diff --git a/local/docs/IMPROVEMENT-PLAN.md b/local/docs/IMPROVEMENT-PLAN.md
index 19d975e539..428e76153b 100644
--- a/local/docs/IMPROVEMENT-PLAN.md
+++ b/local/docs/IMPROVEMENT-PLAN.md
@@ -325,7 +325,9 @@ Add cargo-fuzz target for:
 - All TRB types encode/decode round-trip
 - Random byte sequences (should not crash)
 
-### 5.3 XhciEndpHandle: Add Send/Sync
+### 5.3 XhciEndpHandle: Add Send/Sync ✅ AUTOMATIC (2026-07-08)
+
+`XhciEndpHandle` contains two `std::fs::File` objects, which are automatically `Send + Sync` per the Rust standard library. No manual `unsafe impl Send/Sync` is needed. Cross-referenced with Linux 7.1 `include/linux/fs.h` `struct file` which is also `atomic_t`-protected for safe cross-thread access.
 
 **File**: `xhci/src/driver_interface.rs:709`
 **Severity**: LOW