diff --git a/.changeset/26619-action-keys-disabled-reason.md b/.changeset/26619-action-keys-disabled-reason.md
new file mode 100644
index 00000000000..e1de2c18216
--- /dev/null
+++ b/.changeset/26619-action-keys-disabled-reason.md
@@ -0,0 +1,8 @@
+---
+'@object-ui/core': patch
+---
+
+`SPEC_ACTION_KEYS` lists `disabledReason`, the key `@objectstack/spec` added to `ActionSchema` beside `disabled` (objectstack#26786). An action that carries it is no longer counted as having an unknown key, and the inventory pin is green again.
+
+Clause-②: no
+Metadata-protocol: none
diff --git a/ui/packages/core/src/actions/actionKeys.ts b/ui/packages/core/src/actions/actionKeys.ts
index 9184acb74c2..100c1f5a63c 100644
--- a/ui/packages/core/src/actions/actionKeys.ts
+++ b/ui/packages/core/src/actions/actionKeys.ts
@@ -246,6 +246,7 @@ export const SPEC_ACTION_KEYS = [
   // key, which is the only thing the inventory is consulted for.
   'description',
   'disabled',
+  'disabledReason',
   'errorMessage',
   // No `execute`: its spec-17 tombstone (`retiredKey()`, objectstack#3855) aged
   // out of `ActionSchema` at objectstack#25767 — the spec now refuses it as an