=0.7
# MCP Server Configuration
spring.ai.mcp.enabled=true
spring.ai.mcp.server.name=spring-ai-mcp-server
spring.ai.mcp.server.version=1.0.0
spring.ai.mcp.transport.type=stdio
# HTTP Transport (if enabled)
spring.ai.mcp.transport.http.port=8080
spring.ai.mcp.transport.http.path=/mcp
spring.ai.mcp.transport.http.cors.enabled=true
spring.ai.mcp.transport.http.cors.allowed-origins=*
# Security Configuration
spring.ai.mcp.security.enabled=true
spring.ai.mcp.security.authorization.mode=role-based
spring.ai.mcp.security.authorization.default-deny=true
spring.ai.mcp.security.audit.enabled=true
# Tool Configuration
spring.ai.mcp.tools.package-scan=com.example.mcp.tools
spring.ai.mcp.tools.validation.enabled=true
spring.ai.mcp.tools.validation.max-execution-time=30s
spring.ai.mcp.tools.caching.enabled=true
spring.ai.mcp.tools.caching.ttl=5m
# Prompt Configuration
spring.ai.mcp.prompts.package-scan=com.example.mcp.prompts
spring.ai.mcp.prompts.caching.enabled=true
spring.ai.mcp.prompts.caching.ttl=1h
# Actuator and Monitoring
spring.ai.mcp.actuator.enabled=true
spring.ai.mcp.metrics.enabled=true
spring.ai.mcp.metrics.export.prometheus.enabled=true
spring.ai.mcp.logging.enabled=true
spring.ai.mcp.logging.level=DEBUG
# Performance Tuning
spring.ai.mcp.thread-pool.core-size=10
spring.ai.mcp.thread-pool.max-size=50
spring.ai.mcp.thread-pool.queue-capacity=100
spring.ai.mcp.rate-limiter.enabled=true
spring.ai.mcp.rate-limiter.requests-per-minute=100@Tool@PromptTemplategetcreateupdatedeletesearch@ToolParam@PreAuthorize@Cacheable@Asyncapplication.yml@ConfigurationProperties@Qualifier@Tool@ToolMethodFunctionCallback@ToolMethod@Toolapplication.properties@Component// Before: LangChain4j
@ToolMethod("Get weather information")
public String getWeather(@P("city name") String city) {
return weatherService.getWeather(city);
}
// After: Spring AI
@Component
public class WeatherTools {
@Tool(description = "Get weather information")
public String getWeather(@ToolParam("City name") String city) {
return weatherService.getWeather(city);
}
}// Application.java
@SpringBootApplication
@EnableMcpServer
public class WeatherMcpServerApplication {
public static void main(String[] args) {
SpringApplication.run(WeatherMcpServerApplication.class, args);
}
}
// WeatherTools.java
@Component
@Slf4j
public class WeatherTools {
private final WeatherService weatherService;
private final MeterRegistry meterRegistry;
public WeatherTools(WeatherService weatherService, MeterRegistry meterRegistry) {
this.weatherService = weatherService;
this.meterRegistry = meterRegistry;
}
@Tool(description = "Get current weather conditions for a city")
public WeatherResponse getCurrentWeather(
@ToolParam("City name (e.g., 'New York, NY')") String city) {
Timer.Sample sample = Timer.start(meterRegistry);
try {
log.info("Fetching weather for: {}", city);
WeatherResponse response = weatherService.getCurrentWeather(city);
sample.stop(Timer.builder("weather.tool.duration")
.tag("city", city)
.register(meterRegistry));
return response;
} catch (Exception e) {
log.error("Error fetching weather for {}", city, e);
throw new ToolExecutionException("Unable to fetch weather data", e);
}
}
@Tool(description = "Get 5-day weather forecast for a city")
public ForecastResponse getForecast(
@ToolParam("City name") String city,
@ToolParam(value = "Temperature unit (celsius or fahrenheit)", required = false)
String unit) {
String tempUnit = unit != null ? unit : "celsius";
return weatherService.getForecast(city, tempUnit);
}
@Tool(description = "Get weather alerts for a location")
public List<WeatherAlert> getWeatherAlerts(
@ToolParam("State or province code (e.g., 'CA', 'NY')") String stateCode) {
return weatherService.getAlerts(stateCode);
}
}
// WeatherService.java
@Service
public class WeatherService {
private final WebClient webClient;
private final WeatherCache cache;
public WeatherService(WebClient.Builder webClientBuilder,
WeatherCache cache) {
this.webClient = webClientBuilder
.baseUrl("https://api.weather.gov")
.build();
this.cache = cache;
}
@Cacheable(value = "weather", key = "#city")
public WeatherResponse getCurrentWeather(String city) {
return webClient.get()
.uri("/points/{city}/forecast", city)
.retrieve()
.bodyToMono(WeatherResponse.class)
.block();
}
}@Component
@PreAuthorize("hasRole('USER')")
