refactor: Optimize parameter conversion for get_api_detail func

backend/application/workflow/workflow.go

@@ -3631,7 +3631,25 @@ func toWorkflowAPIParameterAssistType(ty vo.FileSubType) workflow.AssistParamete
 	}
 }
 
+func toVariableSlice(params []*workflow.APIParameter) ([]*vo.Variable, error) {
+	if len(params) == 0 {
+		return nil, nil
+	}
+	res := make([]*vo.Variable, 0, len(params))
+	for _, p := range params {
+		v, err := toVariable(p)
+		if err != nil {
+			return nil, err
+		}
+		res = append(res, v)
+	}
+	return res, nil
+}
+
 func toVariable(p *workflow.APIParameter) (*vo.Variable, error) {
+	if p == nil {
+		return nil, nil
+	}
 	v := &vo.Variable{
 		Name:        p.Name,
 		Description: p.Desc,
@@ -3653,38 +3671,33 @@ func toVariable(p *workflow.APIParameter) (*vo.Variable, error) {
 		v.Type = vo.VariableTypeBoolean
 	case workflow.ParameterType_Array:
 		v.Type = vo.VariableTypeList
-		if len(p.SubParameters) == 1 && p.SubType != nil && *p.SubType != workflow.ParameterType_Object {
-			av, err := toVariable(p.SubParameters[0])
+		if p.SubType == nil {
+			return nil, fmt.Errorf("array parameter '%s' is missing a SubType", p.Name)
+		}
+		// The schema of a list variable is a single variable describing the items.
+		itemSchema := &vo.Variable{
+			Type: vo.VariableType(strings.ToLower(p.SubType.String())),
+		}
+		// If the items in the array are objects, describe their structure.
+		if *p.SubType == workflow.ParameterType_Object {
+			itemFields, err := toVariableSlice(p.SubParameters)
 			if err != nil {
 				return nil, err
 			}
-			v.Schema = &av
+			itemSchema.Schema = itemFields
 		} else {
-			subVs := make([]any, 0)
-			for _, ap := range p.SubParameters {
-				av, err := toVariable(ap)
-				if err != nil {
-					return nil, err
-				}
-				subVs = append(subVs, av)
-			}
-			v.Schema = &vo.Variable{
-				Type:   vo.VariableTypeObject,
-				Schema: subVs,
+			if len(p.SubParameters) > 0 && p.SubParameters[0].AssistType != nil {
+				itemSchema.AssistType = vo.AssistType(*p.SubParameters[0].AssistType)
 			}
 		}
+		v.Schema = itemSchema
 	case workflow.ParameterType_Object:
 		v.Type = vo.VariableTypeObject
-		vs := make([]*vo.Variable, 0)
-		for _, v := range p.SubParameters {
-			objV, err := toVariable(v)
-			if err != nil {
-				return nil, err
-			}
-			vs = append(vs, objV)
-
+		subVars, err := toVariableSlice(p.SubParameters)
+		if err != nil {
+			return nil, err
 		}
-		v.Schema = vs
+		v.Schema = subVars
 	default:
 		return nil, fmt.Errorf("unknown workflow api parameter type: %v", p.Type)
 	}

