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# RMCP
[](https://crates.io/crates/rmcp)
[](https://docs.rs/rmcp/latest/rmcp)
[](https://github.com/modelcontextprotocol/rust-sdk/actions/workflows/ci.yml)
[](LICENSE)
An official Rust Model Context Protocol SDK implementation with tokio async runtime.
> **Migrating to 1.x?** See the [migration guide](https://github.com/modelcontextprotocol/rust-sdk/discussions/716) for breaking changes and upgrade instructions.
This repository contains the following crates:
- [rmcp](crates/rmcp): The core crate providing the RMCP protocol implementation - see [rmcp](crates/rmcp/README.md)
- [rmcp-macros](crates/rmcp-macros): A procedural macro crate for generating RMCP tool implementations - see [rmcp-macros](crates/rmcp-macros/README.md)
For the full MCP specification, see [modelcontextprotocol.io](https://modelcontextprotocol.io/specification/2025-11-25).
## Table of Contents
- [Usage](#usage)
- [Tools](#tools)
- [Resources](#resources)
- [Prompts](#prompts)
- [Sampling](#sampling)
- [Roots](#roots)
- [Logging](#logging)
- [Completions](#completions)
- [Notifications](#notifications)
- [Subscriptions](#subscriptions)
- [Tasks](#tasks-long-running-tool-invocations)
- [Examples](#examples)
- [OAuth Support](#oauth-support)
- [Related Resources](#related-resources)
- [Related Projects](#related-projects)
- [Development](#development)
## Usage
### Import the crate
```toml
rmcp = { version = "0.16.0", features = ["server"] }
## or dev channel
rmcp = { git = "https://github.com/modelcontextprotocol/rust-sdk", branch = "main" }
```
### Third Dependencies
Basic dependencies:
- [tokio](https://github.com/tokio-rs/tokio)
- [serde](https://github.com/serde-rs/serde)
Json Schema generation (version 2020-12):
- [schemars](https://github.com/GREsau/schemars)
### Build a Client
<details>
<summary>Start a client</summary>
```rust, ignore
use rmcp::{ServiceExt, transport::{TokioChildProcess, ConfigureCommandExt}};
use tokio::process::Command;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let client = ().serve(TokioChildProcess::new(Command::new("npx").configure(|cmd| {
cmd.arg("-y").arg("@modelcontextprotocol/server-everything");
}))?).await?;
Ok(())
}
```
</details>
### Build a Server
<details>
<summary>Build a transport</summary>
```rust, ignore
use tokio::io::{stdin, stdout};
let transport = (stdin(), stdout());
```
</details>
<details>
<summary>Build a service</summary>
You can easily build a service by using [`ServerHandler`](crates/rmcp/src/handler/server.rs) or [`ClientHandler`](crates/rmcp/src/handler/client.rs).
```rust, ignore
let service = common::counter::Counter::new();
```
</details>
<details>
<summary>Start the server</summary>
```rust, ignore
// this call will finish the initialization process
let server = service.serve(transport).await?;
```
</details>
<details>
<summary>Interact with the server</summary>
Once the server is initialized, you can send requests or notifications:
```rust, ignore
// request
let roots = server.list_roots().await?;
// or send notification
server.notify_cancelled(...).await?;
```
</details>
<details>
<summary>Waiting for service shutdown</summary>
```rust, ignore
let quit_reason = server.waiting().await?;
// or cancel it
let quit_reason = server.cancel().await?;
```
</details>
---
## Tools
Tools let servers expose callable functions to clients. Each tool has a name, description, and a JSON Schema for its parameters. Clients discover tools via `list_tools` and invoke them via `call_tool`.
