MCP Server SDK Feature Management

The AJ-MCP annotation system provides a declarative approach to exposing Java methods as MCP (Model Context Protocol) tools, resources, and prompts. This system uses Java annotations to automatically discover and register functionality, eliminating the need for manual configuration or registration code.

Resources Development

Resources are exposed through the @Resource annotation on methods within @McpService classes. The annotation system automatically discovers and registers resources during server initialization.

The @Resource annotation exposes methods as MCP resources with the following properties:

Resource Content Types

Text Resources

Text resources return ResourceContentText objects containing plain text or structured text data.

@Resource(uri = "file:///text", description = "A nice piece of text", mimeType = "text/plain")
public ResourceContentText text() {
    ResourceContentText content = new ResourceContentText();
    content.setUri("file:///text");
    content.setMimeType("text/plain");
    content.setText("text888");
    return content;
}

Binary Resources

Binary resources return ResourceContentBinary objects containing Base64-encoded binary data.

@Resource(uri = "file:///blob", description = "A nice pic", mimeType = "image/jpg")
public ResourceContentBinary blob() {
    String base64EncodedImage = ServerUtils.encodeImageToBase64("bird-eye.jpg");

    ResourceContentBinary content = new ResourceContentBinary();
    content.setUri("file:///blob");
    content.setMimeType("image/jpg");
    content.setBlob(base64EncodedImage);

    return content;
}

Resource Templates

@ResourceTemplate methods are registered by FeatureMgr, exposed through resources/templates/list, and matched when resources/read receives a dynamic URI.

Template variables must match parameters annotated with @ResourceTemplateArg. The current matcher supports RFC 6570 Level 1 simple variables such as users://{id}.