diff --git a/proposals/filesystem/wit-0.3.0-draft/types.wit b/proposals/filesystem/wit-0.3.0-draft/types.wit
index 141072bdb..102f663e9 100644
--- a/proposals/filesystem/wit-0.3.0-draft/types.wit
+++ b/proposals/filesystem/wit-0.3.0-draft/types.wit
@@ -582,8 +582,11 @@ interface types {
 
         /// Unlink a filesystem object that is not a directory.
         ///
-        /// Return `error-code::is-directory` if the path refers to a directory.
-        /// Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
+        /// This is similar to `unlinkat(fd, path, 0)` in POSIX.
+        ///
+        /// Error returns are as specified by POSIX, with the exception that any
+        /// `error-code::access` return is instead replaced with
+        /// `error-code::not-permitted`.
         @since(version = 0.3.0-rc-2025-09-16)
         unlink-file-at: async func(
             /// The relative path to a file to unlink.