fix(xai): route video models by modality

tests/plugins/video_gen/test_xai_plugin.py

@@ -25,6 +25,43 @@ def test_xai_provider_registers():
     assert provider.default_model() == "grok-imagine-video"
 
 
+def test_xai_provider_lists_text_and_current_image_video_models():
+    from plugins.video_gen.xai import XAIVideoGenProvider
+
+    models = XAIVideoGenProvider().list_models()
+    ids = [model["id"] for model in models]
+
+    assert ids[0] == "grok-imagine-video"
+    assert ids[1] == "grok-imagine-video-1.5-preview"
+    assert models[1]["modalities"] == ["image"]
+    assert models[1]["aliases"] == ["grok-imagine-video-1.5-2026-05-30"]
+
+
+def test_xai_routes_default_models_by_modality():
+    from plugins.video_gen.xai import _resolve_model_for_modality
+
+    assert _resolve_model_for_modality(
+        "grok-imagine-video",
+        modality="text",
+        explicit_model=False,
+    ) == "grok-imagine-video"
+    assert _resolve_model_for_modality(
+        "grok-imagine-video",
+        modality="image",
+        explicit_model=False,
+    ) == "grok-imagine-video-1.5-preview"
+    assert _resolve_model_for_modality(
+        "grok-imagine-video-1.5-preview",
+        modality="text",
+        explicit_model=False,
+    ) == "grok-imagine-video"
+    assert _resolve_model_for_modality(
+        "grok-imagine-video-1.5-preview",
+        modality="text",
+        explicit_model=True,
+    ) == "grok-imagine-video-1.5-preview"
+
+
 def test_xai_capabilities_text_and_image_only():
     """xAI was previously advertised with edit/extend operations. The
     simplified surface only exposes text-to-video and image-to-video —

tests/plugins/video_gen/test_xai_plugin_integration.py

@@ -56,7 +56,7 @@ class _FakeAsyncClient:
         return _FakeResponse(200, {
             "status": "done",
             "video": {"url": "https://xai-cdn/out.mp4", "duration": 8},
-            "model": "grok-imagine-video",
+            "model": self.posts[-1]["json"]["model"],
         })
 
 
@@ -113,6 +113,7 @@ class TestXAIPayload:
         provider, captured = xai_provider
         provider.generate("a dog at sunset")
         payload = _last_post(captured)["json"]
+        assert payload["model"] == "grok-imagine-video"
         assert payload["prompt"] == "a dog at sunset"
         assert "image" not in payload
         assert "reference_images" not in payload
@@ -121,8 +122,31 @@ class TestXAIPayload:
         provider, captured = xai_provider
         provider.generate("animate this", image_url="https://example.com/cat.png")
         payload = _last_post(captured)["json"]
+        assert payload["model"] == "grok-imagine-video-1.5-preview"
         assert payload["image"] == {"url": "https://example.com/cat.png"}
 
+    def test_local_image_path_is_sent_as_data_uri(self, xai_provider, tmp_path):
+        provider, captured = xai_provider
+        image_path = tmp_path / "frame.png"
+        image_path.write_bytes(b"\x89PNG\r\n\x1a\nfake")
+
+        provider.generate("animate this", image_url=str(image_path))
+
+        payload = _last_post(captured)["json"]
+        assert payload["model"] == "grok-imagine-video-1.5-preview"
+        assert payload["image"]["url"].startswith("data:image/png;base64,")
+
+    def test_explicit_model_override_is_honored_for_image(self, xai_provider):
+        provider, captured = xai_provider
+        provider.generate(
+            "animate this",
+            image_url="https://example.com/cat.png",
+            model="grok-imagine-video",
+            _model_override_explicit=True,
+        )
+        payload = _last_post(captured)["json"]
+        assert payload["model"] == "grok-imagine-video"
+
     def test_reference_images_payload(self, xai_provider):
         provider, captured = xai_provider
         provider.generate(