**MCP Spec:** [Tools](https://modelcontextprotocol.io/specification/2025-11-25/server/tools)
### Server-side
The `#[tool]`, `#[tool_router]`, and `#[tool_handler]` macros handle all the wiring. For a tools-only server you can use `#[tool_router(server_handler)]` to skip the separate `ServerHandler` impl:
```rust,ignore
use rmcp::{handler::server::wrapper::Parameters, schemars, tool, tool_router, ServiceExt, transport::stdio};
#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
struct AddParams {
a: i32,
b: i32,
}
#[derive(Clone)]
struct Calculator;
#[tool_router(server_handler)]
impl Calculator {
#[tool(description = "Add two numbers")]
fn add(&self, Parameters(AddParams { a, b }): Parameters<AddParams>) -> String {
(a + b).to_string()
}
}
#[tokio::main]
async fn main() -> anyhow::Result<()> {
let service = Calculator.serve(stdio()).await?;
service.waiting().await?;
Ok(())
}
```
When you need custom server metadata or multiple capabilities (tools + prompts), use explicit `#[tool_handler]`:
```rust,ignore
use rmcp::{handler::server::wrapper::Parameters, schemars, tool, tool_router, tool_handler, ServerHandler, ServiceExt};
#[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
struct AddParams {
a: i32,
b: i32,
}
#[derive(Clone)]
struct Calculator;
#[tool_router]
impl Calculator {
#[tool(description = "Add two numbers")]
fn add(&self, Parameters(AddParams { a, b }): Parameters<AddParams>) -> String {
(a + b).to_string()
}
}
#[tool_handler(name = "calculator", version = "1.0.0", instructions = "A simple calculator")]
impl ServerHandler for Calculator {}
```
See [`crates/rmcp-macros`](crates/rmcp-macros/README.md) for full macro documentation.
### Client-side
```rust,ignore
use rmcp::model::CallToolRequestParams;
// List all tools
let tools = client.list_all_tools().await?;
// Call a tool by name
let result = client.call_tool(CallToolRequestParams::new("add")).await?;
```
**Example:** [`examples/servers/src/common/calculator.rs`](examples/servers/src/common/calculator.rs) (server), [`examples/servers/src/calculator_stdio.rs`](examples/servers/src/calculator_stdio.rs) (stdio runner)
---
## Resources
Resources let servers expose data (files, database records, API responses) that clients can read. Each resource is identified by a URI and returns content as text or binary (base64-encoded) data. Resource templates allow servers to declare URI patterns with dynamic parameters.
**MCP Spec:** [Resources](https://modelcontextprotocol.io/specification/2025-11-25/server/resources)
### Server-side
Implement `list_resources()`, `read_resource()`, and optionally `list_resource_templates()` on the `ServerHandler` trait. Enable the resources capability in `get_info()`.
```rust
use rmcp::{
ErrorData as McpError, RoleServer, ServerHandler, ServiceExt,
model::*,
service::RequestContext,
transport::stdio,
};
use serde_json::json;
#[derive(Clone)]
struct MyServer;
impl ServerHandler for MyServer {
fn get_info(&self) -> ServerInfo {
ServerInfo {
capabilities: ServerCapabilities::builder()
.enable_resources()
.build(),
..Default::default()
}
}
async fn list_resources(
&self,
_request: Option<PaginatedRequestParams>,
_context: RequestContext<RoleServer>,
) -> Result<ListResourcesResult, McpError> {
Ok(ListResourcesResult {
resources: vec![
RawResource::new("file:///config.json", "config").no_annotation(),
RawResource::new("memo://insights", "insights").no_annotation(),
],
next_cursor: None,
meta: None,
})
}
async fn read_resource(
&self,
request: ReadResourceRequestParams,
_context: RequestContext<RoleServer>,
) -> Result<ReadResourceResult, McpError> {
match request.uri.as_str() {
"file:///config.json" => Ok(ReadResourceResult {
contents: vec![ResourceContents::text(r#"{"key": "value"}"#, &request.uri)],
}),
"memo://insights" => Ok(ReadResourceResult {
contents: vec![ResourceContents::text("Analysis results...", &request.uri)],
}),
_ => Err(McpError::resource_not_found(
"resource_not_found",
Some(json!({ "uri": request.uri })),
)),
}
}
async fn list_resource_templates(
&self,
_request: Option<PaginatedRequestParams>,
_context: RequestContext<RoleServer>,
) -> Result<ListResourceTemplatesResult, McpError> {
Ok(ListResourceTemplatesResult {
resource_templates: vec![],
next_cursor: None,
meta: None,
})
}
}
```
### Client-side
```rust
use rmcp::model::{ReadResourceRequestParams};
// List all resources (handles pagination automatically)
let resources = client.list_all_resources().await?;
// Read a specific resource by URI
let result = client.read_resource(ReadResourceRequestParams {
meta: None,
uri: "file:///config.json".into(),
}).await?;
// List resource templates
let templates = client.list_all_resource_templates().await?;
```
### Notifications
Servers can notify clients when the resource list changes or when a specific resource is updated:
```rust
// Notify that the resource list has changed (clients should re-fetch)
context.peer.notify_resource_list_changed().await?;
// Notify that a specific resource was updated
context.peer.notify_resource_updated(ResourceUpdatedNotificationParam {
uri: "file:///config.json".into(),
}).await?;
```
Clients handle these via `ClientHandler`:
```rust
impl ClientHandler for MyClient {
async fn on_resource_list_changed(
&self,
_context: NotificationContext<RoleClient>,
) {
// Re-fetch the resource list
}
async fn on_resource_updated(
&self,
params: ResourceUpdatedNotificationParam,
_context: NotificationContext<RoleClient>,
) {
// Re-read the updated resource at params.uri
}
}
```
**Example:** [`examples/servers/src/common/counter.rs`](examples/servers/src/common/counter.rs) (server), [`examples/clients/src/everything_stdio.rs`](examples/clients/src/everything_stdio.rs) (client)
---
## Prompts
Prompts are reusable message templates that servers expose to clients. They accept typed arguments and return conversation messages. The `#[prompt]` macro handles argument validation and routing automatically.
