Fixed: #1670

test(translator): add unit tests for OpenAI to Claude requests and tool result handling

- Introduced tests for converting OpenAI requests to Claude with text, base64 images, and URL images in tool results.
- Refactored `convertClaudeToolResultContent` and related functionality to properly handle raw content with images and text.
- Updated conversion logic to streamline image handling for both base64 and URL formats.

internal/translator/claude/openai/chat-completions/claude_openai_request.go

@@ -203,46 +203,9 @@ func ConvertOpenAIRequestToClaude(modelName string, inputRawJSON []byte, stream
 					msg, _ = sjson.SetRaw(msg, "content.-1", part)
 				} else if contentResult.Exists() && contentResult.IsArray() {
 					contentResult.ForEach(func(_, part gjson.Result) bool {
-						partType := part.Get("type").String()
-
-						switch partType {
-						case "text":
-							textPart := `{"type":"text","text":""}`
-							textPart, _ = sjson.Set(textPart, "text", part.Get("text").String())
-							msg, _ = sjson.SetRaw(msg, "content.-1", textPart)
-
-						case "image_url":
-							// Convert OpenAI image format to Claude Code format
-							imageURL := part.Get("image_url.url").String()
-							if strings.HasPrefix(imageURL, "data:") {
-								// Extract base64 data and media type from data URL
-								parts := strings.Split(imageURL, ",")
-								if len(parts) == 2 {
-									mediaTypePart := strings.Split(parts[0], ";")[0]
-									mediaType := strings.TrimPrefix(mediaTypePart, "data:")
-									data := parts[1]
-
-									imagePart := `{"type":"image","source":{"type":"base64","media_type":"","data":""}}`
-									imagePart, _ = sjson.Set(imagePart, "source.media_type", mediaType)
-									imagePart, _ = sjson.Set(imagePart, "source.data", data)
-									msg, _ = sjson.SetRaw(msg, "content.-1", imagePart)
-								}
-							}
-
-						case "file":
-							fileData := part.Get("file.file_data").String()
-							if strings.HasPrefix(fileData, "data:") {
-								semicolonIdx := strings.Index(fileData, ";")
-								commaIdx := strings.Index(fileData, ",")
-								if semicolonIdx != -1 && commaIdx != -1 && commaIdx > semicolonIdx {
-									mediaType := strings.TrimPrefix(fileData[:semicolonIdx], "data:")
-									data := fileData[commaIdx+1:]
-									docPart := `{"type":"document","source":{"type":"base64","media_type":"","data":""}}`
-									docPart, _ = sjson.Set(docPart, "source.media_type", mediaType)
-									docPart, _ = sjson.Set(docPart, "source.data", data)
-									msg, _ = sjson.SetRaw(msg, "content.-1", docPart)
-								}
-							}
+						claudePart := convertOpenAIContentPartToClaudePart(part)
+						if claudePart != "" {
+							msg, _ = sjson.SetRaw(msg, "content.-1", claudePart)
 						}
 						return true
 					})
@@ -291,11 +254,16 @@ func ConvertOpenAIRequestToClaude(modelName string, inputRawJSON []byte, stream
 			case "tool":
 				// Handle tool result messages conversion
 				toolCallID := message.Get("tool_call_id").String()
-				content := message.Get("content").String()
+				toolContentResult := message.Get("content")
 
 				msg := `{"role":"user","content":[{"type":"tool_result","tool_use_id":"","content":""}]}`
 				msg, _ = sjson.Set(msg, "content.0.tool_use_id", toolCallID)
-				msg, _ = sjson.Set(msg, "content.0.content", content)
+				toolResultContent, toolResultContentRaw := convertOpenAIToolResultContent(toolContentResult)
+				if toolResultContentRaw {
+					msg, _ = sjson.SetRaw(msg, "content.0.content", toolResultContent)
+				} else {
+					msg, _ = sjson.Set(msg, "content.0.content", toolResultContent)
+				}
 				out, _ = sjson.SetRaw(out, "messages.-1", msg)
 				messageIndex++
 			}
@@ -358,3 +326,110 @@ func ConvertOpenAIRequestToClaude(modelName string, inputRawJSON []byte, stream
 
