You can add Tonemeter to your subscription anytime by logging into the website from a computer or your smartphones interent browser, then go to My Account and click the green button to enable Tonemeter. You can also add Tonemeter to your subscription each time you renew your account.

When using Tonemeter, red bars will appear at the bottom corner of the New Message window to alert you of any emotionally-charged phrase that it has detected. Click those red bars (or the orange box next to those bars when using the website on your computer), and you will see Tonemeters analysis of the phrases in question. If you see no red bars, then Tonemeter has not detected any concerning sentences in your message.

The Tone Meter is an absolute joke. The only purpose it serves, I believe, is as a marketing tool. Think about it: text messages are by far the most difficult messages for HUMANS to understand the tone of, so how on Earth can we expect some app by some rinky-dink company to have developed artificial intelligence sophisticated enough to decipher tone when HUMANS can't even do it? You can review the words and phrases that are flagged in all communications and the "violations" are simply laughable:

"I'm sorry. I misread your text. You're right." - UNSETTLING
"That sounds good, I'm not upset." AGGRESSIVE
"ARE YOU SERIOUS?!?!?!" - (not flagged)

This is snake oil, friends. Do not be fooled. The Tone-Meter is a marketing ploy, and courts are hopping all over it. Whenever a government agency forces you to purchase something from a specific company, you should question what's going on.