How to Use Lists in For Loops
How to transform multi-select values into a usable format in Agent.ai workflows
Overview
When using for loop actions in Agent.ai, you might run into issues if you’re working with multi-select dropdowns. The problem usually comes down to format: for loop expects a very specific type of input, and the raw output from a multi-dropdown list might not be an exact match.
This guide walks you through how to inspect your input, transform it using a built-in LLM, and successfully run a loop with multi-dropdown values.
Required Format for for loop
Agent.ai’s for loop requires a plain list of strings in the following format:
Unspecified
- Must include square brackets []
- Each item must be in quotes
- Items must be separated by commas
Structured JSON (e.g., objects with ) will not work directly.
Step 1: Inspect Multi-Dropdown Output
Multi-dropdown inputs do not return a list of strings. Instead, you’ll get a list of objects that looks like this:
To verify this, add a Create Output action immediately after your multi-dropdown input and display the variable. This lets you confirm the exact format before using it in a loop.
Step 2: Transform the Input
To convert this into a usable format, insert an LLM action before the the loop action. Use a prompt that extracts only the value fields and returns a plain list of strings.
Example Prompt
You will receive a JSON array of objects. Each object has a “label” and “value.”
Your task:
- Extract the “value” from each object
- Return a plain Python list of strings
- No extra text, no code block formatting, no JSON structure
- Only output something like: [“LinkedIn”, “Twitter”]
Step 3: Use the Transformed List
Once the LLM returns the cleaned-up list, pass it into your for loop action. The loop should now work as expected.
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