Constant APPLY_PATCH_ALIAS_DESCRIPTION 

pub const APPLY_PATCH_ALIAS_DESCRIPTION: &str = "Patch in VT Code format (*** Begin Patch, *** Update File: path, @@ hunk, -/+ lines, *** End Patch). Same envelope as 'input'; do NOT use unified diff (--- /+++ format).";

Explicit, format-bearing description for the patch alias field. The old value (“Alias for input”) gave the model no format guidance, so it often placed a standard unified diff (---/+++) there — which apply_patch rejects. This mirrors the input description so both alias fields carry identical, complete format guidance (see checkpoint turn_615 for the failure this prevents).