How does Claude Agent SDK compare with the alternatives?
The OpenAI Agents SDK is a lightweight loop with handoffs, guardrails, sessions, and tracing built in, aimed at OpenAI models with adapters for others. The Claude Agent SDK ships Claude Code's file and shell tools, subagents, and permission rules, and starts a CLI process per session. Decide on the model you are committed to, and on whether the agent needs a shell.
LangGraph has your code define every step and checkpoints state between them, across model providers. The Claude Agent SDK lets Claude plan the steps with Claude Code's tools and subagents. Pick LangGraph when the path must be explicit and durable, and the SDK when Claude should drive the work.
Vercel's AI SDK is a TypeScript toolkit for model calls, tool loops, and streaming UI across providers, running inside your web stack. The Claude Agent SDK brings a full Claude Code harness with file and shell tools in a separate process. Chat inside a web app starts with the AI SDK, and agents that work on files start with the Claude Agent SDK.
On the Claude API, the Messages endpoint and its tool runner leave the loop, tools, and state to your code, with no subprocess. The Agent SDK supplies Claude Code's loop, tools, and context compaction at the cost of a CLI process per session. Multi-tenant web backends usually fit the API, and file-heavy agents fit the SDK.
