Good checkers for ASD-STE100 are easily available. But, they are for large organizations. For example, for some checkers, you must buy a minimum of 5 licences.
The TechScribe term checker for ASD-STE100 is a result of my search for a good and cost-effective checker for ASD-STE100.
In 1999, I started my freelance career as a technical writer. You can read the story on www.techscribe.co.uk/techw/mike-unwalla.htm. Early in my technical writing career, I learned about AECMA Simplified English (the old name for ASD-STE100) and I started to use the principles in the user guides that I wrote. The AECMA Simplified English specification is large, and to remember all the rules was not easy.
At the ISTC conference (now TCUK) in 2001, someone showed me a checker for a controlled language. Now I wanted a checker for AECMA Simplified English, but all the checkers for AECMA Simplified English were very expensive.
After a long search, and some unsuccessful attempts to find a solution, I found LanguageTool. From that, I developed the term checker. These two articles tell you more:
In 2012, I released the first version of the term checker for ASD-STE100 issue 3 (which is equivalent to AECMA Simplified English issue 2). I continue to improve the term checker. (You can read a summary of the changes in changes.txt.)
All the checkers for controlled language have advantages and disadvantages. My emphasis for the term checker is the grammatical analysis of text. Does a text conform to ASD-STE100? Other checkers have features that the TechScribe term checker does not have. Your task is to find the best software to solve your problems. Read 'How to evaluate software for a controlled language'.
Although I am the only person who writes the rules for the term checker, a team of software developers continues to improve LanguageTool, which is the platform for the term checker. Look at the information on GitHub: https://github.com/languagetool-org/languagetool/graphs/contributors.