why does mcp tools say that the value is null when it is provided

[jbrinnand]

Here is how I am using mcptools to access my springboot mcp-server:

Tool is:
@Tool(name = "searchPeopleByName", description = "Search for people by name") public List<Person> searchPeopleByName(String name) {

mcp call searchPeopleByName --params '{"name":"John"}' java -jar ./target/springboot-mcp-server-1.0-SNAPSHOT.jar

Here is what mcptools returns:
Cannot invoke "String.toLowerCase()" because "name" is null

The same goes for getting a person by ID
@Tool(name = "getPersonById", description = "Find a person by their ID") public Person getPersonById(Long id) {

mcp call getPersonById --params '{"id": 1}' java -jar ./target/springboot-mcp-server-1.0-SNAPSHOT.jar

Here is the response:
Cannot invoke "Object.hashCode()" because "key" is null

When I test this code using springboot-mcp-client, all these methods work as specified. However, I want the capability of testing mcp-servers using stdio on the CLI. I was hoping your tool would help. However, other than the most simple commands that take no params, all it says is that the key is null.

Any help would be appreciated.

[jbrinnand]

I listed all the tools and realized that the tools were being listed with arg0, arg1 as the method arguments instead of the Java types String, Long, etc.

For example the listing the tools:

mcp tools java -jar ./target/springboot-mcp-server-1.0-SNAPSHOT.jar                                                                     
deletePerson(arg0:int)
    Delete a person by their ID

getPersonById(arg0:int)
    Find a person by their ID

getAllPeople
    Get all people in the system

searchPeopleByName(arg0:str)
    Search for people by name

createPerson(arg0:str, arg1:str, arg2:str, arg3:str)
    Create a new person

updatePerson(arg0:int, [arg1:str], [arg2:str], [arg3:str], [arg4:str])
    Update an existing person

So - if the call is changed to:
mcp call getPersonById --params '{"arg0":1}' java -jar ./target/springboot-mcp-server-1.0-SNAPSHOT.jar | jq .

The response is:

{
  "id": 1,
  "name": "John Doe",
  "email": "john.doe@example.com",
  "phone": "123-456-7890",
  "nationality": "USA"
}

So - it works. Thanks!