diff --git a/changelog.d/9731-arena-right-sizing.md b/changelog.d/9731-arena-right-sizing.md
index 78109a41f7..d902f8937e 100644
--- a/changelog.d/9731-arena-right-sizing.md
+++ b/changelog.d/9731-arena-right-sizing.md
@@ -14,7 +14,7 @@ stays disarmed until utilization reaches 70% or capacity grows materially
 into a periodic full-GC loop.
 
 On the compiled Claude Code 2.1.112 workload from the report, arena capacity
-fell from 96.5 MiB before the episode to 36.7 MiB, then 35.7 MiB and 35.7 MiB
-across a five-minute idle soak with about 23 MiB live. RSS fell from 401 MiB at
-the first census to 132 MiB at the last, and exactly one idle full was attributed
+fell from 96.5 MB before the episode to 36.7 MB, then 35.7 MB and 35.7 MB
+across a five-minute idle soak with about 23 MB live. RSS fell from 401 MB at
+the first census to 132 MB at the last, and exactly one idle full was attributed
 to arena right-sizing.
diff --git a/crates/perry-runtime/src/gc/arena_right_size.rs b/crates/perry-runtime/src/gc/arena_right_size.rs
index adcacd15c5..6b892dac61 100644
--- a/crates/perry-runtime/src/gc/arena_right_size.rs
+++ b/crates/perry-runtime/src/gc/arena_right_size.rs
@@ -82,7 +82,7 @@ struct ArenaRightSizeState {
     last_usage: ArenaUsage,
 }
 
-thread_local! {
+crate::perry_thread_local! {
     static STATE: RefCell<ArenaRightSizeState> =
         RefCell::new(ArenaRightSizeState::default());
     #[cfg(test)]