feat(registry): expose generation defaults on selectable models

EvoScientist/model_registry/http_api.py

@@ -171,6 +171,11 @@ class SelectableModel(BaseModel):
     name: str
     provider_name: str
     effective_capabilities: Capabilities
+    # Registry-effective generation defaults (model value wins over the
+    # provider default; both unset -> null). Lets chat UIs anchor their
+    # temperature/top_p sliders without a registry read.
+    default_temperature: float | None = None
+    default_top_p: float | None = None
 
 
 class GetSelectableModelsResponse(BaseModel):
@@ -855,6 +860,16 @@ class ModelRegistryHttpApi:
                     name=model.name,
                     provider_name=provider.name,
                     effective_capabilities=item.effective_capabilities,
+                    default_temperature=(
+                        model.runtime.temperature
+                        if model.runtime.temperature is not None
+                        else provider.runtime.default_temperature
+                    ),
+                    default_top_p=(
+                        model.runtime.top_p
+                        if model.runtime.top_p is not None
+                        else provider.runtime.default_top_p
+                    ),
                 )
             )
         return GetSelectableModelsResponse(models=models, defaults=registry.defaults)

EvoScientist/model_registry/openapi.json

@@ -1178,6 +1178,30 @@
       "SelectableModel": {
         "description": "One entry of the section 9.1 model selector response.",
         "properties": {
+          "default_temperature": {
+            "anyOf": [
+              {
+                "type": "number"
+              },
+              {
+                "type": "null"
+              }
+            ],
+            "default": null,
+            "title": "Default Temperature"
+          },
+          "default_top_p": {
+            "anyOf": [
+              {
+                "type": "number"
+              },
+              {
+                "type": "null"
+              }
+            ],
+            "default": null,
+            "title": "Default Top P"
+          },
           "effective_capabilities": {
             "$ref": "#/components/schemas/Capabilities"
           },

tests/test_model_registry_http.py

@@ -669,6 +669,14 @@ def test_get_models_returns_only_selectable(active_client, store):
         "vision": False,
         "structured_output": True,
     }
+    # Generation defaults ride the catalog so the chat-bar sliders can show
+    # the registry-effective values before any override (model value wins
+    # over the provider default; qwen3 inherits nothing -> null).
+    assert glm["default_temperature"] == 0.7
+    assert glm["default_top_p"] == 0.95
+    qwen = next(m for m in models if m["model_ref"]["model_key"] == "qwen3")
+    assert qwen["default_temperature"] is None
+    assert qwen["default_top_p"] is None
     # The selector echoes the registry defaults so clients can label the
     # `inherit` choice before the first turn.
     assert response.json()["defaults"]["primary"] == {