diff --git a/AGENTS.md b/AGENTS.md
index 8978606..85ed358 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -60,7 +60,7 @@ Use these commands to perform common development tasks:
 ## Code Style and Conventions
 
 * Follow standard C# naming conventions (PascalCase for classes/methods/properties, camelCase for local variables).
-* Use nullable reference types (`#nullable enable`).
+* Nullable reference types are enabled at the project level (`<Nullable>enable</Nullable>` in .csproj files). Do not use file-level `#nullable enable` directives.
 * Warnings are treated as errors (`<TreatWarningsAsErrors>true</TreatWarningsAsErrors>`).
 * Avoid public fields; prefer properties.