feat(llm): detect whether a model accepts image input (#1460)

* feat(llm): detect whether a model accepts image input

Add model_supports_images(): OpenRouter models are checked against architecture.input_modalities from OpenRouter's public model list (fetched once per process), others against LiteLLM's supports_vision. Unknown models and lookup failures count as image-capable. Not wired in yet.

* refactor(llm): read image support from litellm's catalog, assuming it for unknown models

* style: drop a trailing space in the image-support docstring

strix/config/models.py

@@ -905,6 +905,12 @@ def model_supports_reasoning(model_name: str) -> bool:
     return bool(entry and entry.get("supports_reasoning"))
 
 
+def model_supports_images(model_name: str) -> bool:
+    """Return whether the model accepts image input. Assume yes until proven otherwise."""
+    entry = _catalog_entry(model_name)
+    return entry is None or bool(entry.get("supports_vision"))
+
+
 def _bare_openai_name(model_name: str) -> str:
     name = model_name.strip().lower()
     for prefix in ("litellm/", "any-llm/", "openai/"):

tests/test_models.py

@@ -16,6 +16,7 @@ from strix.config.models import (
     _NonStreamingModel,
     _TurnGuardModel,
     configure_sdk_model_defaults,
+    model_supports_images,
     request_timeout_extra_args,
     resolve_api_type,
     routes_through_litellm,
@@ -202,3 +203,11 @@ def test_configure_sdk_api_route_follows_the_given_model(
     models.configure_sdk_api_route("my-private-model", settings)
 
     assert routes == ["responses", "chat_completions"]
+
+
+def test_image_support_follows_the_catalog(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setitem(litellm.model_cost, "acme-text", {})
+    monkeypatch.setitem(litellm.model_cost, "acme-vision", {"supports_vision": True})
+    assert model_supports_images("acme-text") is False
+    assert model_supports_images("litellm/openai/acme-vision") is True
+    assert model_supports_images("acme-unknown-model") is True