arthas mcp server default STREAMABLE protocol (#3114)

Author: Yeaury

arthas-mcp-server/src/main/java/com/taobao/arthas/mcp/server/protocol/config/McpServerProperties.java

@@ -193,7 +193,7 @@ public static class Builder {
         private Duration requestTimeout = Duration.ofSeconds(10);
         private Duration initializationTimeout = Duration.ofSeconds(30);
         private ObjectMapper objectMapper;
-        private ServerProtocol protocol = ServerProtocol.STATELESS;
+        private ServerProtocol protocol = ServerProtocol.STREAMABLE;
 
         public Builder() {
             // Private constructor to prevent direct instantiation

arthas-mcp-server/src/main/java/com/taobao/arthas/mcp/server/protocol/server/handler/McpHttpRequestHandler.java

@@ -193,7 +193,7 @@ public McpHttpRequestHandler build() {
             Assert.notNull(this.mcpEndpoint, "MCP endpoint must be set");
 
             if (this.protocol == null) {
-                this.protocol = ServerProtocol.STATELESS;
+                this.protocol = ServerProtocol.STREAMABLE;
             }
 
             McpHttpRequestHandler handler = new McpHttpRequestHandler(this.mcpEndpoint, this.objectMapper, this.contextExtractor);

core/src/main/java/com/taobao/arthas/core/mcp/ArthasMcpServer.java

@@ -59,12 +59,12 @@ public ArthasMcpServer(String mcpEndpoint, CommandExecutor commandExecutor, Stri
         this.mcpEndpoint = mcpEndpoint != null ? mcpEndpoint : DEFAULT_MCP_ENDPOINT;
         this.commandExecutor = commandExecutor;
 
-        ServerProtocol resolvedProtocol = ServerProtocol.STATELESS;
+        ServerProtocol resolvedProtocol = ServerProtocol.STREAMABLE;
         if (protocol != null && !protocol.trim().isEmpty()) {
             try {
                 resolvedProtocol = ServerProtocol.valueOf(protocol.toUpperCase());
             } catch (IllegalArgumentException e) {
-                logger.warn("Invalid MCP protocol: {}. Using default: STATELESS", protocol);
+                logger.warn("Invalid MCP protocol: {}. Using default: STREAMABLE", protocol);
             }
         }
         this.protocol = resolvedProtocol;