 	return []byte(out)
 }
+
+func convertOpenAIContentPartToClaudePart(part gjson.Result) string {
+	switch part.Get("type").String() {
+	case "text":
+		textPart := `{"type":"text","text":""}`
+		textPart, _ = sjson.Set(textPart, "text", part.Get("text").String())
+		return textPart
+
+	case "image_url":
+		return convertOpenAIImageURLToClaudePart(part.Get("image_url.url").String())
+
+	case "file":
+		fileData := part.Get("file.file_data").String()
+		if strings.HasPrefix(fileData, "data:") {
+			semicolonIdx := strings.Index(fileData, ";")
+			commaIdx := strings.Index(fileData, ",")
+			if semicolonIdx != -1 && commaIdx != -1 && commaIdx > semicolonIdx {
+				mediaType := strings.TrimPrefix(fileData[:semicolonIdx], "data:")
+				data := fileData[commaIdx+1:]
+				docPart := `{"type":"document","source":{"type":"base64","media_type":"","data":""}}`
+				docPart, _ = sjson.Set(docPart, "source.media_type", mediaType)
+				docPart, _ = sjson.Set(docPart, "source.data", data)
+				return docPart
+			}
+		}
+	}
+
+	return ""
+}
+
+func convertOpenAIImageURLToClaudePart(imageURL string) string {
+	if imageURL == "" {
+		return ""
+	}
+
+	if strings.HasPrefix(imageURL, "data:") {
+		parts := strings.SplitN(imageURL, ",", 2)
+		if len(parts) != 2 {
+			return ""
+		}
+
+		mediaTypePart := strings.SplitN(parts[0], ";", 2)[0]
+		mediaType := strings.TrimPrefix(mediaTypePart, "data:")
+		if mediaType == "" {
+			mediaType = "application/octet-stream"
+		}
+
+		imagePart := `{"type":"image","source":{"type":"base64","media_type":"","data":""}}`
+		imagePart, _ = sjson.Set(imagePart, "source.media_type", mediaType)
+		imagePart, _ = sjson.Set(imagePart, "source.data", parts[1])
+		return imagePart
+	}
+
+	imagePart := `{"type":"image","source":{"type":"url","url":""}}`
+	imagePart, _ = sjson.Set(imagePart, "source.url", imageURL)
+	return imagePart
+}
+
+func convertOpenAIToolResultContent(content gjson.Result) (string, bool) {
+	if !content.Exists() {
+		return "", false
+	}
+
+	if content.Type == gjson.String {
+		return content.String(), false
+	}
+
+	if content.IsArray() {
+		claudeContent := "[]"
+		partCount := 0
+
+		content.ForEach(func(_, part gjson.Result) bool {
+			if part.Type == gjson.String {
+				textPart := `{"type":"text","text":""}`
+				textPart, _ = sjson.Set(textPart, "text", part.String())
+				claudeContent, _ = sjson.SetRaw(claudeContent, "-1", textPart)
+				partCount++
+				return true
+			}
+
+			claudePart := convertOpenAIContentPartToClaudePart(part)
+			if claudePart != "" {
+				claudeContent, _ = sjson.SetRaw(claudeContent, "-1", claudePart)
+				partCount++
+			}
+			return true
+		})
+
+		if partCount > 0 || len(content.Array()) == 0 {
+			return claudeContent, true
+		}
+
+		return content.Raw, false
+	}
+
+	if content.IsObject() {
+		claudePart := convertOpenAIContentPartToClaudePart(content)
+		if claudePart != "" {
+			claudeContent := "[]"
+			claudeContent, _ = sjson.SetRaw(claudeContent, "-1", claudePart)
+			return claudeContent, true
+		}
+		return content.Raw, false
+	}
+
+	return content.Raw, false
+}

