build: validate duplicate MCP tool names before packaging

dap-tool-core/src/main/java/io/shinhanlife/dap/lib/validation/McpToolNameValidationRunner.java

@@ -0,0 +1,21 @@
+package io.shinhanlife.dap.lib.validation;
+
+import java.nio.file.Path;
+
+/** Gradle entry point for validating unique MCP Tool names before packaging. */
+public final class McpToolNameValidationRunner {
+
+    private McpToolNameValidationRunner() {
+    }
+
+    public static void main(String[] args) {
+        if (args.length != 1) {
+            throw new IllegalArgumentException("Usage: McpToolNameValidationRunner <project-root>");
+        }
+        validate(Path.of(args[0]));
+    }
+
+    static void validate(Path projectRoot) {
+        McpToolNameValidator.assertUnique(projectRoot);
+    }
+}

dap-tool-core/src/test/java/io/shinhanlife/dap/lib/validation/McpToolNameValidatorTest.java

@@ -42,6 +42,15 @@ class McpToolNameValidatorTest {
         assertTrue(exception.getMessage().contains("dap-tool-second"));
     }
 
+    @Test
+    void validationRunnerRejectsDuplicateMcpFunctionNamesBeforePackaging() throws IOException {
+        writeToolSource("dap-tool-first", "FirstTool.java", "first", "send_sms");
+        writeToolSource("dap-tool-second", "SecondTool.java", "second", "send_sms");
+
+        assertThrows(IllegalStateException.class,
+                () -> McpToolNameValidationRunner.validate(temporaryRoot));
+    }
+
     @Test
     void acceptsCurrentProjectToolNames() {
         assertDoesNotThrow(() -> McpToolNameValidator.assertUnique(findProjectRoot()));