pass through model.options properly without having to nest it under provider name. you may have to update your configs see https://opencode.ai/docs/models/#openrouter for an example

opencode.json

@@ -1,5 +1,19 @@
 {
   "$schema": "https://opencode.ai/config.json",
+  "provider": {
+    "openrouter": {
+      "models": {
+        "moonshotai/kimi-k2": {
+          "options": {
+            "provider": {
+              "order": ["baseten"],
+              "allow_fallbacks": false
+            }
+          }
+        }
+      }
+    }
+  },
   "mcp": {
     "weather": {
       "type": "local",