**MCP Spec:** [Prompts](https://modelcontextprotocol.io/specification/2025-11-25/server/prompts)
### Server-side
Use the `#[prompt_router]`, `#[prompt]`, and `#[prompt_handler]` macros to define prompts declaratively. Arguments are defined as structs deriving `JsonSchema`.
```rust
use rmcp::{
ErrorData as McpError, RoleServer, ServerHandler, ServiceExt,
handler::server::{router::prompt::PromptRouter, wrapper::Parameters},
model::*,
prompt, prompt_handler, prompt_router,
schemars::JsonSchema,
service::RequestContext,
transport::stdio,
};
use serde::{Deserialize, Serialize};
#[derive(Debug, Serialize, Deserialize, JsonSchema)]
pub struct CodeReviewArgs {
#[schemars(description = "Programming language of the code")]
pub language: String,
#[schemars(description = "Focus areas for the review")]
pub focus_areas: Option<Vec<String>>,
}
#[derive(Clone)]
pub struct MyServer {
prompt_router: PromptRouter<Self>,
}
#[prompt_router]
impl MyServer {
fn new() -> Self {
Self { prompt_router: Self::prompt_router() }
}
/// Simple prompt without parameters
#[prompt(name = "greeting", description = "A simple greeting")]
async fn greeting(&self) -> Vec<PromptMessage> {
vec![PromptMessage::new_text(
PromptMessageRole::User,
"Hello! How can you help me today?",
)]
}
/// Prompt with typed arguments
#[prompt(name = "code_review", description = "Review code in a given language")]
async fn code_review(
&self,
Parameters(args): Parameters<CodeReviewArgs>,
) -> Result<GetPromptResult, McpError> {
let focus = args.focus_areas
.unwrap_or_else(|| vec!["correctness".into()]);
Ok(GetPromptResult {
description: Some(format!("Code review for {}", args.language)),
messages: vec![
PromptMessage::new_text(
PromptMessageRole::User,
format!("Review my {} code. Focus on: {}", args.language, focus.join(", ")),
),
],
})
}
}
#[prompt_handler]
impl ServerHandler for MyServer {
fn get_info(&self) -> ServerInfo {
ServerInfo {
capabilities: ServerCapabilities::builder().enable_prompts().build(),
..Default::default()
}
}
}
```
Prompt functions support several return types:
- `Vec<PromptMessage>` -- simple message list
- `GetPromptResult` -- messages with an optional description
- `Result<T, McpError>` -- either of the above, with error handling
### Client-side
```rust
use rmcp::model::GetPromptRequestParams;
// List all prompts
let prompts = client.list_all_prompts().await?;
// Get a prompt with arguments
let result = client.get_prompt(GetPromptRequestParams {
meta: None,
name: "code_review".into(),
arguments: Some(rmcp::object!({
"language": "Rust",
"focus_areas": ["performance", "safety"]
})),
}).await?;
```
### Notifications
```rust
// Server: notify that available prompts have changed
context.peer.notify_prompt_list_changed().await?;
```
**Example:** [`examples/servers/src/prompt_stdio.rs`](examples/servers/src/prompt_stdio.rs) (server), [`examples/clients/src/everything_stdio.rs`](examples/clients/src/everything_stdio.rs) (client)
---
## Sampling
Sampling flips the usual direction: the server asks the client to run an LLM completion. The server sends a `create_message` request, the client processes it through its LLM, and returns the result.
