Add mcp-server module: order-lookup service exposed via @McpTool/@McpResource/@McpPrompt over Streamable HTTP

Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01FtpJvZfg4nvLvtzgJTDWpB
2026-09-23 11:56:37 +00:00
parent c1fc41e0de
commit 9919da58a7
21 changed files with 704 additions and 0 deletions
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+package com.ankurm.mcpserver;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class McpServerApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(McpServerApplication.class, args);
+	}
+
+}
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+package com.ankurm.mcpserver.domain;
+
+import java.math.BigDecimal;
+import java.util.List;
+
+/**
+ * The existing domain type this module pretends predates MCP entirely -- the point of this
+ * article is exposing a service that already looks like this, not designing one around MCP.
+ */
+public record Order(String id, String customer, OrderStatus status, List<String> items, BigDecimal total) {
+}
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+package com.ankurm.mcpserver.domain;
+
+import java.math.BigDecimal;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import org.springframework.stereotype.Repository;
+
+/**
+ * Stand-in for a real order-lookup service (a JPA repository, a call to another microservice,
+ * whatever it actually is at your shop). The MCP-facing code in {@code tools} never needs to
+ * change if this gets replaced with the real thing -- it depends on this interface's shape, not
+ * its storage.
+ */
+@Repository
+public class OrderRepository {
+
+	private final Map<String, Order> orders = new LinkedHashMap<>();
+
+	public OrderRepository() {
+		orders.put("ORD-1001", new Order("ORD-1001", "Priya Nair", OrderStatus.SHIPPED,
+				List.of("Mechanical keyboard", "USB-C cable"), new BigDecimal("4899.00")));
+		orders.put("ORD-1002", new Order("ORD-1002", "Rohan Mehta", OrderStatus.PENDING,
+				List.of("27\" monitor"), new BigDecimal("18999.00")));
+		orders.put("ORD-1003", new Order("ORD-1003", "Ankita Rao", OrderStatus.DELIVERED,
+				List.of("Laptop stand", "Wireless mouse", "USB hub"), new BigDecimal("3450.00")));
+		orders.put("ORD-1004", new Order("ORD-1004", "Vikram Shah", OrderStatus.CANCELLED,
+				List.of("Graphics card"), new BigDecimal("42999.00")));
+	}
+
+	public Optional<Order> findById(String id) {
+		return Optional.ofNullable(orders.get(id));
+	}
+
+	public List<Order> findAll() {
+		return List.copyOf(orders.values());
+	}
+
+}
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+package com.ankurm.mcpserver.domain;
+
+public enum OrderStatus {
+	PENDING, SHIPPED, DELIVERED, CANCELLED
+}
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+package com.ankurm.mcpserver.tools;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.springframework.ai.mcp.annotation.McpArg;
+import org.springframework.ai.mcp.annotation.McpPrompt;
+import org.springframework.ai.mcp.annotation.McpResource;
+import org.springframework.ai.mcp.annotation.McpTool;
+import org.springframework.ai.mcp.annotation.McpToolParam;
+import org.springframework.stereotype.Service;
+
+import com.ankurm.mcpserver.domain.Order;
+import com.ankurm.mcpserver.domain.OrderRepository;
+
+/**
+ * The existing service this article exposes over MCP. Nothing here imports an MCP class except
+ * the three annotations -- {@link OrderRepository} and {@link Order} are ordinary Spring beans
+ * and domain types that would exist whether or not an AI agent ever called them.
+ */
+@Service
+public class OrderTools {
+
+	private final OrderRepository repository;
+
+	public OrderTools(OrderRepository repository) {
+		this.repository = repository;
+	}
+
+	@McpTool(name = "lookup_order", description = "Look up a single order by its ID and return its customer, status, items, and total.")
+	public Order lookupOrder(
+			@McpToolParam(description = "The order ID, e.g. ORD-1001", required = true) String orderId) {
+		return repository.findById(orderId)
+				.orElseThrow(() -> new IllegalArgumentException("No order with ID " + orderId));
+	}
+
+	@McpResource(uri = "orders://catalog", name = "order-catalog",
+			description = "Every order ID currently in the system, one per line -- read this first if you don't already have an order ID to look up.",
+			mimeType = "text/plain")
+	public String orderCatalog() {
+		return repository.findAll().stream().map(Order::id).collect(Collectors.joining("\n"));
+	}
+
+	@McpPrompt(name = "summarize_order", description = "A ready-made prompt asking a model to write a one-paragraph customer-support summary of one order.")
+	public String summarizeOrderPrompt(
+			@McpArg(name = "orderId", description = "The order ID to summarize, e.g. ORD-1001", required = true) String orderId) {
+		return "Call the lookup_order tool for order " + orderId
+				+ ", then write a single short paragraph a customer support agent could paste into a reply: "
+				+ "state the order status in plain language, list the items, and mention the total. "
+				+ "Do not invent any detail the tool did not return.";
+	}
+
+}
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+spring:
+  application:
+    name: mcp-server
+  ai:
+    mcp:
+      server:
+        name: order-lookup-server
+        version: 1.0.0
+        # The jar's own spring-configuration-metadata.json lists "streamable" as this
+        # property's default -- but that is only the @ConfigurationProperties field default,
+        # and the autoconfiguration class that actually wires the /mcp endpoint is gated by
+        # @ConditionalOnProperty, which only ever looks at the Environment, never at a field
+        # default. Leave this property unset and McpServerStreamableHttpWebMvcAutoConfiguration
+        # never matches, full stop -- see the article for the real condition-evaluation log line.
+        protocol: streamable