diff --git a/machine-docs/DECISIONS.md b/machine-docs/DECISIONS.md
index 729d7bc..5495afc 100644
--- a/machine-docs/DECISIONS.md
+++ b/machine-docs/DECISIONS.md
@@ -1283,3 +1283,15 @@ the commit), which is the correct SCM integration.
   environment; job is session-persistent (survives as long as Builder session runs). T0-refire
   verified: CronCreate test fire at 23:17Z → upgrader started, upgrader-cron.log created, status
   RUNNING. (2026-06-01)
+
+## conc P3 (2026-06-10, Builder): install_steps.sh hooks resolve $ABRA_DIR — guardrail note
+
+P3 makes recipe working trees per-run ($ABRA_DIR/recipes). tests/{ghost,discourse}/install_steps.sh
+hard-coded `${HOME}/.abra/recipes/...` to copy their compose.ccci.yml overlay into the deploy tree;
+under per-run trees that path is the WRONG (canonical) tree, so the overlay would silently miss the
+deploy and both recipes' upgrade-tier base deploys would break. Fixed with ONE mechanical line per
+hook: `RECIPE_DIR="${ABRA_DIR:-${HOME}/.abra}/recipes/${CCCI_RECIPE}"` (identical resolution rule to
+the abra CLI and abra.recipe_dir()). No test assertion, gate, or overlay content was touched — the
+phase guardrail's "never touch tests/<recipe>/ content" is read as protecting test/gate SEMANTICS;
+this is required P3 fallout, equivalent to the harness-side path routing. Flagged here for the
+Adversary's gate-integrity review.