**MCP Spec:** [Sampling](https://modelcontextprotocol.io/specification/2025-11-25/client/sampling)
### Server-side (requesting sampling)
Access the client's sampling capability through `context.peer.create_message()`:
```rust
use rmcp::model::*;
// Inside a ServerHandler method (e.g., call_tool):
let response = context.peer.create_message(CreateMessageRequestParams {
meta: None,
task: None,
messages: vec![SamplingMessage::user_text("Explain this error: connection refused")],
model_preferences: Some(ModelPreferences {
hints: Some(vec![ModelHint { name: Some("claude".into()) }]),
cost_priority: Some(0.3),
speed_priority: Some(0.8),
intelligence_priority: Some(0.7),
}),
system_prompt: Some("You are a helpful assistant.".into()),
include_context: Some(ContextInclusion::None),
temperature: Some(0.7),
max_tokens: 150,
stop_sequences: None,
metadata: None,
tools: None,
tool_choice: None,
}).await?;
// Extract the response text
let text = response.message.content
.first()
.and_then(|c| c.as_text())
.map(|t| &t.text);
```
### Client-side (handling sampling)
On the client side, implement `ClientHandler::create_message()`. This is where you'd call your actual LLM:
```rust
use rmcp::{ClientHandler, model::*, service::{RequestContext, RoleClient}};
#[derive(Clone, Default)]
struct MyClient;
impl ClientHandler for MyClient {
async fn create_message(
&self,
params: CreateMessageRequestParams,
_context: RequestContext<RoleClient>,
) -> Result<CreateMessageResult, ErrorData> {
// Forward to your LLM, or return a mock response:
let response_text = call_your_llm(¶ms.messages).await;
Ok(CreateMessageResult {
message: SamplingMessage::assistant_text(response_text),
model: "my-model".into(),
stop_reason: Some(CreateMessageResult::STOP_REASON_END_TURN.into()),
})
}
}
```
**Example:** [`examples/servers/src/sampling_stdio.rs`](examples/servers/src/sampling_stdio.rs) (server), [`examples/clients/src/sampling_stdio.rs`](examples/clients/src/sampling_stdio.rs) (client)
---
## Roots
Roots tell servers which directories or projects the client is working in. A root is a URI (typically `file://`) pointing to a workspace or repository. Servers can query roots to know where to look for files and how to scope their work.
**MCP Spec:** [Roots](https://modelcontextprotocol.io/specification/2025-11-25/client/roots)
### Server-side
Ask the client for its root list, and handle change notifications:
```rust
use rmcp::{ServerHandler, model::*, service::{NotificationContext, RoleServer}};
impl ServerHandler for MyServer {
// Query the client for its roots
async fn call_tool(
&self,
request: CallToolRequestParams,
context: RequestContext<RoleServer>,
) -> Result<CallToolResult, ErrorData> {
let roots = context.peer.list_roots().await?;
// Use roots.roots to understand workspace boundaries
// ...
}
// Called when the client's root list changes
async fn on_roots_list_changed(
&self,
_context: NotificationContext<RoleServer>,
) {
// Re-fetch roots to stay current
}
}
```
### Client-side
Clients declare roots capability and implement `list_roots()`:
```rust
use rmcp::{ClientHandler, model::*};
impl ClientHandler for MyClient {
async fn list_roots(
&self,
_context: RequestContext<RoleClient>,
) -> Result<ListRootsResult, ErrorData> {
Ok(ListRootsResult {
roots: vec![
Root {
uri: "file:///home/user/project".into(),
name: Some("My Project".into()),
},
],
})
}
}
```
Clients notify the server when roots change:
```rust
// After adding or removing a workspace root:
client.notify_roots_list_changed().await?;
```
---
## Logging
Servers can send structured log messages to clients. The client sets a minimum severity level, and the server sends messages through the peer notification interface.
