Rust Mcp Sdk

PMCP - Pragmatic Model Context Protocol

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> Production-grade Rust implementation of the Model Context Protocol (MCP) - 16x faster than TypeScript, built with Toyota Way quality principles

Overview

PMCP is a complete MCP ecosystem for Rust, providing everything you need to build, test, and deploy production-grade MCP servers — in Rust, or from configuration alone:

• 🧩 Config-Driven Servers - Build SQL & OpenAPI/HTTP MCP servers from a config.toml, or serve a governed Excel workbook from a compiled bundle — all no Rust required (pmcp-server-toolkit, pmcp-sql-server, pmcp-openapi-server, pmcp-workbook-server)
• 🦀 pmcp SDK - High-performance Rust crate with full MCP protocol support
• ⚡ cargo-pmcp - CLI toolkit for scaffolding, testing, and development
• 📚 pmcp-book - Comprehensive reference guide with 27 chapters
• 🎓 pmcp-course - Hands-on course with quizzes and exercises
• 🤖 AI Agents - Kiro and Claude Code configurations for AI-assisted development

Why PMCP?

• Performance: 16x faster than TypeScript SDK, 50x lower memory
• Safety: Rust's type system + zero unwrap() in production code
• Quality: Toyota Way principles - zero technical debt tolerance
• Complete: SDK, tooling, documentation, and AI assistance in one ecosystem

Quick Start

Choose your path based on experience and preference:

🧩 Path 1: Config-Only Servers — No Rust Required (SQL & OpenAPI)

New in v2.9 — this removes the biggest blocker to putting organizational data behind MCP: you no longer need a Rust programmer. Describe a production MCP server over a SQL database or any OpenAPI / HTTP backend in a config.toml — declare the backend, a handful of curated tools, and a Code Mode policy — and a prebuilt binary serves it. No Rust, no recompiling. Curated tools cover the common ~20%; Code Mode handles the long-tail ~80% by generating queries against your schema/spec under a static, default-deny policy. A business analyst curates the API slice in config; the toolkit does the rest.

SQL — SQLite / Postgres / MySQL / Athena (runnable from a checkout of this repo):

cargo install pmcp-sql-server

# Seed a tiny demo DB, then serve it from config alone — two curated tools
# (list_books, books_by_author) + Code Mode for the long tail.
sqlite3 /tmp/pmcp-sqlite-explorer.db  --template `):
- `minimal` - Empty structure for custom servers
- `calculator` - Arithmetic operations (learning)
- `complete_calculator` - Full-featured reference implementation
- `sqlite_explorer` - Hand-coded Rust database browser (escape hatch)

**Config-driven kinds** (`cargo pmcp new  --kind ` — TOML-driven, no per-tool Rust):
- `sql-server` - SQL MCP server over SQLite / Postgres / MySQL / Athena from `config.toml`
- `openapi-server` - MCP server over any OpenAPI / HTTP backend from `config.toml`
- `workbook-server` - MCP server over a governed Excel workbook, served from a compiled `bundle@version` directory

**Learn more**: [cargo-pmcp Guide](cargo-pmcp/README.md)

---

### 🦀 Path 4: pmcp SDK Directly (For Fine-Grained Control)

Use the pmcp crate directly for maximum control:

