MCP server starters SHOULD use spring.jackson properties.

Bug description
When using spring.jackson.default-property-inclusion=non_null and spring-ai-starter-mcp-server-webmvc
tool calls are returning null values.
For example "end_date": null,
I want to avoid this noise in the context window.

Expected behavior
The starter should create a ToolCallResultConverter based on the autoconfigured jackson json mapper and use it.

Workaround
Of course I can use this annotation :

@Tool(description = "Retrieve customer information", resultConverter = MyNonNullJacksonConverter.class)

But this does not fit well in the spring boot autoconfiguration philosophy.

Another solution could be to allow injecting a ToolCallResultConverter using MethodToolCallbackProvider.build().toolCallResultConverter( ... ), but this method does not exists.

My feeling is that the root problem is that DefaultToolCallResultConverter and JsonParser are not IoC friendly. Hardcoding a static JsonParser is imho a bad practice.

Start by tracing how spring-ai-starter-mcp-server-webmvc creates its ToolCallResultConverter and how DefaultToolCallResultConverter and JsonParser obtain JSON configuration. Inspect MethodToolCallbackProvider.build() and the starter autoconfiguration entry points. Done means tool-call results honor the autoconfigured spring.jackson properties, including omitting null values, without requiring a per-tool converter annotation.