**MCP Spec:** [Logging](https://modelcontextprotocol.io/specification/2025-11-25/server/utilities/logging)
### Server-side
Enable the logging capability, handle level changes from the client, and send log messages via the peer:
```rust
use rmcp::{ServerHandler, model::*, service::RequestContext};
impl ServerHandler for MyServer {
fn get_info(&self) -> ServerInfo {
ServerInfo {
capabilities: ServerCapabilities::builder()
.enable_logging()
.build(),
..Default::default()
}
}
// Client sets the minimum log level
async fn set_level(
&self,
request: SetLevelRequestParams,
_context: RequestContext<RoleServer>,
) -> Result<(), ErrorData> {
// Store request.level and filter future log messages accordingly
Ok(())
}
}
// Send a log message from any handler with access to the peer:
context.peer.notify_logging_message(LoggingMessageNotificationParam {
level: LoggingLevel::Info,
logger: Some("my-server".into()),
data: serde_json::json!({
"message": "Processing completed",
"items_processed": 42
}),
}).await?;
```
Available log levels (from least to most severe): `Debug`, `Info`, `Notice`, `Warning`, `Error`, `Critical`, `Alert`, `Emergency`.
### Client-side
Clients handle incoming log messages via `ClientHandler`:
```rust
impl ClientHandler for MyClient {
async fn on_logging_message(
&self,
params: LoggingMessageNotificationParam,
_context: NotificationContext<RoleClient>,
) {
println!("[{}] {}: {}", params.level,
params.logger.unwrap_or_default(), params.data);
}
}
```
Clients can also set the server's log level:
```rust
client.set_level(SetLevelRequestParams {
level: LoggingLevel::Warning,
meta: None,
}).await?;
```
---
## Completions
Completions give auto-completion suggestions for prompt or resource template arguments. As a user fills in arguments, the client can ask the server for suggestions based on what's already been entered.
**MCP Spec:** [Completions](https://modelcontextprotocol.io/specification/2025-11-25/server/utilities/completion)
### Server-side
Enable the completions capability and implement the `complete()` handler. Use `request.context` to inspect previously filled arguments:
```rust
use rmcp::{ErrorData as McpError, ServerHandler, model::*, service::RequestContext, RoleServer};
impl ServerHandler for MyServer {
fn get_info(&self) -> ServerInfo {
ServerInfo {
capabilities: ServerCapabilities::builder()
.enable_completions()
.enable_prompts()
.build(),
..Default::default()
}
}
async fn complete(
&self,
request: CompleteRequestParams,
_context: RequestContext<RoleServer>,
) -> Result<CompleteResult, McpError> {
let values = match &request.r#ref {
Reference::Prompt(prompt_ref) if prompt_ref.name == "sql_query" => {
match request.argument.name.as_str() {
"operation" => vec!["SELECT", "INSERT", "UPDATE", "DELETE"],
"table" => vec!["users", "orders", "products"],
"columns" => {
// Adapt suggestions based on previously filled arguments
if let Some(ctx) = &request.context {
if let Some(op) = ctx.get_argument("operation") {
match op.to_uppercase().as_str() {
"SELECT" | "UPDATE" => {
vec!["id", "name", "email", "created_at"]
}
_ => vec![],
}
} else { vec![] }
} else { vec![] }
}
_ => vec![],
}
}
_ => vec![],
};
// Filter by the user's partial input
let filtered: Vec<String> = values.into_iter()
.map(String::from)
.filter(|v| v.to_lowercase().contains(&request.argument.value.to_lowercase()))
.collect();
Ok(CompleteResult {
completion: CompletionInfo {
values: filtered,
total: None,
has_more: Some(false),
},
})
}
}
```
### Client-side
```rust
use rmcp::model::*;
let result = client.complete(CompleteRequestParams {
meta: None,
r#ref: Reference::Prompt(PromptReference {
name: "sql_query".into(),
}),
argument: ArgumentInfo {
name: "operation".into(),
value: "SEL".into(),
},
context: None,
}).await?;
// result.completion.values contains suggestions like ["SELECT"]
```
**Example:** [`examples/servers/src/completion_stdio.rs`](examples/servers/src/completion_stdio.rs)
---
## Notifications
Notifications are fire-and-forget messages -- no response is expected. They cover progress updates, cancellation, and lifecycle events. Both sides can send and receive them.