**Installation:**
```toml
[dependencies]
pmcp = "2.0"
tokio = { version = "1", features = ["full"] }
serde = { version = "1", features = ["derive"] }
schemars = "0.8"  # For type-safe tools

Type-safe server example:

use pmcp::{ServerBuilder, TypedTool, RequestHandlerExtra, Error};
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};

#[derive(Debug, Deserialize, Serialize, JsonSchema)]
#[schemars(deny_unknown_fields)]
struct WeatherArgs {
    #[schemars(description = "City name")]
    city: String,

    #[schemars(description = "Number of days (1-5)")]
    days: Option,
}

#[derive(Debug, Serialize, JsonSchema)]
struct WeatherOutput {
    temperature: f64,
    conditions: String,
}

async fn get_weather(args: WeatherArgs, _extra: RequestHandlerExtra) -> pmcp::Result {
    // Validate
    if args.city.is_empty() {
        return Err(Error::validation("City cannot be empty"));
    }

    let days = args.days.unwrap_or(1);
    if !(1..=5).contains(&days) {
        return Err(Error::validation("Days must be 1-5"));
    }

    // Call weather API...
    Ok(WeatherOutput {
        temperature: 72.0,
        conditions: "Sunny".to_string(),
    })
}

#[tokio::main]
async fn main() -> pmcp::Result {
    let server = ServerBuilder::new()
        .name("weather-server")
        .version("1.0.0")
        .tool("get-weather", TypedTool::new("get-weather", |args, extra| {
            Box::pin(get_weather(args, extra))
        }).with_description("Get weather forecast for a city"))
        .build()?;

    server.run_stdio().await?;
    Ok(())
}

Learn more: pmcp-book | pmcp-course | API Documentation

---

PMCP Ecosystem Components

🦀 pmcp SDK (The Crate)

High-performance Rust implementation of the MCP protocol.

Key Features:

• Type-Safe Tools: Automatic JSON schema generation from Rust types
• Multiple Transports: stdio, HTTP/SSE, WebSocket, WASM
• OAuth Support: Full auth context pass-through
• Workflows: Multi-step orchestration with array indexing support
• MCP Apps: Rich HTML UI widgets with live preview and browser DevTools
• MCP Tasks: Shared client/server state with task lifecycle management
• Agent Skills (SEP-2640): Register an Agent Skill in ~5 lines and serve it on BOTH a SEP-2640 skill surface AND a parallel MCP prompt fallback — byte-equal by construction (skills feature, opt-in)
• Tower Middleware: DNS rebinding protection, CORS, security headers
• Typed Client Helpers: call_tool_typed, get_prompt_typed, and auto-paginating list_all_* with bounded safety cap
• Performance: 16x faster than TypeScript, SIMD-accelerated parsing
• Quality: Zero unwrap(), comprehensive error handling

Latest Version: pmcp = "2.9"

Documentation:

• API Reference
• pmcp-book
• [Examples](examples/)

---

⚡ cargo-pmcp (CLI Toolkit)

Full-lifecycle development toolkit — from scaffolding to production deployment.

cargo install cargo-pmcp

cargo pmcp new my-workspace             # Scaffold a new workspace
cargo pmcp add server my-server         # Add a server with best-practice template
cargo pmcp dev --server my-server       # Dev server with hot-reload
cargo pmcp test --server my-server      # Auto-generated scenario tests
cargo pmcp loadtest run                 # Load test with latency percentiles
cargo pmcp pentest run                  # Security audit (32 checks, SARIF output)
cargo pmcp preview --open               # Browser-based widget preview
cargo pmcp workbook explain wb.xlsx     # Preview an Excel workbook's MCP tool surface
cargo pmcp deploy --target aws-lambda   # Deploy to AWS Lambda, GCR, or Cloudflare
cargo pmcp deploy logs --tail           # Stream production logs

Covers the full development lifecycle: scaffolding, dev mode, testing, load testing, security pentesting, MCP Apps preview, schema management, multi-target deployment, secrets, and OAuth setup.

Full command reference: [cargo-pmcp Guide](cargo-pmcp/README.md)

---

🧩 Config-Driven Servers (No Rust)

Build production MCP servers over SQL and HTTP backends from a config.toml alone — the toolkit synthesizes curated tools + a Code Mode long tail, so exposing organizational data over MCP no longer needs a Rust programmer.

| Crate | What it is | | ----- | ---------- | | [pmcp-server-toolkit](crates/pmcp-server-toolkit) | The backend-agnostic library: config types, the [[tools]] synthesizer, Code Mode wiring, and the connector/auth seams that the binaries below build on. | | [pmcp-sql-server](crates/pmcp-sql-server) | Shape-A binary serving a SQL database (SQLite / Postgres / MySQL / Athena) from config.toml + a schema file. Ships a runnable [sqlite-explorer](crates/pmcp-sql-server/examples/sqlite-explorer.toml) example. | | [pmcp-openapi-server](crates/pmcp-openapi-server) | Shape-A binary serving any OpenAPI / HTTP backend, with six outgoing-auth models (incl. OAuth passthrough). Ships [london-tube](crates/pmcp-openapi-server/examples/london-tube.toml) (apikey) and [contoso-m365](crates/pmcp-openapi-server/examples/contoso-m365.toml) (oauthpassthrough, Microsoft Graph + Excel) examples. | | [pmcp-workbook-server](crates/pmcp-workbook-server) | Shape-A binary serving a governed Excel workbook as one named MCP tool per output table (e.g. calculate_tax, estimate_refund) plus infrastructure tools (explain / get_manifest / diff_version / render_workbook) from a compiled bundle@version directory alone — no config.toml, no schema. The Excel reader and JS code-mode are compile-time only and absent from the served binary (purity gate). | | [pmcp-toolkit-postgres](crates/pmcp-toolkit-postgres) / [-mysql](crates/pmcp-toolkit-mysql) / [-athena](crates/pmcp-toolkit-athena) | Per-backend SQL connectors for the toolkit. |

