In a 2026 comparison of AI agent frameworks, LangGraph, CrewAI, and the Claude Agent SDK differ fundamentally on control flow. LangGraph lets developers author a graph where nodes are functions and edges are routing logic, making structure code the developer wrote. CrewAI has the framework resolve ordering and hand-offs after developers declare agents with roles, goals, and backstories. The Claude Agent SDK lets the model pick the next action inside a loop, with no graph. Crash recovery granularity splits them: LangGraph resumes at the last completed node, CrewAI at the last Flow step, and the Claude Agent SDK at the session. Only LangGraph can replay a past run from a stored checkpoint; CrewAI’s replay is limited, and the Claude Agent SDK provides transcripts. LangGraph and CrewAI work with any model provider, while the Claude Agent SDK runs on Anthropic models only. CrewAI reaches a working multi-agent draft fastest, LangGraph costs the most to write and least to maintain, and the Claude Agent SDK needs the least scaffolding for open-ended tool work. Determinism is high in LangGraph, medium inside CrewAI Flows but low inside Crews, and absent by design in the Claude Agent SDK. Gartner expects 40% of enterprise applications to ship with task-specific agents by the end of 2026, up from under 5% in 2025.