001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.rest.server.mcp.v20250618;
018
019import org.apache.juneau.bean.mcp.v20250618.*;
020
021/**
022 * Mixin interface that exposes a {@code 2025-06-18} MCP endpoint at {@code POST /mcp} on any Juneau
023 * REST resource.
024 *
025 * <p>
026 * The mixin path and the servlet-subclass path
027 * ({@link McpRestServlet}) are at parity: both bind the revision at compile time and both
028 * expose the same {@link #capabilities()} hook.
029 *
030 * <h5 class='section'>Example:</h5>
031 * <pre>
032 * @Rest(path="/api")
033 * public class MyResource extends BasicRestServlet implements McpEndpoint {
034 *     @Override
035 *     public McpServerConfig getMcpConfig() {
036 *         return new McpServerConfig().addTool(new MyEchoTool());
037 *     }
038 * }
039 * </pre>
040 */
041public interface McpEndpoint extends org.apache.juneau.rest.server.mcp.McpEndpointMixin {
042
043   @Override /* McpEndpointMixin */
044   default McpRevision revision() {
045      return new McpRevision(capabilities());
046   }
047
048   /**
049    * Optional explicit capabilities advertisement for {@code initialize}.
050    *
051    * <p>
052    * Returning <jk>null</jk> (the default) leaves capabilities auto-derived from the registered
053    * tool / prompt / resource lists; a non-<jk>null</jk> value bypasses auto-derivation.
054    *
055    * <p>
056    * Stays a {@code default} interface method (Correction C8), for the same reason
057    * {@link McpRestServlet#capabilities()} stays {@code protected}: only {@link #revision()}
058    * above, declared on this same interface, ever calls it.
059    *
060    * @return The explicit capabilities, or <jk>null</jk> to auto-derive.
061    */
062   default ServerCapabilities capabilities() {
063      return null;
064   }
065}