These binaries have cargo pmcp new --kind {sql-server,openapi-server,workbook-server} scaffold siblings that generate the same config-driven server as a small, deployable crate. See Path 1 above and the Config-Driven SQL Servers / OpenAPI / Config-Driven Workbook Servers chapters in the pmcp-book.

---

📚 pmcp-book (Reference Guide)

27-chapter comprehensive reference guide to building MCP servers with pmcp.

📖 Read Online

Coverage:

• Getting Started: Installation, first server, quick start tutorial
• Core Concepts: Tools, resources, prompts, error handling
• Advanced Features: Auth, transports, middleware, progress tracking
• Real-World: Production servers, testing, deployment, performance
• Examples & Patterns: Complete examples and design patterns
• TypeScript Migration: Complete compatibility guide
• Advanced Topics: Custom transports, AI-assisted development

Local development:

make book-serve    # Serve at http://localhost:3000
make book-open     # Build and open in browser

---

🎓 pmcp-course (Hands-On Learning)

Interactive course with quizzes, exercises, and real-world projects for mastering MCP development.

🎓 Start the Course

Course Structure:

• Part I: Foundations - MCP concepts, first server, typed tools
• Part II: Core Concepts - Tools, resources, prompts, validation
• Part III: Deployment - AWS Lambda, Cloudflare Workers, Google Cloud Run
• Part IV: Testing - Local testing, CI/CD, regression testing
• Part V: Security - OAuth 2.0, identity providers, multi-tenant
• Part VI: AI-Assisted Dev - Claude Code, feedback loops, collaboration
• Part VII: Observability - Middleware, logging, metrics
• Part VIII: Advanced - Server composition, MCP Apps (experimental)

Features:

• Interactive quizzes after each chapter
• Hands-on exercises with solutions
• Real-world project examples
• Best practices from production servers

Local development:

cd pmcp-course && mdbook serve    # Serve at http://localhost:3000

---

🤖 ai-agents (AI-Assisted Development)

AI agent configurations that teach Kiro and Claude Code how to build MCP servers.

Supported AI Assistants:

Kiro (Steering Files) - 10,876 lines of persistent MCP expertise

• Always-active knowledge in every conversation
• Comprehensive testing and observability guidance
• [Installation Guide](ai-agents/kiro/mcp-developer-power/)

Claude Code (Subagent) - ~750 lines of focused MCP knowledge

• On-demand invocation for MCP tasks
• Quick scaffolding and implementation
• [Installation Guide](ai-agents/claude-code/)

What AI agents know:

• MCP protocol concepts and patterns
• cargo-pmcp workflow (never creates files manually)
• Type-safe tool implementation
• Testing strategies (unit, integration, property, fuzz)
• Production observability (logging, metrics)
• Toyota Way quality standards

Community implementations welcome:

• GitHub Copilot, Cursor, Cline, and others
• [Contribution Guide](ai-agents/README.md)

Learn more: AI-Assisted Development Course | [ai-agents/](ai-agents/)

---

🎨 MCP Apps (Rich UI Widgets)

Build rich HTML UI widgets served from MCP servers — works with ChatGPT, Claude, and other MCP clients.

What it does:

• Preview: Live widget preview with dual proxy/WASM bridge modes
• Author: File-based widgets in widgets/ directory with hot-reload
• Scaffold: cargo pmcp app new generates a complete MCP Apps project
• Publish: ChatGPT-compatible manifest and standalone demo landing pages
• Test: 20 E2E browser tests via chromiumoxide CDP

Quick start:

# Scaffold a new MCP Apps project
cargo pmcp app new my-widget-app
cd my-widget-app

# Run the server
cargo run

# Preview in browser (separate terminal)
cargo pmcp preview --url http://localhost:3000 --open

# Generate deployment artifacts
cargo pmcp app build --url https://my-server.example.com

Examples:

• [Chess App](examples/mcp-apps-chess/) — Interactive chess board with move validation
• [Map App](examples/mcp-apps-map/) — Leaflet.js geospatial city explorer
• [Data Viz App](examples/mcp-apps-dataviz/) — Chart.js dashboard with SQL queries

Learn more: [Widget Runtime](packages/widget-runtime/) | [Preview Server](crates/mcp-preview/) | [E2E Tests](crates/mcp-e2e-tests/)

---

Latest Release: v2.0.0

PMCP v2.0 — aligned with the MCP TypeScript SDK v2.0 release (2026-03-22):

• Protocol v2025-11-25: Full alignment with the latest MCP specification, backward compatible with 2024-11-05
• MCP Apps: Rich interactive HTML UI widgets served from MCP servers — works with ChatGPT, Claude Desktop, and other MCP clients. Live preview with browser-style DevTools (resizable panel, network/events/protocol/bridge tabs)
• MCP Tasks: Experimental shared client/server state with DynamoDB-backed task lifecycle management and task variables
• Conformance Test Suite: 19-scenario conformance engine across 5 domains with cargo pmcp test conformance and mcp-tester conformance CLI integration
• Tower Middleware: DNS rebinding protection, CORS with origin-locked headers, configurable security headers — production-ready HTTP stack
• PMCP Server: MCP server exposing SDK developer tools (test, scaffold, schema export) via Streamable HTTP, deployed on AWS Lambda
• Uniform Constructor DX: Default impls, builders, and constructors for all protocol types — dramatically improved ergonomics
• 60+ Examples: Comprehensive coverage of all SDK features

Full changelog: [CHANGELOG.md](CHANGELOG.md)

---

Core Features

🚀 Transport Layer

• stdio: Standard input/output for CLI integration
• HTTP/SSE: Streamable HTTP with Server-Sent Events
• WebSocket: Full-duplex with auto-reconnection
• WASM: Browser and Cloudflare Workers support

🛠️ **Type-S

…

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: paiml
• Source: paiml/rust-mcp-sdk
• License: MIT
• Homepage: https://paiml.github.io/rust-mcp-sdk/

Install and usage instructions live in the source repository linked above.