That text form is json which is what a funscript file is, you can validate it with something like https://jsonlint.com
You are also missing a few things to make it into a valid json file.
Here’s a simple 10 sec script with all the information filled out where each second increases the position by 10%
{"actions":[{"at":0,"pos":0},{"at":1000,"pos":10},{"at":2000,"pos":20},{"at":3000,"pos":30},{"at":4000,"pos":40},{"at":5000,"pos":50},{"at":6000,"pos":60},{"at":7000,"pos":70},{"at":8000,"pos":80},{"at":9000,"pos":90},{"at":10000,"pos":100}],"inverted":false,"metadata":{"bookmarks":[{"name":"my bookmark","time":"00:00:04.800"}],"chapters":[{"endTime":"00:00:18.556","name":"my chapter","startTime":"00:00:09.986"}],"creator":"my creator","description":"my description","duration":857,"license":"Free","notes":"my notes","performers":["my performer"],"script_url":"my url","tags":["my tag"],"title":"my title","type":"basic","video_url":"my video url"},"range":100,"version":"1.0"}