feat: Add _meta to tool/prompt/resource declaration

[vdm24]

Append the ability to define "_meta" property in tool, prompt, resource declarations

Usage:

@McpTool(metaProvider = MyMetaProvider.class)
String myTool() {
}

class MyMetaProvider implements MetaProvider {

    @Override
    public Map<String, Object> getMeta() {
        return Map.of(
            "openai/widgetPrefersBorder", true,
            "openai/widgetDomain", "https://chatgpt.com",
            "openai/widgetCSP", new WidgetCsp());
    }
}

Issue: #81

[vdm24]

Hi @tzolov
what do you think about this concept? Is it okay in general? If you have a better idea, I can try to implement it.

[vdm24]

Hi everyone,

is this "community" project alive?

It has been nearly three weeks since the PR was opened, but there hasn’t been any reaction from maintainers - no comments, no reviews, no even an emoji. This lack of activity seems weird for a Spring project...

[valery1707]

It has been nearly three weeks since the PR was opened, but there hasn’t been any reaction from maintainers - no comments, no reviews, no even an emoji. This lack of activity seems weird for a Spring project...

I have PR spring-projects/spring-ai#3666 with almost half year of inactivity ... but with some reaction, but only after about 3 months ...

[embesozzi]

In version 1.1.2, it supports defining at least some annotations.

   annotations = @McpTool.McpAnnotations(
                    title = "",
                    readOnlyHint = true,
                    destructiveHint = false,
                    idempotentHint = true
            )

[scottslewis]

For all information:

There are active discussions around moving the MCP - specified annotation types in this package to the mcp-java-sdk

modelcontextprotocol/java-sdk#491

and

#10

this would likely mean a new package in the mcp-java-sdk package namespace (e.g.io.modelcontextprotocol.annotation or io.modelcontextprotocol.spec.annotation, etc).

A main reason for such a move of annotation classes from mcp-annotation to mcp-java-sdk is that the annotations are completely specified by the MCP protocol spec...which defines the specific meta-data that the tooling can provide...e.g. @mcptool fields correspond to the specification schema of Tool properties....i.e. description, title, name, annotation

If there is consensus in this and the mcp-java-sdk projects around a move/refactor of annotation classes from mcp-annotations to new io.modelcontextprotocol.annotation package, I will produce a pull request to the mcp-java-sdk project that adds all the annotation types currently defined in mcp-annotations.

If there is consensus around the solution provided above (MetaProvider) it could be added as part of this refactor.