LangGraph Checkpointer: Persist and Resume Agent State (2026)
Make a LangGraph agent durable with a checkpointer: attach SqliteSaver in one line, crash the graph on purpose, and resume from disk without re-running the Claude call.
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11 posts in this category.
Make a LangGraph agent durable with a checkpointer: attach SqliteSaver in one line, crash the graph on purpose, and resume from disk without re-running the Claude call.
A runnable 2026 tutorial for turning a local MCP server into a remote one over Streamable HTTP. Serve tools with FastMCP, test the endpoint with curl and MCP Inspector, validate the Origin header, add a bearer token, then connect Claude. Covers the Mcp-Session-Id requirement and the DNS-rebinding gotcha the docs warn about but most walkthroughs skip.
A runnable LangGraph human-in-the-loop tutorial for 2026: pause an agent mid-run with interrupt(), review the proposed action, then approve, edit, or reject it with Command(resume=...). Includes the checkpointer requirement and the re-run-from-the-top gotcha that breaks most tutorials.
A runnable 2026 tutorial: build a write-capable MCP server in Python with FastMCP and the official MCP SDK. Add tools with @mcp.tool(), back them with SQLite, test in the Inspector, and connect it to Claude for Desktop.
A runnable 2026 tutorial: give an AI agent web search in Python with the Claude web_search server tool. Read citations, cap cost with max_uses, filter domains, and go multi turn.
A hands-on LangGraph tutorial for 2026: build the same tool-using AI agent two ways, with the five-line create_agent helper and as an explicit StateGraph you can customize. Fully runnable Python.
The five parts every AI agent has, a runnable Python example in about 40 lines, and an honest guide to the guardrails and framework choices most tutorials skip.
A runnable 2026 guide to custom tools in the Claude Agent SDK: define functions with tool() / @tool, bundle them into an in-process MCP server, register with allowedTools, and gate risky calls per argument with canUseTool. TypeScript and Python.
A runnable comparison of the Claude Agent SDK and LangGraph in 2026, with the same agent built in both and an honest decision matrix for when each wins.
Make a Claude turn survive a browser reload: server-side ring buffer keyed by message.id, the WHATWG Last-Event-ID header, and a Next.js App Router Route Handler that replays missed SSE frames in 180 ms. Measured June 2026 on claude-sonnet-4-6.