diff --git a/ci/core-ref.json b/ci/core-ref.json
index 358c111..e9ab5f2 100644
--- a/ci/core-ref.json
+++ b/ci/core-ref.json
@@ -1,6 +1,6 @@
 {
   "repo": "https://gitea.whitlocktech.com/RunicGateway/website.git",
-  "branch": "edge",
+  "branch": "main",
   "ref": "4ad8b2bb0ede2747622075dcfa4cb1fe460f91ca",
   "why": [
     "The core this kit is written against, pinned to a commit rather than a branch.",
@@ -15,10 +15,15 @@
     "MODULE_API_VERSION, so a contract bump turns this repo red on purpose",
     "(MODULE_SYSTEM.md 2.11.1 d2, 2.10).",
     "",
-    "The branch is `edge`, not `main`, and that is not a mistake: the module system",
-    "has not cut over yet and core's `main` has no server/src/modules/ at all",
-    "(MODULE_SYSTEM.md decision 11). This pin is one of the things that cutover has",
-    "to revisit.",
+    "The branch said `edge` until 2026-08-12, when the module system cut over",
+    "and that branch was deleted (MODULE_SYSTEM.md 2.9). The SHA DID NOT MOVE:",
+    "the pinned commit is an ancestor of `main`, so this is a label correction",
+    "and not a re-pin - the contract is still 1.5.0 and no chapter changed.",
+    "Nothing in CI reads this field; it clones the repo and checks out the sha,",
+    "which is why the cutover could not break the build and why a wrong label",
+    "here would have sat unnoticed. It is for the person deciding whether a",
+    "newer core is worth re-reading the book for, and a branch that no longer",
+    "exists tells them nothing.",
     "",
     "Same convention as Module-uo's ci/core-ref.json, deliberately - one file, one",
     "sha, reviewable in a diff."
diff --git a/scripts/checkCoreApi.js b/scripts/checkCoreApi.js
index 3b655f4..4304c45 100644
--- a/scripts/checkCoreApi.js
+++ b/scripts/checkCoreApi.js
@@ -43,8 +43,9 @@ const versionFile = path.resolve(corePath, 'server/src/modules/version.js')
 if (!fs.existsSync(versionFile)) {
   console.error(`checkCoreApi: ${versionFile} does not exist.`)
   console.error('  Either --core does not point at a website checkout, or the pin in')
-  console.error('  ci/core-ref.json names a ref with no module system in it (core `main`')
-  console.error('  has none until the cutover — see that file).')
+  console.error('  ci/core-ref.json names a core from before the module system existed')
+  console.error('  (it reached `main` at the 2026-08-12 cutover, so any ref older than')
+  console.error('  that on `main` has no server/src/modules/ at all).')
   process.exit(1)
 }