Mirror of https://github.com/modelcontextprotocol/rust-sdk — The official Rust SDK for the Model Context Protocol
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Andrei G 452fe2c50f
feat: implement context-aware completion (MCP 2025-06-18) (#396)
* feat: implement MCP completion specification 2025-06-18

Complete implementation of MCP completion specification with performance optimizations:

Core Features:
- Add CompletionContext for context-aware completion with previously resolved arguments
- Implement CompletionProvider trait with async support and dyn compatibility
- Create DefaultCompletionProvider with optimized fuzzy matching algorithm
- Add comprehensive validation and helper methods to CompletionInfo
- Update ServerHandler to handle completion/complete requests
- Add client convenience methods for prompt and resource completion

Performance Optimizations:
- Zero-allocation fuzzy matching using index-based scoring
- Top-k selection with select_nth_unstable instead of full sorting
- Pre-allocated vectors to avoid reallocations during matching
- Char-based case-insensitive matching to minimize string operations
- 5-8x performance improvement for large candidate sets

API Design:
- Context-aware completion supporting multi-argument scenarios
- Type-safe validation with MAX_VALUES limit (100 per MCP spec)
- Helper methods: with_all_values, with_pagination, validate
- Reference convenience methods: for_prompt, for_resource
- Client methods: complete_prompt_argument, complete_resource_argument

Testing:
- 17 comprehensive tests covering all functionality
- Schema compliance tests for MCP 2025-06-18 specification
- Performance tests with <100ms target for 1000 candidates
- Edge case and validation tests

Schema Updates:
- Add CompletionContext to JSON schema
- Update CompleteRequestParam with optional context field
- Maintain backward compatibility with existing API

* test: add comprehensive fuzzy matching tests for completion

Add three new test cases to enhance coverage of fuzzy matching algorithm:

- test_fuzzy_matching_with_typos_and_missing_chars: Tests subsequence matching
  with real-world scenarios including abbreviated patterns, case-insensitive
  matching, and complex file/package name completion

- test_fuzzy_matching_scoring_priority: Validates scoring system prioritizes
  exact matches > prefix matches > substring matches > subsequence matches

- test_fuzzy_matching_edge_cases: Covers boundary conditions including
  single character queries, oversized queries, and repeated characters

These tests ensure robust fuzzy search functionality for MCP completion
specification implementation with proper handling of user typos and
incomplete input patterns.

* feat: improve completion algorithms, add comprehensive tests and example

- Enhance fuzzy matching algorithm with acronym support for multi-word entries
- Add comprehensive scoring system for better relevance ranking
- Implement multi-level matching: exact, prefix, word prefix, acronym, substring
- Add context-aware completion scoring with proper priority ordering
- Optimize performance through efficient character-by-character matching
- Support case-insensitive acronym matching
- Improve code quality with clippy fixes and async fn syntax
- Add comprehensive test suite covering edge cases and acronym matching
- Create completion example server demonstrating weather-related prompts

* fix(test): typos

* refactor: improve completion API and replace example with SQL query builder

- Remove DefaultCompletionProvider from library core
- Move completion logic to examples following review feedback
- Update CompletionContext.argument_names() to return Iterator for better performance
- Replace tech search example with SQL query builder demonstrating progressive completion
- Add context-aware completion that adapts based on filled arguments
- Use proper Option types for optional SQL fields (columns, where_clause, values)
- Demonstrate real-world value of argument_names() method for dynamic completion flow

The SQL query builder showcases:
• Progressive field availability based on operation type
• Context validation using argument_names()
• Proper Optional field handling
• Smart completion that guides user through multi-step form

* fix: fmt
2025-09-08 14:44:49 +08:00
.devcontainer Adopt Devcontainer for Development Environment (#81) 2025-04-02 12:16:49 +08:00
.github chore(deps): bump actions/labeler from 5 to 6 (#419) 2025-09-05 09:05:11 +08:00
crates feat: implement context-aware completion (MCP 2025-06-18) (#396) 2025-09-08 14:44:49 +08:00
docs docs(README): update zh_cn README (#336) 2025-07-29 02:41:38 +08:00
examples feat: implement context-aware completion (MCP 2025-06-18) (#396) 2025-09-08 14:44:49 +08:00
.gitignore feat: Add prompt support (#351) 2025-08-21 11:22:19 +08:00
Cargo.toml chore: release v0.6.3 (#420) 2025-09-04 17:23:18 -04:00
clippy.toml feat: add clippy config (#162) 2025-05-08 10:15:17 +08:00
justfile chore: cov settings, and fix serveral building warnings (#281) 2025-06-25 14:30:45 +08:00
LICENSE Initial commit 2025-02-18 10:55:26 +00:00
README.md docs: add nvim-mcp project built by rmcp (#422) 2025-09-08 09:16:49 +08:00
rust-toolchain.toml Move whole rmcp crate to offcial rust sdk (#44) 2025-03-27 17:33:41 -04:00
rustfmt.toml style: fmt the project (#54) 2025-03-28 23:50:46 +08:00

RMCP

Crates.io Version

Coverage

An official Rust Model Context Protocol SDK implementation with tokio async runtime.

This repository contains the following crates:

  • rmcp: The core crate providing the RMCP protocol implementation (If you want to get more information, please visit rmcp)
  • rmcp-macros: A procedural macro crate for generating RMCP tool implementations (If you want to get more information, please visit rmcp-macros)

Usage

Import the crate

rmcp = { version = "0.2.0", features = ["server"] }
## or dev channel
rmcp = { git = "https://github.com/modelcontextprotocol/rust-sdk", branch = "main" }

Third Dependencies

Basic dependencies:

Build a Client

Start a client
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(())
}

Build a Server

Build a transport
use tokio::io::{stdin, stdout};
let transport = (stdin(), stdout());
Build a service

You can easily build a service by using ServerHandler or ClientHandler.

let service = common::counter::Counter::new();
Start the server
// this call will finish the initialization process
let server = service.serve(transport).await?;
Interact with the server

Once the server is initialized, you can send requests or notifications:

// request
let roots = server.list_roots().await?;

// or send notification
server.notify_cancelled(...).await?;
Waiting for service shutdown
let quit_reason = server.waiting().await?;
// or cancel it
let quit_reason = server.cancel().await?;

Examples

See examples

OAuth Support

See oauth_support for details.

Extending rmcp

Built with rmcp

  • rustfs-mcp - High-performance MCP server providing S3-compatible object storage operations for AI/LLM integration
  • containerd-mcp-server - A containerd-based MCP server implementation
  • rmcp-openapi-server - High-performance MCP server that exposes OpenAPI definition endpoints as MCP tools
  • nvim-mcp - A MCP server to interact with Neovim

Development

Tips for Contributors

See docs/CONTRIBUTE.MD to get some tips for contributing.

Using Dev Container

If you want to use dev container, see docs/DEVCONTAINER.md for instructions on using Dev Container for development.