Spring AI SyncMcpToolCallback call method NPE

Bug description A clear and concise description of what the bug is about. I create mcp client to invoke @modelcontextprotocol/server-filesystem by stdio. It can invoke server-filesystem success, But when SyncMcpToolCallback call method response field error is null, it will NPE.

Environment Spring AI version: 1.0.0-SNAPSHOT Java Version: 21

Steps to reproduce - application.properties config spring.application.name=mcp-examples

spring.ai.ollama.base-url=http://localhost:11434 spring.ai.ollama.chat.model=qwen2.5:latest

spring.ai.mcp.client.enabled=true spring.ai.mcp.client.name=mcp-client spring.ai.mcp.client.version=1.0.0 spring.ai.mcp.client.type=SYNC spring.ai.mcp.client.request-timeout=30s spring.ai.mcp.client.stdio.servers-configuration=classpath:/mcp-servers-config.json

• mcp-servers-config.json config { "mcpServers": { "filesystem": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/server-filesystem", "." ] } } }

• controller @RestController public class FileSystemController {

  @Resource private OllamaChatModel ollamaChatModel;

  @Resource private SyncMcpToolCallbackProvider toolCallbackProvider;

  @GetMapping("/chat") public String call(@RequestParam String input) { ChatClient chatClient = ChatClient.builder(ollamaChatModel) .defaultTools(toolCallbackProvider.getToolCallbacks()) .build(); return chatClient.prompt(input).call().content(); } }

• visit http://localhost:8080/chat?input=create folder mcp