MULTIPLE_SUBGRAPHS

This error occurs when you call a subgraph inside a node (opens in a new tab) multiple times, and the subgraph is compiled with checkpointer=True (continuations mode).

Troubleshooting

Choose one of the following based on your requirements:

1. Don't need interrupts? Use checkpointer=False to opt out of checkpointing entirely:

   subgraph = subgraph_builder.compile(checkpointer=False)

2. Need interrupts but not cross-invocation persistence? Use the default inherited mode by omitting checkpointer:

   subgraph = subgraph_builder.compile()

   Each invocation gets a unique namespace, so parallel execution works. The subgraph starts fresh each time but can use interrupt().

3. Need cross-invocation persistence? Use checkpointer=True. LangGraph assigns each invocation a position-based namespace suffix (calling_node, calling_node|1, etc.) to prevent conflicts. For stable, name-based namespaces, wrap each subgraph with a unique node name — see parallel subgraphs (opens in a new tab).

Related

• Subgraph persistence (opens in a new tab) — full comparison of checkpointer modes
• Persistence (opens in a new tab) — how checkpointers work in LangGraph