Why is my Loop Over Items node processing only the first JSON element?

When using the Loop Over Items node in n8n, it expects each item to be a separate JSON object rather than a single object containing an array. It sounds like your LLM is returning one JSON object with a field called "document" that contains an array, and then you're passing that single item to the Loop Over Items node. As a result, the node only sees one item (even though that item is an array), so it processes the first element and then moves to the DONE branch.

To resolve this, you need to split the array into individual items before connecting to the Loop Over Items node. For example, you can add a Code node right after your LLM that transforms the incoming JSON:

JSCopied
// Assuming the incoming JSON is:
// { "document": ["parag1", "parag2", "parag3"] }

const paragraphs = $json.document; // get the array of paragraphs

// Map each paragraph to its own item
return paragraphs.map(paragraph => ({ json: { paragraph } }));

Now, each paragraph is its own item in the workflow. When you then connect these items to the Loop Over Items node with the batch size set to 1, it will correctly run the loop over every paragraph rather than just the first one.

Make sure your workflow is similar to:

1. LLM node outputs a JSON object with "document": [...].
2. Code node splits the document array into separate items.
3. Loop Over Items node iterates over each generated item (each paragraph).

This should fix the issue you’re encountering.