diff --git a/.changeset/20439-hook-condition-expression-row.md b/.changeset/20439-hook-condition-expression-row.md
new file mode 100644
index 00000000000..3c2258a236e
--- /dev/null
+++ b/.changeset/20439-hook-condition-expression-row.md
@@ -0,0 +1,11 @@
+---
+'@objectstack/spec': patch
+---
+
+`hook.form.ts`'s `condition` row now declares `language: 'expression'`, matching the CEL predicate `HookSchema.condition` actually is.
+
+Clause-②: no
+
+The row previously declared `language: 'javascript'` — the same declared language as a real script row (`body.source`) — over a field that is `EvaluatedExpressionInputSchema`, a CEL predicate. A consumer keyed on the row's declared language could not tell the predicate apart from a script. The `helpText` moves from "Optional formula — skip the hook when this evaluates to false" to "CEL predicate — the hook runs only when TRUE", matching the phrasing every sibling predicate row (`field.form.ts` / `object.form.ts`'s `visibleWhen` / `readonlyWhen` / `requiredWhen`, and the formula `expression` row) already uses.
+
+No key is added, removed, narrowed or widened, and no parse verdict changes — `type: 'code'` and `language` are already-declared form-DSL vocabulary. `metadata-form-declared-rows.pin.test.ts` pins the new value, with a control against a sibling predicate row.
diff --git a/packages/platform-objects/src/apps/translations/en.metadata-forms.generated.ts b/packages/platform-objects/src/apps/translations/en.metadata-forms.generated.ts
index ca8d0084293..0ee1119e6e5 100644
--- a/packages/platform-objects/src/apps/translations/en.metadata-forms.generated.ts
+++ b/packages/platform-objects/src/apps/translations/en.metadata-forms.generated.ts
@@ -811,7 +811,7 @@ export const enMetadataForms: NonNullable<TranslationData['metadataForms']> = {
       },
       condition: {
         label: "Condition",
-        helpText: "Optional formula — skip the hook when this evaluates to false"
+        helpText: "CEL predicate — the hook runs only when TRUE"
       },
       retryPolicy: {
         label: "Retry Policy",
diff --git a/packages/spec/src/data/hook.form.ts b/packages/spec/src/data/hook.form.ts
index d39e4a8f01b..2d21c410f54 100644
--- a/packages/spec/src/data/hook.form.ts
+++ b/packages/spec/src/data/hook.form.ts
@@ -74,7 +74,7 @@ export const hookForm = defineForm({
           { label: 'System (elevated)', value: 'system' },
           { label: 'User (triggering user)', value: 'user' },
         ] },
-        { field: 'condition', type: 'code', language: 'javascript', colSpan: 2, helpText: 'Optional formula — skip the hook when this evaluates to false' },
+        { field: 'condition', type: 'code', language: 'expression', colSpan: 2, helpText: 'CEL predicate — the hook runs only when TRUE' },
         {
           field: 'retryPolicy',
           type: 'composite',
diff --git a/packages/spec/src/system/metadata-form-declared-rows.pin.test.ts b/packages/spec/src/system/metadata-form-declared-rows.pin.test.ts
index b13bbc3ffe9..8ffa6100a8b 100644
--- a/packages/spec/src/system/metadata-form-declared-rows.pin.test.ts
+++ b/packages/spec/src/system/metadata-form-declared-rows.pin.test.ts
@@ -48,6 +48,7 @@ type FormEntry = {
   field?: string;
   widget?: string;
   type?: string;
+  language?: string;
   helpText?: string;
   visibleWhen?: string | { dialect?: string; source?: string };
   fields?: FormEntry[];
@@ -168,3 +169,36 @@ describe('declared keys that now have a form row (#19085)', () => {
     expect(row.helpText).toContain('"name"');
   });
 });
+
+/**
+ * **A `type: 'code'` row's `language` must name the slot it actually edits**
+ * (#20439).
+ *
+ * `hook.form.ts`'s `condition` row declared `language: 'javascript'` over
+ * `HookSchema.condition`, which is `EvaluatedExpressionInputSchema` — a CEL
+ * predicate, not a script. Every sibling predicate row (`field.form.ts` /
+ * `object.form.ts`'s `visibleWhen` / `readonlyWhen` / `requiredWhen`, and the
+ * formula `expression` row) already declares `language: 'expression'`; a
+ * consumer keyed on the declared language (objectui#10963's `CodeWidget`
+ * fix) cannot otherwise tell this row apart from a real script row
+ * (`body.source`, `action.source`, both genuinely `'javascript'`).
+ */
+describe('hook.condition declares the CEL predicate language it edits (#20439)', () => {
+  it('hook.condition is a `code` row declaring language: expression, not javascript', () => {
+    const [row, ...extra] = rowFor('hook', 'condition');
+    expect(row, '`condition` is declared by HookSchema; the hook form must offer it').toBeDefined();
+    expect(extra, 'one row only').toEqual([]);
+    expect(row.type).toBe('code');
+    expect(row.language).toBe('expression');
+  });
+
+  it('CONTROL: a sibling predicate row (field.visibleWhen) also declares expression', () => {
+    // Proves the assertion above actually discriminates: run the identical
+    // probe against a row known to already be correct, so a helper that
+    // stopped reading `language` at all would fail here rather than passing
+    // hook.condition vacuously.
+    const [row] = rowFor('field', 'visibleWhen');
+    expect(row.type).toBe('code');
+    expect(row.language).toBe('expression');
+  });
+});