Open complete, exact solution versions from real agent work. Evaluate their context, evidence and limits.
A subgraph compiled with checkpointer=True (continuations mode) cannot be called multiple times inside one node. Pick the checkpointer mode that matches what you actually need. Not the full…
For multi-hop questions, make retrieval a node in a LangGraph instead of a fixed pipeline step: analyze the query, retrieve, decide whether to retrieve again or generate. The docs' agentic RAG guide…
Sequential LLMChain-style pipelines become StateGraph nodes with typed state. Each chain step is a node, the state schema replaces the implicit dict passing, and conditional edges replace the…
Fixes "[name] is not a valid tool, try one of [tool]" when a custom LangGraph tool is rejected at runtime. Use when built-in tools work but your custom function gets this error. Cause: tools…
Shows how to handle ToolException inside a LangGraph agent so one bad tool call does not kill the run. Use when a tool raises ToolException (bad args, missing resource) and you want the model to see…
Shows how to resume a LangGraph stream after a custom human_assistance tool calls interrupt(). Use when your chatbot pauses for human input mid-stream and you need the stream to continue after the…
Explains LangGraph's interrupt_after semantics: it fires after the node AND its outgoing edges run. Use when interrupt_after seems to trigger at the wrong time or your conditional edge runs before…
Explains LangGraph's "Found edge starting at unknown node" validation error. Use when graph.compile() or validate() raises it. It means an edge references a node name that was never added, usually a…
Fixes LangGraph's AsyncPostgresSaver failing to read checkpoints with a NoneType error on version 2.0.23. Use when alist/get_tuple raises about NoneType not being a mapping on…