fix: flatten nested anyOf/oneOf in Gemini schema cleaning (openclaw#22825) thanks @Oceanswave

Verified:
- pnpm build
- pnpm check
- pnpm test:macmini

Co-authored-by: Oceanswave <760674+Oceanswave@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/agents/schema/clean-for-gemini.ts

@@ -339,9 +339,63 @@ function cleanSchemaForGeminiWithDefs(
     }
   }
 
+  // Cloud Code Assist API rejects anyOf/oneOf in nested schemas even after
+  // simplifyUnionVariants runs above. Flatten remaining unions as a fallback:
+  // pick the common type or use the first variant's type so the tool
+  // declaration is accepted by Google's validation layer.
+  if (cleaned.anyOf && Array.isArray(cleaned.anyOf)) {
+    const flattened = flattenUnionFallback(cleaned, cleaned.anyOf);
+    if (flattened) {
+      return flattened;
+    }
+  }
+  if (cleaned.oneOf && Array.isArray(cleaned.oneOf)) {
+    const flattened = flattenUnionFallback(cleaned, cleaned.oneOf);
+    if (flattened) {
+      return flattened;
+    }
+  }
+
   return cleaned;
 }
 
+/**
+ * Last-resort flattening for anyOf/oneOf arrays that could not be simplified
+ * by `simplifyUnionVariants`. Picks a representative type so the schema is
+ * accepted by Google's restricted JSON Schema validation.
+ */
+function flattenUnionFallback(
+  obj: Record<string, unknown>,
+  variants: unknown[],
+): Record<string, unknown> | undefined {
+  const objects = variants.filter(
+    (v): v is Record<string, unknown> => !!v && typeof v === "object",
+  );
+  if (objects.length === 0) {
+    return undefined;
+  }
+  const types = new Set(objects.map((v) => v.type).filter(Boolean));
+  if (objects.length === 1) {
+    const merged: Record<string, unknown> = { ...objects[0] };
+    copySchemaMeta(obj, merged);
+    return merged;
+  }
+  if (types.size === 1) {
+    const merged: Record<string, unknown> = { type: Array.from(types)[0] };
+    copySchemaMeta(obj, merged);
+    return merged;
+  }
+  const first = objects[0];
+  if (first?.type) {
+    const merged: Record<string, unknown> = { type: first.type };
+    copySchemaMeta(obj, merged);
+    return merged;
+  }
+  const merged: Record<string, unknown> = {};
+  copySchemaMeta(obj, merged);
+  return merged;
+}
+
 export function cleanSchemaForGemini(schema: unknown): unknown {
   if (!schema || typeof schema !== "object") {
     return schema;