Updated April 29, 2026
Agno (formerly Phidata) is an open-source Python framework for building production-grade AI agents and multi-agent systems. 39K+ GitHub stars, 23+ LLM providers supported, 100+ pre-built tool integrations, MCP-compatible. Includes AgentOS — a stateless FastAPI runtime — and a control plane UI for monitoring.
Atomic Agents is an open-source agent framework built on top of Instructor, designed for building AI agents with a focus on structured outputs and composability. It extends Instructor's structured output capabilities into a full agentic framework with tool use, multi-step planning, and agent orchestration, emphasizing type-safe, schema-driven agent development.
Core capabilities each platform advertises.
What each tool does well, and the limitations to keep in mind.
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Agno has emerged as one of the fastest-growing AI agent frameworks in 2026 — 39,100+ stars and a 424-contributor community.
Read full reviewChoose Agno if you wantChoose if you want
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Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 500+ models through one gateway.