public class DatabaseTools {
private final JdbcTemplate jdbcTemplate;
private final QueryValidator validator;
public DatabaseTools(JdbcTemplate jdbcTemplate, QueryValidator validator) {
this.jdbcTemplate = jdbcTemplate;
this.validator = validator;
}
@Tool(description = "Execute a read-only SQL query and return results")
public QueryResult executeQuery(
@ToolParam("SQL SELECT query to execute") String sql,
@ToolParam(value = "Query parameters as JSON map", required = false)
String paramsJson) {
// Validate query is read-only
validator.validateReadOnly(sql);
// Parse parameters
Map<String, Object> params = parseParams(paramsJson);
// Execute with timeout
return jdbcTemplate.query(sql, params, rs -> {
ResultSetMetaData metaData = rs.getMetaData();
int columnCount = metaData.getColumnCount();
List<Map<String, Object>> rows = new ArrayList<>();
while (rs.next()) {
Map<String, Object> row = new LinkedHashMap<>();
for (int i = 1; i <= columnCount; i++) {
row.put(metaData.getColumnName(i), rs.getObject(i));
}
rows.add(row);
}
return new QueryResult(rows, rows.size());
});
}
@Tool(description = "Get table metadata including columns and types")
public TableMetadata describeTable(
@ToolParam("Table name") String tableName) {
String sql = """
SELECT column_name, data_type, is_nullable, column_default
FROM information_schema.columns
WHERE table_name = ?
ORDER BY ordinal_position
""";
List<ColumnInfo> columns = jdbcTemplate.query(sql,
(rs, rowNum) -> new ColumnInfo(
rs.getString("column_name"),
rs.getString("data_type"),
rs.getString("is_nullable").equals("YES"),
rs.getString("column_default")
),
tableName
);
return new TableMetadata(tableName, columns);
}
}@Component
@Slf4j
public class FileSystemTools {
private final Path basePath;
private final FileSecurityFilter securityFilter;
public FileSystemTools(
@Value("${mcp.file.base-path:/tmp}") String basePath,
FileSecurityFilter securityFilter) {
this.basePath = Paths.get(basePath).normalize();
this.securityFilter = securityFilter;
}
@Tool(description = "List files in a directory")
public List<FileInfo> listFiles(
@ToolParam(value = "Directory path (relative to base)", required = false)
String directory) {
Path targetPath = resolvePath(directory != null ? directory : "");
securityFilter.validatePath(targetPath, basePath);
try (Stream<Path> stream = Files.list(targetPath)) {
return stream
.filter(Files::isRegularFile)
.map(this::toFileInfo)
.toList();
} catch (IOException e) {
throw new ToolExecutionException("Failed to list files", e);
}
}
@Tool(description = "Read file contents")
public FileContent readFile(
@ToolParam("File path (relative to base)") String filePath,
@ToolParam(value = "Maximum lines to read", required = false)
Integer maxLines) {
Path targetPath = resolvePath(filePath);
securityFilter.validatePath(targetPath, basePath);
try {
List<String> lines = maxLines != null
? Files.lines(targetPath).limit(maxLines).toList()
: Files.readAllLines(targetPath);
return new FileContent(targetPath.toString(), lines);
} catch (IOException e) {
throw new ToolExecutionException("Failed to read file", e);
}
}
@Tool(description = "Search for files matching a pattern")
public List<FileInfo> searchFiles(
@ToolParam("Search pattern (glob, e.g., '*.txt')") String pattern,
@ToolParam(value = "Directory to search in", required = false)
String directory) {
Path targetPath = resolvePath(directory != null ? directory : "");
securityFilter.validatePath(targetPath, basePath);
try (Stream<Path> stream = Files.walk(targetPath, 10)) {
PathMatcher matcher = FileSystems.getDefault()
.getPathMatcher("glob:" + pattern);
return stream
.filter(Files::isRegularFile)
.filter(path -> matcher.matches(path.getFileName()))
.map(this::toFileInfo)
.toList();
} catch (IOException e) {
throw new ToolExecutionException("Search failed", e);
}
}
private Path resolvePath(String relativePath) {
return basePath.resolve(relativePath).normalize();
}
private FileInfo toFileInfo(Path path) {
try {
return new FileInfo(
basePath.relativize(path).toString(),
Files.size(path),
Files.getLastModifiedTime(path).toInstant()
);
} catch (IOException e) {
return new FileInfo(path.toString(), 0, Instant.now());
}
}
}@Component
@Slf4j
public class ApiIntegrationTools {
private final WebClient webClient;
private final ApiCredentialManager credentialManager;
