fix: polish parameter preprocessing details

apps/api/internal/runner/param_processor.go

@@ -359,15 +359,16 @@ func (contentFilterProcessor) Process(params map[string]any, modelType string, c
 		next := make([]map[string]any, 0, len(content))
 		for index, item := range content {
 			if isImageContent(item) {
+				reason, path, value := imageContentRemovalEvidence(item, modelType, context)
 				context.recordChange(
 					"ContentFilterProcessor",
 					"remove",
 					fmt.Sprintf("content[%d]", index),
 					item,
 					nil,
-					"当前候选模型没有图像参考输入模式，需移除 image_url。",
-					capabilityPath(modelType, ""),
-					capabilityForType(context.modelCapability, modelType),
+					reason,
+					path,
+					value,
 				)
 				continue
 			}
@@ -408,6 +409,38 @@ func (contentFilterProcessor) Process(params map[string]any, modelType string, c
 	return true
 }
 
+func imageContentRemovalEvidence(item map[string]any, modelType string, context *paramProcessContext) (string, string, any) {
+	role := stringFromAny(item["role"])
+	switch role {
+	case "first_frame":
+		return "模型能力未开启首帧输入，已移除 first_frame。", capabilityPath(modelType, "input_first_frame"), map[string]any{
+			"input_first_frame":      capabilityValue(context.modelCapability, modelType, "input_first_frame"),
+			"input_first_last_frame": capabilityValue(context.modelCapability, modelType, "input_first_last_frame"),
+		}
+	case "last_frame":
+		return "模型能力未开启尾帧或首尾帧输入，已移除 last_frame。", capabilityPath(modelType, "input_first_last_frame"), map[string]any{
+			"input_last_frame":            capabilityValue(context.modelCapability, modelType, "input_last_frame"),
+			"input_first_last_frame":      capabilityValue(context.modelCapability, modelType, "input_first_last_frame"),
+			"max_images_for_last_frame":   capabilityValue(context.modelCapability, modelType, "max_images_for_last_frame"),
+			"max_images_for_first_frame":  capabilityValue(context.modelCapability, modelType, "max_images_for_first_frame"),
+			"max_images_for_middle_frame": capabilityValue(context.modelCapability, modelType, "max_images_for_middle_frame"),
+		}
+	case "reference_image":
+		return "模型能力未开启参考图输入，已移除 reference_image。", capabilityPath(modelType, "input_reference_generate_single"), map[string]any{
+			"input_reference_generate_single":   capabilityValue(context.modelCapability, modelType, "input_reference_generate_single"),
+			"input_reference_generate_multiple": capabilityValue(context.modelCapability, modelType, "input_reference_generate_multiple"),
+			"max_images":                        capabilityValue(context.modelCapability, modelType, "max_images"),
+		}
+	default:
+		return "当前模型能力未开启图像输入，已移除 image_url。", capabilityPath(modelType, "input_first_frame"), map[string]any{
+			"input_first_frame":                 capabilityValue(context.modelCapability, modelType, "input_first_frame"),
+			"input_first_last_frame":            capabilityValue(context.modelCapability, modelType, "input_first_last_frame"),
+			"input_reference_generate_single":   capabilityValue(context.modelCapability, modelType, "input_reference_generate_single"),
+			"input_reference_generate_multiple": capabilityValue(context.modelCapability, modelType, "input_reference_generate_multiple"),
+		}
+	}
+}
+
 type inputAudioProcessor struct{}
 
 func (inputAudioProcessor) Name() string { return "InputAudioProcessor" }

apps/api/internal/runner/param_processor_test.go

@@ -180,6 +180,44 @@ func TestParamProcessorVideoCapabilitiesNormalizeAndFilter(t *testing.T) {
 	}
 }
 
+func TestParamProcessorVideoGenerateLogsFirstFrameRemoval(t *testing.T) {
+	body := map[string]any{
+		"model":  "Seedance T2V",
+		"prompt": "animate it",
+		"content": []any{
+			map[string]any{"type": "text", "text": "animate it"},
+			map[string]any{"type": "image_url", "role": "first_frame", "image_url": "https://example.com/first.png"},
+		},
+	}
+	candidate := store.RuntimeModelCandidate{
+		ModelType: "video_generate",
+		Capabilities: map[string]any{
+			"video_generate": map[string]any{
+				"duration_range": []any{3, 12},
+			},
+		},
+	}
+
+	result := preprocessRequestWithLog("videos.generations", body, candidate)
+	for _, item := range contentItems(result.Body["content"]) {
+		if isImageContent(item) {
+			t.Fatalf("first frame image should be removed for video_generate: %+v", result.Body["content"])
+		}
+	}
+	for _, change := range result.Log.Changes {
+		if change.Path == "content[1]" {
+			if change.Reason != "模型能力未开启首帧输入，已移除 first_frame。" {
+				t.Fatalf("unexpected first frame removal reason: %+v", change)
+			}
+			if change.CapabilityPath != "capabilities.video_generate.input_first_frame" {
+				t.Fatalf("unexpected first frame capability path: %+v", change)
+			}
+			return
+		}
+	}
+	t.Fatalf("expected first frame removal log, got %+v", result.Log.Changes)
+}
+
 func TestParamProcessorImageResolutionAndOutputCount(t *testing.T) {
 	body := map[string]any{
 		"model":  "即梦V4.0",