backend/application/workflow/workflow_test.go

@@ -0,0 +1,158 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package workflow
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/coze-dev/coze-studio/backend/api/model/workflow"
+	"github.com/coze-dev/coze-studio/backend/domain/workflow/entity/vo"
+	"github.com/coze-dev/coze-studio/backend/pkg/lang/ptr"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestToVariable(t *testing.T) {
+	fileAssistType := workflow.AssistParameterType_DEFAULT
+
+	testCases := []struct {
+		name          string
+		input         *workflow.APIParameter
+		expected      *vo.Variable
+		expectErr     bool
+		expectedErrAs any
+	}{
+		{
+			name:     "Nil Input",
+			input:    nil,
+			expected: nil,
+		},
+		{
+			name: "Simple String",
+			input: &workflow.APIParameter{
+				Name: "prompt", Type: workflow.ParameterType_String, IsRequired: true,
+			},
+			expected: &vo.Variable{
+				Name: "prompt", Type: vo.VariableTypeString, Required: true,
+			},
+		},
+		{
+			name: "Simple Object",
+			input: &workflow.APIParameter{
+				Name: "user",
+				Type: workflow.ParameterType_Object,
+				SubParameters: []*workflow.APIParameter{
+					{Name: "name", Type: workflow.ParameterType_String},
+					{Name: "age", Type: workflow.ParameterType_Integer},
+				},
+			},
+			expected: &vo.Variable{
+				Name: "user",
+				Type: vo.VariableTypeObject,
+				Schema: []*vo.Variable{
+					{Name: "name", Type: vo.VariableTypeString},
+					{Name: "age", Type: vo.VariableTypeInteger},
+				},
+			},
+		},
+		{
+			name: "Array of Objects",
+			input: &workflow.APIParameter{
+				Name:    "items",
+				Type:    workflow.ParameterType_Array,
+				SubType: ptr.Of(workflow.ParameterType_Object),
+				SubParameters: []*workflow.APIParameter{
+					{Name: "id", Type: workflow.ParameterType_String},
+					{Name: "price", Type: workflow.ParameterType_Number},
+				},
+			},
+			expected: &vo.Variable{
+				Name: "items",
+				Type: vo.VariableTypeList,
+				Schema: &vo.Variable{
+					Type: vo.VariableTypeObject,
+					Schema: []*vo.Variable{
+						{Name: "id", Type: vo.VariableTypeString},
+						{Name: "price", Type: vo.VariableTypeFloat},
+					},
+				},
+			},
+		},
+		{
+			name: "Array of Primitives (File)",
+			input: &workflow.APIParameter{
+				Name:    "attachments",
+				Type:    workflow.ParameterType_Array,
+				SubType: ptr.Of(workflow.ParameterType_String),
+				SubParameters: []*workflow.APIParameter{
+					{AssistType: &fileAssistType},
+				},
+			},
+			expected: &vo.Variable{
+				Name: "attachments",
+				Type: vo.VariableTypeList,
+				Schema: &vo.Variable{
+					Type:       vo.VariableTypeString,
+					AssistType: vo.AssistType(fileAssistType),
+				},
+			},
+		},
+		{
+			name: "Array of Primitives (String)",
+			input: &workflow.APIParameter{
+				Name:    "tags",
+				Type:    workflow.ParameterType_Array,
+				SubType: ptr.Of(workflow.ParameterType_String),
+			},
+			expected: &vo.Variable{
+				Name: "tags",
+				Type: vo.VariableTypeList,
+				Schema: &vo.Variable{
+					Type: vo.VariableTypeString,
+				},
+			},
+		},
+		{
+			name: "Array with missing SubType",
+			input: &workflow.APIParameter{
+				Name: "bad_array",
+				Type: workflow.ParameterType_Array,
+			},
+			expectErr:     true,
+			expectedErrAs: "missing a SubType",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual, err := toVariable(tc.input)
+
+			if tc.expectErr {
+				require.Error(t, err)
+				if tc.expectedErrAs != nil {
+					assert.True(t, strings.Contains(err.Error(), fmt.Sprint(tc.expectedErrAs)))
+				}
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tc.expected, actual)
+		})
+	}
+}

backend/crossdomain/impl/plugin/plugin.go

@@ -571,31 +571,29 @@ func toWorkflowAPIParameter(parameter *common.APIParameter) *workflow3.APIParame
 	if parameter.SubType != nil {
 		p.SubType = ptr.Of(workflow3.ParameterType(*parameter.SubType))
 	}
-
 	if parameter.DefaultParamSource != nil {
 		p.DefaultParamSource = ptr.Of(workflow3.DefaultParamSource(*parameter.DefaultParamSource))
 	}
 	if parameter.AssistType != nil {
 		p.AssistType = ptr.Of(workflow3.AssistParameterType(*parameter.AssistType))
 	}
 
-	// Check if it's an array that needs unwrapping.
+	// Check if it's a specially wrapped array that needs unwrapping.
 	if parameter.Type == common.ParameterType_Array && len(parameter.SubParameters) == 1 && parameter.SubParameters[0].Name == "[Array Item]" {
 		arrayItem := parameter.SubParameters[0]
+		// The actual type of array elements is the type of the "[Array Item]".
 		p.SubType = ptr.Of(workflow3.ParameterType(arrayItem.Type))
-		// If the "[Array Item]" is an object, its sub-parameters become the array's sub-parameters.
+		// If the array elements are objects, their sub-parameters (fields) are lifted up.
 		if arrayItem.Type == common.ParameterType_Object {
 			p.SubParameters = make([]*workflow3.APIParameter, 0, len(arrayItem.SubParameters))
 			for _, subParam := range arrayItem.SubParameters {
 				p.SubParameters = append(p.SubParameters, toWorkflowAPIParameter(subParam))
 			}
 		} else {
-			// The array's SubType is the Type of the "[Array Item]".
 			p.SubParameters = make([]*workflow3.APIParameter, 0, 1)
 			p.SubParameters = append(p.SubParameters, toWorkflowAPIParameter(arrayItem))
-			p.SubParameters[0].Name = "" // Remove the "[Array Item]" name.
 		}
-	} else if len(parameter.SubParameters) > 0 { // A simple object or a non-wrapped array.
+	} else if len(parameter.SubParameters) > 0 {
 		p.SubParameters = make([]*workflow3.APIParameter, 0, len(parameter.SubParameters))
 		for _, subParam := range parameter.SubParameters {
 			p.SubParameters = append(p.SubParameters, toWorkflowAPIParameter(subParam))