Bug description I found an issue when making MCP calls, where an error occurs when the requesting controller returns Flux<> in reactive mode

java.lang.IllegalArgumentException: toolName cannot be null or empty
    at org.springframework.util.Assert.hasText(Assert.java:253) ~[spring-core-6.2.3.jar:6.2.3]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:

Environment java: oracle openJDK17 Spring AI: 1.0.0-M6 LM Studio: 0.3.12 Model: Qwen2.5

Steps to reproduce

cd spring-mcp-test
git checkout EmptyToolName
mvn clean package
java -jar mcp-server/target/mcp-server.jar
java -jar mcp-client/target/mcp-client.jar

curl http://localhost:8080/ai/mcp?message=Get%scurrent%sDate
# or message=List the files in the UV directory of drive D

Expected behavior Some information about files.

Minimal Complete Reproducible example Check out the project https://github.com/fxz26284407/spring-mcp-test

Comment From: dev-jonghoonpark

I tried running the example file you posted and it returns a message like this

What specific help do you need regarding listing files? Please provide more details.%

No errors occurred

I tested it with the gpt-4o-mini model of Open AI

Comment From: fxz26284407

I tried running the example file you posted and it returns a message like this

What specific help do you need regarding listing files? Please provide more details.%

No errors occurred

I tested it with the gpt-4o-mini model of Open AI

Sorry, the message parameter of the URL was written incorrectly. It should be like this

curl http://localhost:8080/ai/mcp?message=Get%scurrent%sDate
# or message=List the files in the UV directory of drive D

Comment From: tzolov

@fxz26284407 I've checked out your project, updated it to latest spring-ai 1.0.0-SNAPSHOT within the EmptyToolName branch I started the server and the client apps (using gpt-4o)

Then thit the http://localhost:8080/ai/mcp?message=Get%scurrent%sDate and got What specific directory would you like to list the files from?

No errors