How can I fix JSON parsing errors caused by newline characters in AI agent output?

Below is an explanation of the issue and some suggestions for resolving it:

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Issue Explanation

When you see an error like "The 'JSON Output' in item 0 contains invalid JSON" it means that the string you’re passing into JSON mode isn’t a valid JSON document. One common reason is if newline characters (\n) or other special characters aren’t correctly escaped or processed, causing the JSON parser to fail.

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How to Fix

1. Validate the JSON
   Before passing your output to the JSON expression, check if it’s valid using a JSON validator (such as JSONLint). This will help you pinpoint the exact issue in the JSON structure.

2. Escape or Remove Newline Characters
   If you suspect that the newline characters are causing the error, you can modify your expression to replace them. For example, if your field is named "outputText", update your expression like this:

   JSCopied
   {{ $json.outputText.replace(/\n/g, " ") }}

   This expression uses JavaScript’s replace method to substitute newline characters with a space, ensuring the string is more likely to be valid JSON.

3. Ensure Consistent Data Structure
   Another common issue is that the JSON might reference undefined data. Make sure the field you’re referencing always has a value and that no unexpected null or undefined values are present.

4. Check Your Expression Mode
   Verify that you’re using the correct mode (JSON vs. text). If you’re expecting a plain text string that might have newline characters, consider if JSON mode is required or if another parameter mode might be more appropriate.

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By carefully validating the JSON structure and sanitizing the input string (for example, by replacing or escaping newline characters), you should be able to resolve the error and have your JSON expression execute successfully.