Mo. R. Civ. P. 84.20
As amended through May 1, 2024
All motions, briefs, letters, or communications by any party or amicus curiae relating to a matter pending in the court must be addressed to the clerk, who will lay them before the court in due course. Any other letter or communication relating directly or indirectly to any pending matter, addressed to the court or any judge of the court, will not be considered by the court. The clerk may return any such letter or communication to the sender or may refer such letter or communication to the appropriate entity or person.
Mo. R. Civ. P. 84.20