Scripting working spreaders animated tool

Help and Feedback Scripting Support
#1

I have jaws like this
image

and want to script it like
https://gyazo.com/73ef3c5ad01d9200ea4ac2b75e93bd86

https://gyazo.com/5d8f2c86cbbcdb1e64d6a7b3ae4e646f

How would this be done as a tool?