internal/translator/claude/openai/chat-completions/claude_openai_request_test.go

@@ -0,0 +1,137 @@
+package chat_completions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertOpenAIRequestToClaude_ToolResultTextAndBase64Image(t *testing.T) {
+	inputJSON := `{
+		"model": "gpt-4.1",
+		"messages": [
+			{
+				"role": "assistant",
+				"content": "",
+				"tool_calls": [
+					{
+						"id": "call_1",
+						"type": "function",
+						"function": {
+							"name": "do_work",
+							"arguments": "{\"a\":1}"
+						}
+					}
+				]
+			},
+			{
+				"role": "tool",
+				"tool_call_id": "call_1",
+				"content": [
+					{"type": "text", "text": "tool ok"},
+					{
+						"type": "image_url",
+						"image_url": {
+							"url": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUg=="
+						}
+					}
+				]
+			}
+		]
+	}`
+
+	result := ConvertOpenAIRequestToClaude("claude-sonnet-4-5", []byte(inputJSON), false)
+	resultJSON := gjson.ParseBytes(result)
+	messages := resultJSON.Get("messages").Array()
+
+	if len(messages) != 2 {
+		t.Fatalf("Expected 2 messages, got %d. Messages: %s", len(messages), resultJSON.Get("messages").Raw)
+	}
+
+	toolResult := messages[1].Get("content.0")
+	if got := toolResult.Get("type").String(); got != "tool_result" {
+		t.Fatalf("Expected content[0].type %q, got %q", "tool_result", got)
+	}
+	if got := toolResult.Get("tool_use_id").String(); got != "call_1" {
+		t.Fatalf("Expected tool_use_id %q, got %q", "call_1", got)
+	}
+
+	toolContent := toolResult.Get("content")
+	if !toolContent.IsArray() {
+		t.Fatalf("Expected tool_result content array, got %s", toolContent.Raw)
+	}
+	if got := toolContent.Get("0.type").String(); got != "text" {
+		t.Fatalf("Expected first tool_result part type %q, got %q", "text", got)
+	}
+	if got := toolContent.Get("0.text").String(); got != "tool ok" {
+		t.Fatalf("Expected first tool_result part text %q, got %q", "tool ok", got)
+	}
+	if got := toolContent.Get("1.type").String(); got != "image" {
+		t.Fatalf("Expected second tool_result part type %q, got %q", "image", got)
+	}
+	if got := toolContent.Get("1.source.type").String(); got != "base64" {
+		t.Fatalf("Expected image source type %q, got %q", "base64", got)
+	}
+	if got := toolContent.Get("1.source.media_type").String(); got != "image/png" {
+		t.Fatalf("Expected image media type %q, got %q", "image/png", got)
+	}
+	if got := toolContent.Get("1.source.data").String(); got != "iVBORw0KGgoAAAANSUhEUg==" {
+		t.Fatalf("Unexpected base64 image data: %q", got)
+	}
+}
+
+func TestConvertOpenAIRequestToClaude_ToolResultURLImageOnly(t *testing.T) {
+	inputJSON := `{
+		"model": "gpt-4.1",
+		"messages": [
+			{
+				"role": "assistant",
+				"content": "",
+				"tool_calls": [
+					{
+						"id": "call_1",
+						"type": "function",
+						"function": {
+							"name": "do_work",
+							"arguments": "{\"a\":1}"
+						}
+					}
+				]
+			},
+			{
+				"role": "tool",
+				"tool_call_id": "call_1",
+				"content": [
+					{
+						"type": "image_url",
+						"image_url": {
+							"url": "https://example.com/tool.png"
+						}
+					}
+				]
+			}
+		]
+	}`
+
+	result := ConvertOpenAIRequestToClaude("claude-sonnet-4-5", []byte(inputJSON), false)
+	resultJSON := gjson.ParseBytes(result)
+	messages := resultJSON.Get("messages").Array()
+
+	if len(messages) != 2 {
+		t.Fatalf("Expected 2 messages, got %d. Messages: %s", len(messages), resultJSON.Get("messages").Raw)
+	}
+
+	toolContent := messages[1].Get("content.0.content")
+	if !toolContent.IsArray() {
+		t.Fatalf("Expected tool_result content array, got %s", toolContent.Raw)
+	}
+	if got := toolContent.Get("0.type").String(); got != "image" {
+		t.Fatalf("Expected tool_result part type %q, got %q", "image", got)
+	}
+	if got := toolContent.Get("0.source.type").String(); got != "url" {
+		t.Fatalf("Expected image source type %q, got %q", "url", got)
+	}
+	if got := toolContent.Get("0.source.url").String(); got != "https://example.com/tool.png" {
+		t.Fatalf("Unexpected image URL: %q", got)
+	}
+}

