Crate rmcp_server_builder

Expand description

Composable MCP server builder for zero-boilerplate capability composition.

This crate provides a builder pattern for composing MCP servers from individual capability providers, eliminating the boilerplate of implementing ServerHandler and manually delegating methods.

§Overview

Instead of implementing the full ServerHandler trait and delegating methods, you can compose a server from individual providers:

use rmcp_server_builder::{Server, ServerBuilder};
use rmcp::model::Implementation;

// Compose a server with tools from one provider and prompts from another
let server = ServerBuilder::new()
    .info(Implementation::from_build_env())
    .instructions("You have access to a glTF 2.0 API...")
    .tools(openapi_server)
    .prompts(my_prompts)
    .build();

§Provider Traits

Each MCP capability has a corresponding provider trait:

ToolsProvider - list_tools, call_tool
PromptsProvider - list_prompts, get_prompt
ResourcesProvider - list_resources, list_resource_templates, read_resource, subscribe, unsubscribe
CompletionProvider - complete
LoggingProvider - set_level
ServerInfoProvider - get_info (required)

§Blanket Implementations

Any type implementing ServerHandler automatically implements all provider traits, so existing servers can be used as providers without modification.

§Capability Auto-Detection

The composed server automatically sets capability flags based on which providers are configured. If you set a tools provider, capabilities.tools will be enabled.

Structs§

Implementation
Server: A composable MCP server that routes requests to individual capability providers.
ServerBuilder: Builder for constructing a composed MCP server.
ServerCapabilities: Builder
SimpleInfo: A simple server info provider that wraps an Implementation.
Unset: Marker for an unset provider.

Traits§

CompletionProvider: Provider for completion capability.
LoggingProvider: Provider for logging capability.
PromptsProvider: Provider for prompts capability.
ResourcesProvider: Provider for resources capability.
ServerHandler
ServerInfoProvider: Provider for server info and initialization.
ToolsProvider: Provider for tools capability.