What script can use to convert batch of WMF file to ai file?

This worked for me.

# Save the updated script with summary reporting as a .jsx file for download
script_with_summary_path = "/mnt/data/BatchConvertWMFtoAI_Summary.jsx"

script_content_with_summary = """\
// Adobe Illustrator Script to Batch Convert WMF to AI
// This script opens .wmf files in a folder, crops them to the artwork bounds, and saves them as .ai files.

// Get folder containing the WMF files
var inputFolder = Folder.selectDialog("Select the folder with WMF files");
if (!inputFolder) {
    alert("No folder selected. Script cancelled.");
    exit();
}

// Get list of .wmf files in the folder
var files = inputFolder.getFiles("*.wmf");
if (files.length === 0) {
    alert("No WMF files found in the selected folder.");
    exit();
}

// Initialize counters for summary
var successfulConversions = 0;
var failedConversions = [];

// Loop through all WMF files
for (var i = 0; i < files.length; i++) {
    var file = files[i];
    var doc;

    try {
        doc = app.open(file); // Open WMF file

        // Crop to artwork bounds
        doc.artboards[0].artboardRect = doc.visibleBounds;

        // Save as AI file
        var saveOptions = new IllustratorSaveOptions();
        saveOptions.compatibility = Compatibility.ILLUSTRATOR17; // Broad compatibility
        saveOptions.compressed = true;
        var outputFile = new File(file.path + "/" + file.name.replace(/\\.wmf$/i, ".ai"));
        doc.saveAs(outputFile, saveOptions);

        successfulConversions++;
    } catch (e) {
        failedConversions.push(file.name + " - " + e.message);
    } finally {
        if (doc) doc.close(SaveOptions.DONOTSAVECHANGES);
    }
}

// Create summary message
var summaryMessage = "Batch conversion complete.\\n\\n" +
                     "Successfully converted: " + successfulConversions + " file(s).\\n";
if (failedConversions.length > 0) {
    summaryMessage += "Failed to convert: " + failedConversions.length + " file(s).\\n\\n";
    summaryMessage += "Errors:\\n" + failedConversions.join("\\n");
}

alert(summaryMessage);
"""

with open(script_with_summary_path, "w") as file:
    file.write(script_content_with_summary)

script_with_summary_path

you should be able to record and action to export to WMF then use Batch to apply such action to a whole folder

but post the script you found to see if we can make it work with the latest ai version