Alternatives to Koog

OpenManus is an open-source framework for building general-purpose AI agents, developed by core contributors from the MetaGPT community. It provides a modular architecture with planning agents, reactive agents, and tool-calling agents that can execute code, browse the web, search for information, and handle files. Built as the open alternative to Manus AI, it gained over 55,000 GitHub stars and supports multi-agent collaboration with real-time execution feedback.

Agent Zero is an open-source general-purpose AI agent framework with 16,700+ GitHub stars that uses the computer itself as a tool. Unlike structured orchestration frameworks, it provides full transparency where every thought, action, and tool call is visible and editable in real time, supporting 100+ extensible skills.

Parlant is an open-source framework that adds behavioral governance to conversational AI agents. Instead of relying on prompt engineering alone, it lets teams define explicit policies, conversation guidelines, and behavioral rules that agents follow predictably across multi-turn interactions. Parlant sits between the LLM and the user-facing interface, enforcing consistent agent behavior for customer support, sales, and service automation use cases.