google/adk-go

Dify is an open-source LLM app platform that packages a visual workflow/agent builder, RAG pipeline, model provider management, and app-level APIs into one self-hostable (or cloud) stack, aimed at teams who want to skip stitching those pieces together themselves.

LangChain is a Python framework (MIT-licensed) for assembling LLM-powered apps and agents from standard components: model wrappers, prompts, retrieval, tools, and chain/graph orchestration handed off to LangGraph. It's for developers gluing together model providers and data sources, not for a single prompt-response call.

AutoGPT is an open-source platform for building, deploying, and running AI agents that automate complete workflows. Users can define tasks in plain English using AutoPilot or visually construct steps with the Build interface. The project offers both a managed, hosted platform that handles infrastructure and model access, and a self-hosting option where users provide their own infrastructure and API keys. AutoGPT agents are designed to automate tasks across various domains, including executive operations, sales, and engineering, and integrate with over 45 platforms like Gmail and GitHub. While its `autogpt_platform/` component is licensed under Polyform Shield, the original `classic/` agent and other parts of the project use the MIT License.

prompts.chat is the largest open-source prompt library for AI, formerly called Awesome ChatGPT Prompts. It hosts curated prompts in CSV and Markdown, available as a public website, Hugging Face dataset, or self-hosted instance. The project supports multiple LLM providers including ChatGPT, Claude, Gemini, Llama, and Mistral. Self-hosting uses a Next.js setup wizard that configures authentication via GitHub, Google, or Azure AD, with PostgreSQL as the recommended database. CLI access, an MCP server, and a Claude Code plugin extend its reach into developer workflows. The codebase is MIT-licensed while prompt data falls under CC0. Its 166k GitHub stars make it an AI resource on the platform with 166k GitHub stars, and it has been cited by Harvard, Columbia, and Forbes.