It sounds like the beginning of a joke: One lawyer says to the opposing lawyer, “take my word for it…” But it’s actually the beginning of an unenforceable agreement. And not because lawyers are untrustworthy!
To be enforceable, any agreement about any matter in a pending lawsuit must (generally) be in (1) in writing, (2) signed, and (3) filed with the court. An agreement meeting those three requirements is referred to by lawyers as a “Rule 11” or a “Rule 11 Agreement” after Texas Rule of Civil Procedure 11. The text of the rule reads:
Unless otherwise provided in these rules, no agreement between attorneys or parties touching any suit pending will be enforced unless it be in writing, signed and filed with the papers as part of the record, or unless it be made in open court and entered of record.
Above I wrote that it generally has to be in writing. But from the text you can see that an agreement made in open court and entered of record is also enforceable as a Rule 11 Agreement. What’s even more useful is that some courts will enforce agreements made on the record at a deposition, and later filed with the court! So if you can get the other party to agree to terms of a settlement—or even agree to provide you with additional documents—on the record during a deposition, that may be enforceable as a Rule 11.
And here’s another wrinkle: let’s say you sign what you believe to be a Rule 11 Agreement, but it’s about a suit that you haven’t filed yet. That means it’s not really a Rule 11, because the suit isn’t pending. Remember, the text of the rule only relates to pending suits—what then? Even if you don’t have a valid Rule 11, you may still have a valid contract. Of course, contracts are also enforceable by a court, but you’ll probably have to file a lawsuit, first.
So moral of the story? Put everything in writing! It may not seem important, but you never know when someone will conveniently forget what they’ve agreed to do.