internal/translator/openai/claude/openai_claude_request.go

@@ -183,7 +183,12 @@ func ConvertClaudeRequestToOpenAI(modelName string, inputRawJSON []byte, stream
 						// Collect tool_result to emit after the main message (ensures tool results follow tool_calls)
 						toolResultJSON := `{"role":"tool","tool_call_id":"","content":""}`
 						toolResultJSON, _ = sjson.Set(toolResultJSON, "tool_call_id", part.Get("tool_use_id").String())
-						toolResultJSON, _ = sjson.Set(toolResultJSON, "content", convertClaudeToolResultContentToString(part.Get("content")))
+						toolResultContent, toolResultContentRaw := convertClaudeToolResultContent(part.Get("content"))
+						if toolResultContentRaw {
+							toolResultJSON, _ = sjson.SetRaw(toolResultJSON, "content", toolResultContent)
+						} else {
+							toolResultJSON, _ = sjson.Set(toolResultJSON, "content", toolResultContent)
+						}
 						toolResults = append(toolResults, toolResultJSON)
 					}
 					return true
@@ -374,21 +379,41 @@ func convertClaudeContentPart(part gjson.Result) (string, bool) {
 	}
 }
 
-func convertClaudeToolResultContentToString(content gjson.Result) string {
+func convertClaudeToolResultContent(content gjson.Result) (string, bool) {
 	if !content.Exists() {
-		return ""
+		return "", false
 	}
 
 	if content.Type == gjson.String {
-		return content.String()
+		return content.String(), false
 	}
 
 	if content.IsArray() {
 		var parts []string
+		contentJSON := "[]"
+		hasImagePart := false
 		content.ForEach(func(_, item gjson.Result) bool {
 			switch {
 			case item.Type == gjson.String:
-				parts = append(parts, item.String())
+				text := item.String()
+				parts = append(parts, text)
+				textContent := `{"type":"text","text":""}`
+				textContent, _ = sjson.Set(textContent, "text", text)
+				contentJSON, _ = sjson.SetRaw(contentJSON, "-1", textContent)
+			case item.IsObject() && item.Get("type").String() == "text":
+				text := item.Get("text").String()
+				parts = append(parts, text)
+				textContent := `{"type":"text","text":""}`
+				textContent, _ = sjson.Set(textContent, "text", text)
+				contentJSON, _ = sjson.SetRaw(contentJSON, "-1", textContent)
+			case item.IsObject() && item.Get("type").String() == "image":
+				contentItem, ok := convertClaudeContentPart(item)
+				if ok {
+					contentJSON, _ = sjson.SetRaw(contentJSON, "-1", contentItem)
+					hasImagePart = true
+				} else {
+					parts = append(parts, item.Raw)
+				}
 			case item.IsObject() && item.Get("text").Exists() && item.Get("text").Type == gjson.String:
 				parts = append(parts, item.Get("text").String())
 			default:
@@ -397,19 +422,31 @@ func convertClaudeToolResultContentToString(content gjson.Result) string {
 			return true
 		})
 
