diff --git a/AGENTS.md b/AGENTS.md
index 6bf4eb5f..7908fdcd 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -186,6 +186,7 @@ Multi-level confidence scheme allows users to control which providers see which
 
 - **File changes require Write/Edit tools** - Never use bash commands like `cat <<EOF` or `echo >`
 - **End of file formatting** - Do not append an extra empty line at the end of files.
+- **No automated formatting for Rust or .NET files** - Never run automated formatters on Rust files (`.rs`) or .NET files (`.cs`, `.razor`, `.csproj`, etc.). Only make the minimal manual formatting changes required for the specific edit.
 - **Spaces in paths** - Always quote paths with spaces in bash commands
 - **Agent-run .NET builds** - Do not run `.NET` builds from an agent. Ask the user to run the build locally in their IDE, preferably via `cd app/Build && dotnet run build` in an IDE terminal, then wait for their feedback before continuing.
 - **Debug environment** - Reads `startup.env` file with IPC credentials