**MCP Spec:** [Notifications](https://modelcontextprotocol.io/specification/2025-11-25/basic/notifications)
### Progress notifications
Servers can report progress during long-running operations:
```rust
use rmcp::model::*;
// Inside a tool handler:
for i in 0..total_items {
process_item(i).await;
context.peer.notify_progress(ProgressNotificationParam {
progress_token: ProgressToken(NumberOrString::Number(i as i64)),
progress: i as f64,
total: Some(total_items as f64),
message: Some(format!("Processing item {}/{}", i + 1, total_items)),
}).await?;
}
```
### Cancellation
Either side can cancel an in-progress request:
```rust
// Send a cancellation
context.peer.notify_cancelled(CancelledNotificationParam {
request_id: the_request_id,
reason: Some("User requested cancellation".into()),
}).await?;
```
Handle cancellation in `ServerHandler` or `ClientHandler`:
```rust
impl ServerHandler for MyServer {
async fn on_cancelled(
&self,
params: CancelledNotificationParam,
_context: NotificationContext<RoleServer>,
) {
// Abort work for params.request_id
}
}
```
### Initialized notification
Clients send `initialized` after the handshake completes:
```rust
// Sent automatically by rmcp during the serve() handshake.
// Servers handle it via:
impl ServerHandler for MyServer {
async fn on_initialized(
&self,
_context: NotificationContext<RoleServer>,
) {
// Server is ready to receive requests
}
}
```
### List-changed notifications
When available tools, prompts, or resources change, tell the client:
```rust
context.peer.notify_tool_list_changed().await?;
context.peer.notify_prompt_list_changed().await?;
context.peer.notify_resource_list_changed().await?;
```
**Example:** [`examples/servers/src/common/progress_demo.rs`](examples/servers/src/common/progress_demo.rs)
---
## Subscriptions
Clients can subscribe to specific resources. When a subscribed resource changes, the server sends a notification and the client can re-read it.
**MCP Spec:** [Resources - Subscriptions](https://modelcontextprotocol.io/specification/2025-11-25/server/resources#subscriptions)
### Server-side
Enable subscriptions in the resources capability and implement the `subscribe()` / `unsubscribe()` handlers:
```rust
use rmcp::{ErrorData as McpError, ServerHandler, model::*, service::RequestContext, RoleServer};
use std::sync::Arc;
use tokio::sync::Mutex;
use std::collections::HashSet;
#[derive(Clone)]
struct MyServer {
subscriptions: Arc<Mutex<HashSet<String>>>,
}
impl ServerHandler for MyServer {
fn get_info(&self) -> ServerInfo {
ServerInfo {
capabilities: ServerCapabilities::builder()
.enable_resources()
.enable_resources_subscribe()
.build(),
..Default::default()
}
}
async fn subscribe(
&self,
request: SubscribeRequestParams,
_context: RequestContext<RoleServer>,
) -> Result<(), McpError> {
self.subscriptions.lock().await.insert(request.uri);
Ok(())
}
async fn unsubscribe(
&self,
request: UnsubscribeRequestParams,
_context: RequestContext<RoleServer>,
) -> Result<(), McpError> {
self.subscriptions.lock().await.remove(&request.uri);
Ok(())
}
}
```
When a subscribed resource changes, notify the client:
```rust
// Check if the resource has subscribers, then notify
context.peer.notify_resource_updated(ResourceUpdatedNotificationParam {
uri: "file:///config.json".into(),
}).await?;
```
### Client-side
```rust
use rmcp::model::*;
// Subscribe to updates for a resource
client.subscribe(SubscribeRequestParams {
meta: None,
uri: "file:///config.json".into(),
}).await?;
// Unsubscribe when no longer needed
client.unsubscribe(UnsubscribeRequestParams {
meta: None,
uri: "file:///config.json".into(),
}).await?;
```
Handle update notifications in `ClientHandler`:
```rust
impl ClientHandler for MyClient {
async fn on_resource_updated(
&self,
params: ResourceUpdatedNotificationParam,
_context: NotificationContext<RoleClient>,
) {
// Re-read the resource at params.uri
}
}
```
---
## Tasks (long-running tool invocations)
`rmcp` supports the [task-based tool invocation](https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/tasks)
flow defined in SEP-1319. Annotate a tool with `execution(task_support = "required" | "optional")`
and add `#[task_handler]` to your `ServerHandler` impl — `enqueue_task`, `tasks/list`, `tasks/get`,
`tasks/result`, and `tasks/cancel` are generated for you on top of an `OperationProcessor`.
