Clarification Needed: Configuration requirements (Snapshot vs Full) for resuming LangGraph with Command after interrupt

[Usamsa]

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Example Code

h// Example: Using only checkpoint info
const checkpointConfig = { configurable: { thread_id: '...', checkpoint_id: '...' } };
await graph.invoke(new Command({ resume: humanInput }), checkpointConfig);

// Example: Merging original config with checkpoint info
const originalAppConfig = { configurable: { thread_id: 'initial_or_irrelevant', llm: myLlm, availableAgents: [...] /*, other app data */ } };
const checkpointConfig = { configurable: { thread_id: 'correct_thread', checkpoint_id: 'correct_checkpoint' } };

const mergedConfig = {
    ...originalAppConfig, // Keep runName, callbacks etc. if needed
    configurable: {
        ...originalAppConfig.configurable, // Keep app data like llm, availableAgents
        // Overwrite with necessary checkpoint details
        thread_id: checkpointConfig.configurable.thread_id,
        checkpoint_id: checkpointConfig.configurable.checkpoint_id,
        checkpoint_ns: checkpointConfig.configurable.checkpoint_ns ?? '',
    }
};
await graph.invoke(new Command({ resume: humanInput }), mergedConfig);

Description

@dosu

I am implementing a human-in-the-loop workflow in LangGraph (JavaScript/TypeScript) using the interrupt() function within a graph node. The graph execution pauses as expected. I am retrieving the state snapshot (including snapshot.config which contains { configurable: { thread_id, checkpoint_id, ... } }) either via graph.getState(config) or from the interrupt event payload when using streamEvents.
Execution is then resumed later using graph.invoke(new Command({ resume: humanInput }), resumeConfig) or graph.streamEvents(new Command({ resume: humanInput }), resumeConfig).
Problem/Question:
There appears to be ambiguity or missing detail in the documentation regarding the exact requirements for the resumeConfig object passed during the resume call. Specifically:
Is it sufficient to pass only the checkpointing configuration obtained from the snapshot (i.e., resumeConfig = snapshot.config)?

Or, is it necessary to pass the full original RunnableConfig (including application-specific details like LLM instances, tool definitions, availableAgents, custom parameters passed during the initial run, etc.) merged with the essential checkpointing information (thread_id, checkpoint_id) from the snapshot?

System Info

mac

@langchain/openai: >=0.1.0 <0.5.0
js-yaml: ^4.1.0
openapi-types: ^12.1.3
yaml: ^2.2.1
@langchain/textsplitters: >=0.0.0 <0.2.0 jsonpointer: ^5.0.1
p-retry: 4
zod-to-json-schema: ^3.22.3
js-tiktoken: ^1.0.12
langsmith: >=0.2.8 <0.4.0
uuid: ^10.0.0
zod: ^3.22.4

[dosubot[bot]]

The LangChain documentation does not provide specific details on whether the resumeConfig object should consist solely of checkpointing configuration or if it needs to be merged with the full original RunnableConfig. However, based on best practices for handling interruptions and resuming execution in LangGraph, it is generally advisable to merge the original configuration with checkpoint information to ensure that all necessary application-specific details are preserved during the resume process.

This approach allows you to maintain important runtime values, such as LLM instances, tool definitions, and other custom parameters, while also incorporating essential checkpointing details like thread_id and checkpoint_id. This ensures that the resumed execution has access to all the context and resources it needs to function correctly.

If you encounter issues with resuming execution using only the checkpoint configuration, consider merging it with the original configuration as demonstrated in your example code. This should help maintain the integrity and continuity of your application's workflow.

To continue talking to Dosu, mention @dosu.

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[Usamsa]

@dosu will the entire logic be deleted, if recompile the graph after the interrupt, although i saved the config?

[dosubot[bot]]

Recompiling a graph after an interrupt in LangChain does not inherently delete the entire logic if you have saved the configuration. By using a checkpointer, such as MemorySaver, you can preserve the state and configurations across recompilations. This allows you to maintain the logic and state of your application, including message history and other configurations, ensuring continuity even after recompilation ^[1][2].

To continue talking to Dosu, mention @dosu.

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