Add ell - lightweight functional prompt engineering framework

- 5,872+ stars, MIT licensed
- Built by ex-OpenAI researcher (MadcowD)
- Automatic prompt versioning and Ell Studio for optimization
- Active development (last commit June 2025)

Author: alvinreal

README.md

@@ -385,6 +385,7 @@
 - **[Griptape](https://github.com/griptape-ai/griptape)** ![GitHub stars](https://img.shields.io/github/stars/griptape-ai/griptape?style=social) - Modular Python framework for AI agents and workflows with chain-of-thought reasoning, tools, and memory. Enforces structures like sequential pipelines and DAG-based workflows for predictable AI systems. Apache 2.0 licensed.
 - **[Langroid](https://github.com/langroid/langroid)** ![GitHub stars](https://img.shields.io/github/stars/langroid/langroid?style=social) - Harness LLMs with multi-agent programming. Mature tool calling system based on Pydantic, supports hundreds of LLM providers including OpenAI and local servers. Built for robust agent behavior in real-world use cases. MIT licensed.
 - **[Marvin](https://github.com/PrefectHQ/marvin)** ![GitHub stars](https://img.shields.io/github/stars/PrefectHQ/marvin?style=social) - Python framework for structured outputs and agentic AI workflows. Simplifies LLM interactions with type-safe interfaces, automatic schema generation, and built-in observability. From the creators of Prefect. Apache 2.0 licensed.
+- **[ell](https://github.com/MadcowD/ell)** ![GitHub stars](https://img.shields.io/github/stars/MadcowD/ell?style=social) - Lightweight, functional prompt engineering framework. Treats prompts as programs (LMPs) with automatic versioning, serialization, and Ell Studio for prompt optimization. Built by ex-OpenAI researcher. MIT licensed.
 
 - **[Burr](https://github.com/apache/burr)** ![GitHub stars](https://img.shields.io/github/stars/apache/burr?style=social) - Apache incubating framework for building stateful AI applications (chatbots, agents, simulations). Monitor, trace, persist, and execute on your own infrastructure with built-in UI and pluggable memory. Apache 2.0 licensed.
 - **[KaibanJS](https://github.com/kaiban-ai/KaibanJS)** ![GitHub stars](https://img.shields.io/github/stars/kaiban-ai/KaibanJS?style=social) - JavaScript-native framework for building and managing multi-agent systems with a Kanban-inspired approach. Visual task board for AI agents with real-time collaboration features. MIT licensed.