diff --git a/llm_connect/openrouter.py b/llm_connect/openrouter.py
index 46d9aef..9a7c283 100644
--- a/llm_connect/openrouter.py
+++ b/llm_connect/openrouter.py
@@ -181,12 +181,20 @@ def _merge_model_params(payload: Dict[str, Any], model_params: Dict[str, Any]) -
             except (ValueError, TypeError):
                 schema = None
         if isinstance(schema, dict):
+            # strict=False: OpenAI's strict mode requires additionalProperties
+            # to be false on every object and every property in the required
+            # list. Most application-supplied schemas are not written that
+            # way (the activity-core daily-triage schema, for example, has
+            # neither). With strict=False, OpenRouter still honours the
+            # schema as a soft constraint and the model's output remains
+            # structured. Callers can opt back into strict by including
+            # `strict: true` themselves in a custom `response_format`.
             payload["response_format"] = {
                 "type": "json_schema",
                 "json_schema": {
                     "name": "structured_output",
                     "schema": schema,
-                    "strict": True,
+                    "strict": False,
                 },
             }