Agent frameworks and SDKs for building MCP servers

Pi

NewcodingOpen source

Minimal, extensible open-source terminal coding agent and agent toolkit from Earendil, with a multi-provider LLM API, TypeScript SDK, RPC mode and installable extensions, skills and themes.

Added Oct 18, 2026

LiteLLM

Newagent infraOpen source + cloud

Open-source AI gateway and Python SDK that calls 100+ LLM providers in the OpenAI format, with cost tracking, guardrails, load balancing and logging.

Added Oct 18, 2026

OpenAI Agents SDK (Python)

frameworksOpen source

OpenAI's Python SDK for building multi-agent workflows; v0.23.0/0.23.1 released Oct 1-2.

Added Oct 14, 2026

FastMCP

MCP serversOpen source

Pythonic framework for building MCP servers and clients quickly.

Added Oct 16, 2026

MCP Python SDK

MCP serversOpen source

Official Python SDK for building Model Context Protocol servers and clients.

Added Oct 16, 2026

MCP TypeScript SDK

MCP serversOpen source

Official TypeScript SDK for building MCP servers and clients.

Added Oct 16, 2026

mcp-use

MCP serversOpen source

Full-stack MCP framework for building MCP servers, MCP apps and agents that connect to them.

Added Oct 16, 2026

Claude Agent SDK (Python)

NewframeworksOpen source

Anthropic's Python SDK for building agents on Claude Code's agent loop, with the CLI bundled, custom tools and hooks.

Added Oct 18, 2026

Sphere SDK

NewcryptoOpen source

TypeScript SDK that gives autonomous agents an identity and wallet on the Unicity network to find, negotiate and settle payments with other agents.

Added Oct 18, 2026

MCP Go SDK

NewMCP serversOpen source

Official Go SDK for building Model Context Protocol servers and clients, maintained with Google.

Added Oct 18, 2026

MCP C# SDK

MCP serversOpen source

Official C# SDK for building MCP servers and clients, maintained with Microsoft.

Added Oct 16, 2026

MCP Rust SDK

MCP serversOpen source

Official Rust SDK for the Model Context Protocol.

Added Oct 16, 2026

Antigravity SDK

NewframeworksOpen source

Google's Python SDK for building stateful AI agents powered by Antigravity and Gemini, abstracting the agent loop and runtime.

Added Oct 18, 2026

MCP Java SDK

MCP serversOpen source

Official Java SDK for MCP servers and clients.

Added Oct 16, 2026

TanStack AI

frameworksOpen source

Type-safe, provider-agnostic TypeScript SDK for chat, tool calling and agents.

Added Oct 16, 2026

NitroStack

NewMCP serversOpen source + cloud

TypeScript framework with decorators and dependency injection for building, testing and deploying MCP servers and MCP apps, with a companion desktop studio.

Added Oct 17, 2026

Workflow SDK

NewframeworksOpen source

Vercel's TypeScript SDK for building durable, reliable and observable apps and AI agents.

Added Oct 18, 2026

Skybridge

NewMCP serversOpen source

Full-stack TypeScript and React framework for building MCP Apps and ChatGPT Apps.

Added Oct 18, 2026

MCP PHP SDK

NewMCP serversOpen source

Official PHP SDK for building MCP servers and clients, maintained with the PHP Foundation and Symfony.

Added Oct 18, 2026

MCP Kotlin SDK

NewMCP serversOpen source

Official Kotlin Multiplatform SDK for building MCP servers and clients on JVM, Native, JS and Wasm, maintained with JetBrains.

Added Oct 19, 2026

Arcade

Newagent infraOpen source + cloud

Actions runtime for enterprise agents with thousands of prebuilt authenticated tools, plus an open-source framework for building your own MCP servers.

Added Oct 18, 2026

AgentEnv Framework

Newevals & observabilityOpen source

AgentEnv Framework is Scale AI's open-source Python SDK and CLI for building RL environments for agents: containerized worlds with realistic apps and data behind an MCP gateway, plus tasks (as DAGs) that grade any agent in any sandbox.

Added Oct 20, 2026