diff --git a/.changeset/26849-action-keys-disabled-reason.md b/.changeset/26849-action-keys-disabled-reason.md
new file mode 100644
index 00000000000..dd74f63f26b
--- /dev/null
+++ b/.changeset/26849-action-keys-disabled-reason.md
@@ -0,0 +1,10 @@
+---
+'@object-ui/core': patch
+---
+
+fix(core): the action key inventory lists the spec's `disabledReason`, so an action carrying it is no longer reported as having an unknown key
+
+Clause-②: no
+Metadata-protocol: none
+
+`@objectstack/spec`'s `ActionSchema` declares `disabledReason`, the display-only sentence a greyed action shows to say why. `SPEC_ACTION_KEYS` in `@object-ui/core`, which restates every key that schema declares, did not list it, so the dev-mode unknown-key warning named it on a spec-valid action and the inventory's pin test failed. The entry is added. `ActionDef` is unchanged and nothing in the runner reads the key: its readers ship with the console's disabled-reason work.
diff --git a/ui/packages/core/src/actions/__tests__/actionKeys.pin.test.ts b/ui/packages/core/src/actions/__tests__/actionKeys.pin.test.ts
index 7c560b9c743..5fba66d496c 100644
--- a/ui/packages/core/src/actions/__tests__/actionKeys.pin.test.ts
+++ b/ui/packages/core/src/actions/__tests__/actionKeys.pin.test.ts
@@ -323,5 +323,6 @@ describe('unknown-key warning', () => {
       unknown: ['targt'],
       retired: ['execute'],
     });
+    expect(classifyActionKeys({ type: 'script', disabledReason: 'Closed deals are locked' })).toEqual({ unknown: [], retired: [] });
   });
 });
diff --git a/ui/packages/core/src/actions/actionKeys.ts b/ui/packages/core/src/actions/actionKeys.ts
index 9184acb74c2..e7f884db588 100644
--- a/ui/packages/core/src/actions/actionKeys.ts
+++ b/ui/packages/core/src/actions/actionKeys.ts
@@ -246,6 +246,13 @@ export const SPEC_ACTION_KEYS = [
   // key, which is the only thing the inventory is consulted for.
   'description',
   'disabled',
+  // Added to `ActionSchema` by objectstack#26786: the display-only sentence a
+  // greyed action shows to say why. Listed for the reason `description` is —
+  // this array restates the spec's declared keys, so an action carrying it is
+  // not reported as having an unknown key. `ActionDef` does NOT declare it and
+  // nothing here reads it: its readers ship with the console half of
+  // objectstack#26619.
+  '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