Resources

Resources expose content to MCP clients by URI. You can expose static resources (one URI per method) or resource templates (a URI pattern with variables and optional completions).

Static resources

Each method annotated with @Resource is registered as a resource the client can read by that URI.

import io.github.kliushnichenko.jooby.mcp.annotation.Resource;

@Singleton
public class ResourceExamples {

    @Resource(uri = "file:///project/README.md", name = "README.md", title = "README", mimeType = "text/markdown")
    public McpSchema.TextResourceContents textResource() {
        String content = """
                # Project Title

                This is an example README file for the project.

                ## Features

                - Feature 1
                - Feature 2
                - Feature 3
                """;
        return new McpSchema.TextResourceContents("file:///project/README.md", "text/markdown", content);
    }
}

uri — Identifier clients use to request this resource.
name / title — Metadata for listing and display.
mimeType — Content type of the returned body.

Resource templates

Resource templates expose a family of resources under a URI pattern (e.g. file:///project/{name}). You implement a handler that receives the template variables and returns the content, and optionally a completion method so clients can discover or suggest valid values for a variable (e.g. project names).

import io.github.kliushnichenko.jooby.mcp.annotation.ResourceTemplate;
import io.github.kliushnichenko.jooby.mcp.annotation.CompleteResourceTemplate;
import io.github.kliushnichenko.jooby.mcp.annotation.CompleteArg;

@Singleton
public class ResourceTemplateExamples {

    private static final Map<String, String> PROJECTS = Map.of(
            "project-alpha", "This is Project Alpha.",
            "project-beta", "This is Project Beta.",
            "project-gamma", "This is Project Gamma."
    );

    @ResourceTemplate(name = "get_project", uriTemplate = "file:///project/{name}")
    public McpSchema.TextResourceContents getProject(String name, ResourceUri resourceUri) {
        String content = PROJECTS.getOrDefault(name, "<Project not found>");
        return new McpSchema.TextResourceContents(resourceUri.uri(), "text/markdown", content);
    }

    @CompleteResourceTemplate("get_project")
    public List<String> projectNameCompletion(@CompleteArg(name = "name") String partialInput) {
        return PROJECTS.keySet().stream()
                .filter(n -> n.contains(partialInput))
                .toList();
    }
}

@ResourceTemplate — Binds a handler to a URI template. Method parameters map to template variables (and ResourceUri gives the resolved URI).
@CompleteResourceTemplate — Binds a completion handler to that template. @CompleteArg maps parameters to template variables so the client can get suggestions as the user types.

Return types for resources and templates must be one of the supported resource return types. For more examples, see the example project.

Prompts Exchange Object