diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 62a76a4bc..31d4c882f 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -15,4 +15,5 @@ Below are some of the specific details of various contributions.
 * Jeffrey Phillips Freeman has acted as Lead Developer, daily contributor, and Project Owner.
 * Brent E. Edwards has contributed quality assurance, test coverage, and CI pipeline improvements.
 * HAL 9000 has contributed automated implementation, bug fixes, and feature development as part of the CleverAgents automation pool.
+* HAL 9000 has contributed the plan concurrency race-condition fix (#7989): wired `LockService` into the plan lifecycle, guarding `execute_plan()` and `apply_plan()` with plan-level advisory locks and unique per-invocation owner identities to prevent silent concurrent state corruption.
 * This project was made possible thanks to considerable donation of time, money, and resources by CleverThis, Inc.