public ApiIntegrationTools(WebClient.Builder webClientBuilder,
ApiCredentialManager credentialManager) {
this.webClient = webClientBuilder.build();
this.credentialManager = credentialManager;
}
@Tool(description = "Call an external REST API endpoint")
public ApiResponse callExternalApi(
@ToolParam("HTTP method (GET, POST, PUT, DELETE)") String method,
@ToolParam("API URL") String url,
@ToolParam(value = "Request body (JSON)", required = false)
String body,
@ToolParam(value = "Headers (JSON map)", required = false)
String headersJson) {
// Validate URL
validateUrl(url);
// Get credentials
ApiCredentials credentials = credentialManager.getCredentials(url);
// Build request
WebClient.RequestBodySpec request = webClient
.method(HttpMethod.valueOf(method.toUpperCase()))
.uri(url);
// Add headers
addHeaders(request, headersJson, credentials);
// Add body if applicable
if (body != null && !body.isBlank()) {
request.contentType(MediaType.APPLICATION_JSON);
request.body(body);
}
// Execute
return request.retrieve()
.bodyToMono(ApiResponse.class)
.block();
}
@Tool(description = "Paginate through API results")
public List<ApiResponse> fetchPaginatedResults(
@ToolParam("Base API URL") String baseUrl,
@ToolParam(value = "Page size", required = false)
Integer pageSize) {
int size = pageSize != null ? pageSize : 100;
List<ApiResponse> allResults = new ArrayList<>();
int page = 0;
while (true) {
String url = baseUrl + "?page=" + page + "&size=" + size;
PaginatedResponse response = webClient.get()
.uri(url)
.retrieve()
.bodyToMono(PaginatedResponse.class)
.block();
allResults.addAll(response.getData());
if (!response.hasNext()) {
break;
}
page++;
}
return allResults;
}
}@Component
public class CodeReviewPrompts {
@PromptTemplate(
name = "java-code-review",
description = "Review Java code for best practices and potential issues"
)
public Prompt createCodeReviewPrompt(
@PromptParam("Java code to review") String code,
@PromptParam(value = "Focus areas (comma-separated)", required = false)
String focusAreas) {
String focus = focusAreas != null ? focusAreas : "general best practices";
return Prompt.builder()
.system(createSystemPrompt())
.user(createUserPrompt(code, focus))
.build();
}
@PromptTemplate(
name = "refactor-suggestion",
description = "Suggest refactoring improvements for code"
)
public Prompt createRefactorPrompt(
@PromptParam("Code to refactor") String code,
@PromptParam("Refactoring goal") String goal) {
return Prompt.builder()
.system("You are an expert software architect specializing in code refactoring.")
.user("""
Analyze the following code and suggest refactoring to achieve: {goal}
```java
{code}
```
Provide:
1. Current issues identified
2. Suggested refactoring approach
3. Refactored code example
4. Benefits of the refactoring
""".replace("{code}", code).replace("{goal}", goal))
.build();
}
private String createSystemPrompt() {
return """
You are an expert Java code reviewer with 20 years of experience.
Focus on:
- Code correctness and potential bugs
- Performance optimizations
- Security vulnerabilities
- SOLID principles adherence
- Clean code practices
- Design pattern usage
""";
}
private String createUserPrompt(String code, String focus) {
return """
Review the following Java code with focus on: {focus}
```java
{code}
```
Format your response as:
## Critical Issues (Must Fix)
## Warnings (Should Fix)
## Suggestions (Consider Improving)
## Positive Aspects
""".replace("{code}", code).replace("{focus}", focus);
}
}# application.yml
spring:
application:
name: weather-mcp-server
ai:
openai:
api-key: ${OPENAI_API_KEY}
chat:
options:
model: gpt-4o-mini
temperature: 0.7
mcp:
enabled: true
server:
name: weather-mcp-server
version: 1.0.0
transport:
type: stdio # or http, sse
http:
port: 8080
path: /mcp
cors:
enabled: true
allowed-origins: "*"
security:
enabled: true
authorization:
mode: role-based
default-deny: true
audit:
enabled: true
tools:
package-scan: com.example.mcp.tools
validation:
enabled: true
max-execution-time: 30s
caching:
enabled: true
ttl: 5m
actuator:
enabled: true
management:
endpoints:
web:
exposure:
include: health,info,metrics,prometheus
endpoint:
health:
show-details: always
metrics:
export:
prometheus:
enabled: true
logging:
level:
com.example.mcp: DEBUG
org.springframework.ai: INFO../../etc/passwd