175 listed
Harnesses & SDKs
Frameworks and SDKs for building agents: the Claude Agent SDK, OpenAI Agents SDK, LangGraph, CrewAI and many more. Each page lists languages, packages, MCP and A2A support and how it orchestrates agents, with a link to the page every fact came from.
Showing 1–17 of 17
| Name | Language | Stars | Downloads / month (approx.) | MCP | A2A | Multi-agent |
|---|---|---|---|---|---|---|
| GitHub Copilot SDK Multi-language SDKs for embedding the GitHub Copilot agent runtime, with planning, tool calls and file edits, in your apps. | Python, TypeScript, Go, C#, Java, Rust | 10.6K | ~5M | Not stated | Not stated | — |
| AgentScope Java Java framework for distributed, long-running agents with typed event streams, permission gating, middleware and subagents. | Java | 6.1K | — | Not stated | Built in | Yes |
| Ax DSPy-style toolkit for typed LLM signatures, agents and flows, TypeScript-first with Python, Java, C++, Go and Rust libraries. | TypeScript, Python, Java, c++, Go, Rust | 3K | ~116.4K | Not stated | Not stated | Yes |
| atmosphere Java runtime for AI agents that streams tokens and tool events over WebSocket, SSE or gRPC, with human approvals. | Java | 3.8K | — | Built in | Built in | Yes |
| Google Agent Development Kit (ADK) Open-source toolkit for building, evaluating and deploying agents in Python, TypeScript, Go, Java and Kotlin, tuned for Gemini but model-agnostic. | Python, TypeScript, Go, Java, Kotlin | 22K | ~10.1M | Built in | Not stated | Yes |
| LangChain4j Java library with one API over LLM providers and vector stores, plus tools, RAG and integrations for Quarkus and Spring Boot. | Java | 13.3K | — | Not stated | Not stated | — |
| Spring AI Alibaba Java framework for agentic, workflow and multi-agent AI apps, with graph workflows, MCP and A2A support. | Java | 11.1K | — | Built in | Built in | Yes |
| Spring AI Java application framework from the Spring project with portable chat and embedding APIs, tool calling and vector stores. | Java | 9.6K | — | Not stated | Not stated | — |
| Koog Kotlin and Java framework for AI agents with tools, graph workflows, MCP, streaming and multiplatform targets. | Kotlin, Java | 4.6K | — | Built in | Not stated | — |
| Embabel JVM framework for agentic flows that plan toward goals, mixing LLM calls with code and domain models, usable from Kotlin or Java. | Kotlin, Java | 4.5K | — | Not stated | Not stated | — |
| attestix Python toolkit for signed identities, verifiable credentials and delegated authority for AI agents, with MCP and REST interfaces. | Python, JavaScript, Go, Java | 839 | ~690 | Built in | Not stated | — |
| Quarkus LangChain4j Quarkus extensions that connect LangChain4j to Quarkus apps, with declarative AI services and LLM, tool and embedding support. | Java | 326 | — | Not stated | Not stated | — |
| LangGraph4j Java library for stateful, multi-agent LLM applications built as cyclical graphs, designed to work with langchain4j and Spring AI. | Java | 2.1K | — | Not stated | Not stated | Yes |
| Semantic Kernel Model-agnostic SDK for building agents and multi-agent systems in Python, .NET and Java; Microsoft names Agent Framework as its successor. | Python, C#, Java | 28.7K | ~332.1K | Built in | Not stated | Yes |
| ADK for Java Code-first Java toolkit for building and testing AI agents, with multi-agent hierarchies, a dev UI and Maven packages. | Java | 1.8K | — | Built in | Built in | Yes |
| Akka SDK SDK for building durable, responsive services, including agentic AI services, that cluster automatically and deploy to any infrastructure. | Java | 30 | — | Not stated | Not stated | Yes |
| Semantic Kernel for Java Java SDK for calling LLMs such as OpenAI, Azure OpenAI and Hugging Face, with plugins that chain functions and planners. | Java | 276 | — | Not stated | Not stated | — |