AI Agent SDK Comparison — Claude Agent SDK vs OpenAI Responses API vs LangChain (2026)
July 2026 update — This comparison was written as of May 2026. Two big changes have happened since. Anthropic released the new Claude 5 family (Fable 5), and Claude Code’s default model changed to Sonnet 5 (native 1M-token context). The criteria for choosing a framework themselves (comparing the agent loop, tool calls, and how it’s … Read more