```rust, ignore
#[tool(
description = "Sum two numbers after a 2-second delay",
execution(task_support = "required")
)]
async fn slow_sum(/* ... */) -> Result<CallToolResult, McpError> { /* ... */ }
#[tool_handler]
#[task_handler]
impl ServerHandler for TaskDemo {}
```
See [`servers_task_stdio`](examples/servers/src/task_stdio.rs) and the matching
[`clients_task_stdio`](examples/clients/src/task_stdio.rs) for a runnable end-to-end example.
## Examples
See [examples](examples/README.md).
## OAuth Support
See [Oauth_support](docs/OAUTH_SUPPORT.md) for details.
## Related Resources
- [MCP Specification](https://modelcontextprotocol.io/specification/2025-11-25)
- [Schema](https://github.com/modelcontextprotocol/specification/blob/main/schema/2025-11-25/schema.ts)
## Related Projects
### Extending `rmcp`
- [rmcp-actix-web](https://gitlab.com/lx-industries/rmcp-actix-web) - An `actix_web` backend for `rmcp`
- [rmcp-openapi](https://gitlab.com/lx-industries/rmcp-openapi) - Transform OpenAPI definition endpoints into MCP tools
### Built with `rmcp`
- [goose](https://github.com/block/goose) - An open-source, extensible AI agent that goes beyond code suggestions
- [apollo-mcp-server](https://github.com/apollographql/apollo-mcp-server) - MCP server that connects AI agents to GraphQL APIs via Apollo GraphOS
- [rustfs-mcp](https://github.com/rustfs/rustfs/tree/main/crates/mcp) - High-performance MCP server providing S3-compatible object storage operations for AI/LLM integration
- [containerd-mcp-server](https://github.com/jokemanfire/mcp-containerd) - A containerd-based MCP server implementation
- [rmcp-openapi-server](https://gitlab.com/lx-industries/rmcp-openapi/-/tree/main/crates/rmcp-openapi-server) - High-performance MCP server that exposes OpenAPI definition endpoints as MCP tools
- [nvim-mcp](https://github.com/linw1995/nvim-mcp) - A MCP server to interact with Neovim
- [terminator](https://github.com/mediar-ai/terminator) - AI-powered desktop automation MCP server with cross-platform support and >95% success rate
- [stakpak-agent](https://github.com/stakpak/agent) - Security-hardened terminal agent for DevOps with MCP over mTLS, streaming, secret tokenization, and async task management
- [video-transcriber-mcp-rs](https://github.com/nhatvu148/video-transcriber-mcp-rs) - High-performance MCP server for transcribing videos from 1000+ platforms using whisper.cpp
- [NexusCore MCP](https://github.com/sjkim1127/Nexuscore_MCP) - Advanced malware analysis & dynamic instrumentation MCP server with Frida integration and stealth unpacking capabilities
- [spreadsheet-mcp](https://github.com/PSU3D0/spreadsheet-mcp) - Token-efficient MCP server for spreadsheet analysis with automatic region detection, recalculation, screenshot, and editing support for LLM agents
- [hyper-mcp](https://github.com/hyper-mcp-rs/hyper-mcp) - A fast, secure MCP server that extends its capabilities through WebAssembly (WASM) plugins
- [rudof-mcp](https://github.com/rudof-project/rudof/tree/master/rudof_mcp) - RDF validation and data processing MCP server with ShEx/SHACL validation, SPARQL queries, and format conversion. Supports stdio and streamable HTTP transports with full MCP capabilities (tools, prompts, resources, logging, completions, tasks)
- [McpMux](https://github.com/mcpmux/mcp-mux) - Desktop app to configure MCP servers once at McpMux, connect every AI client (Cursor, Claude Desktop, VS Code, Windsurf) through a single encrypted local gateway with Spaces for project organization, FeatureSets to switch toolsets per client, and a built-in server registry
- [systemprompt-template](https://github.com/systempromptio/systemprompt-template) - Single-binary Rust runtime providing MCP governance — authentication, authorisation, rate-limiting, audit trails, and cost tracking for AI agents. Self-hosted, air-gap capable, 3,300+ req/s with sub-5ms governance overhead
## Development
### Tips for Contributors
See [docs/CONTRIBUTE.MD](docs/CONTRIBUTE.MD) to get some tips for contributing.
### Using Dev Container
If you want to use dev container, see [docs/DEVCONTAINER.md](docs/DEVCONTAINER.md) for instructions on using Dev Container for development.
