fix(config): preserve model overlays across equivalent ids

raven/config/update_providers.py

@@ -967,7 +967,13 @@ def _apply(_text: str | None) -> tuple[str | None, list[str]]:
             # has no parameter to be restated with at all, so a wholesale write
             # loses it every time. Re-adding corrects the tags it names and
             # leaves the rest of the row alone.
-            merged = {**(overlays.get(model) or {}), **overlay}
+            previous = {}
+            target = merge_key(name, model)
+            for stored in list(overlays):
+                if merge_key(name, stored) == target:
+                    # Match the reader's last-row precedence for existing aliases.
+                    previous = overlays.pop(stored) or {}
+            merged = {**previous, **overlay}
             # An empty string is how a caller clears a field it can otherwise
             # only restate; None would be "unstated" and leave it alone.
             merged = {k: v for k, v in merged.items() if v != ""}

tests/test_config_update_providers.py

@@ -1074,6 +1074,60 @@ def test_an_overlay_merges_into_the_row_it_already_had(cfg_path: Path) -> None:
     assert row["capabilities"] == ["reasoning"]
 
 
+@pytest.mark.parametrize(
+    ("existing", "incoming"),
+    [("team-model", "hosted-vllm/team-model"), ("hosted-vllm/team-model", "team-model")],
+)
+@pytest.mark.parametrize(
+    "patch",
+    [{"capabilities": ["reasoning"]}, {"label": ""}, {"capabilities": []}],
+)
+def test_overlay_updates_match_model_identity(cfg_path: Path, existing: str, incoming: str, patch: dict) -> None:
+    original = {"label": "Team model", "description": "Keep this description", "capabilities": ["function-call"]}
+    add_provider_model("hosted_vllm", existing, overlay=original, config_path=cfg_path)
+    add_provider_model("hosted_vllm", "other-model", overlay={"label": "Other model"}, config_path=cfg_path)
+
+    models = add_provider_model("hosted_vllm", incoming, overlay=patch, config_path=cfg_path)
+
+    overlays = _read(cfg_path)["providers"]["hosted_vllm"]["modelOverlay"]
+    assert models == [existing, "other-model"]
+    assert set(overlays) == {incoming, "other-model"}
+    for field, value in (original | patch).items():
+        assert overlays[incoming][field] == value
+    assert overlays["other-model"]["label"] == "Other model"
+
+
+@pytest.mark.parametrize("clear", [False, True])
+def test_overlay_alias_cleanup_preserves_effective_row(cfg_path: Path, clear: bool) -> None:
+    cfg_path.write_text(
+        json.dumps(
+            {
+                "providers": {
+                    "hosted_vllm": {
+                        "models": ["team-model"],
+                        "modelOverlay": {
+                            "hosted-vllm/team-model": {"label": "Stale name", "description": "Stale description"},
+                            "team-model": {"label": "Current name", "description": ""},
+                        },
+                    }
+                }
+            }
+        )
+    )
+
+    patch = {"label": ""} if clear else {"capabilities": ["reasoning"]}
+    add_provider_model("hosted_vllm", "hosted-vllm/team-model", overlay=patch, config_path=cfg_path)
+
+    overlays = _read(cfg_path)["providers"]["hosted_vllm"]["modelOverlay"]
+    if clear:
+        assert overlays == {}
+    else:
+        assert list(overlays) == ["hosted-vllm/team-model"]
+        assert overlays["hosted-vllm/team-model"]["label"] == "Current name"
+        assert overlays["hosted-vllm/team-model"]["description"] == ""
+        assert overlays["hosted-vllm/team-model"]["capabilities"] == ["reasoning"]
+
+
 def test_re_adding_corrects_the_field_it_names(cfg_path: Path) -> None:
     """Merging must not turn a correction into an append: re-adding is how a
     person fixes a tag they got wrong, so a restated field replaces."""

tests/test_rpc_model.py

@@ -2042,3 +2042,25 @@ def no_everos(name: str, *args, **kwargs):
         monkeypatch.setattr(builtins, "__import__", no_everos)
         result = await model_save_key({"slug": "deepseek", "api_key": "new-key"})
         assert result["provider"]["slug"] == "deepseek"
+
+
+async def test_add_model_preserves_metadata_under_a_bare_id(fake_home: Path) -> None:
+    _write_config(
+        fake_home,
+        {
+            "providers": {
+                "hosted_vllm": {
+                    "apiBase": "http://localhost:9999/v1",
+                    "models": ["team-model"],
+                    "modelOverlay": {"team-model": {"label": "Team model", "description": "Keep this description"}},
+                }
+            }
+        },
+    )
+
+    result = await model_add_model({"slug": "hosted_vllm", "model": "team-model", "capabilities": ["reasoning"]})
+
+    row = result["provider"]["model_labels"]["team-model"]
+    assert row["label"] == "Team model"
+    assert row["description"] == "Keep this description"
+    assert row["capabilities"] == ["reasoning"]