Framework comparisons argue about graphs versus crews versus handoffs, but the metaphor stops mattering by week three. What you cannot re-pick eighteen months in is where a run lives, what resume means after a crash, and whether a human can pause a half-finished task — so choose on the state model and the rest of the comparison resolves itself.
A 128K-token context window degrades past the first thousand tokens and vanishes the moment the session ends. The agent-memory infrastructure market crossed $6 billion in 2026 because "throw it all in the context" stopped being a strategy — and four frameworks now bet differently on what memory should rank, store, and forget.
Four orchestration frameworks let you wire up the same workflow — and the feature lists nearly match. The thing that decides which one survives production is invisible there: where your agent's state actually lives.
Three of 2026’s fastest-growing open-source agents look almost identical on a feature list — and behave like completely different species the moment you run them. A diagram-by-diagram tour of where the architectures diverge.