+		if hasImagePart {
+			return contentJSON, true
+		}
+
 		joined := strings.Join(parts, "\n\n")
 		if strings.TrimSpace(joined) != "" {
-			return joined
+			return joined, false
 		}
-		return content.Raw
+		return content.Raw, false
 	}
 
 	if content.IsObject() {
-		if text := content.Get("text"); text.Exists() && text.Type == gjson.String {
-			return text.String()
+		if content.Get("type").String() == "image" {
+			contentItem, ok := convertClaudeContentPart(content)
+			if ok {
+				contentJSON := "[]"
+				contentJSON, _ = sjson.SetRaw(contentJSON, "-1", contentItem)
+				return contentJSON, true
+			}
 		}
-		return content.Raw
+		if text := content.Get("text"); text.Exists() && text.Type == gjson.String {
+			return text.String(), false
+		}
+		return content.Raw, false
 	}
 
-	return content.Raw
+	return content.Raw, false
 }

internal/translator/openai/claude/openai_claude_request_test.go

@@ -488,6 +488,114 @@ func TestConvertClaudeRequestToOpenAI_ToolResultObjectContent(t *testing.T) {
 	}
 }
 
+func TestConvertClaudeRequestToOpenAI_ToolResultTextAndImageContent(t *testing.T) {
+	inputJSON := `{
+		"model": "claude-3-opus",
+		"messages": [
+			{
+				"role": "assistant",
+				"content": [
+					{"type": "tool_use", "id": "call_1", "name": "do_work", "input": {"a": 1}}
+				]
+			},
+			{
+				"role": "user",
+				"content": [
+					{
+						"type": "tool_result",
+						"tool_use_id": "call_1",
+						"content": [
+							{"type": "text", "text": "tool ok"},
+							{
+								"type": "image",
+								"source": {
+									"type": "base64",
+									"media_type": "image/png",
+									"data": "iVBORw0KGgoAAAANSUhEUg=="
+								}
+							}
+						]
+					}
+				]
+			}
+		]
+	}`
+
+	result := ConvertClaudeRequestToOpenAI("test-model", []byte(inputJSON), false)
+	resultJSON := gjson.ParseBytes(result)
+	messages := resultJSON.Get("messages").Array()
+
+	if len(messages) != 2 {
+		t.Fatalf("Expected 2 messages, got %d. Messages: %s", len(messages), resultJSON.Get("messages").Raw)
+	}
+
+	toolContent := messages[1].Get("content")
+	if !toolContent.IsArray() {
+		t.Fatalf("Expected tool content array, got %s", toolContent.Raw)
+	}
+	if got := toolContent.Get("0.type").String(); got != "text" {
+		t.Fatalf("Expected first tool content type %q, got %q", "text", got)
+	}
+	if got := toolContent.Get("0.text").String(); got != "tool ok" {
+		t.Fatalf("Expected first tool content text %q, got %q", "tool ok", got)
+	}
+	if got := toolContent.Get("1.type").String(); got != "image_url" {
+		t.Fatalf("Expected second tool content type %q, got %q", "image_url", got)
+	}
+	if got := toolContent.Get("1.image_url.url").String(); got != "data:image/png;base64,iVBORw0KGgoAAAANSUhEUg==" {
+		t.Fatalf("Unexpected image_url: %q", got)
+	}
+}
+
+func TestConvertClaudeRequestToOpenAI_ToolResultURLImageOnly(t *testing.T) {
+	inputJSON := `{
+		"model": "claude-3-opus",
+		"messages": [
+			{
+				"role": "assistant",
+				"content": [
+					{"type": "tool_use", "id": "call_1", "name": "do_work", "input": {"a": 1}}
+				]
+			},
+			{
+				"role": "user",
+				"content": [
+					{
+						"type": "tool_result",
+						"tool_use_id": "call_1",
+						"content": {
+							"type": "image",
+							"source": {
+								"type": "url",
+								"url": "https://example.com/tool.png"
+							}
+						}
+					}
+				]
+			}
+		]
+	}`
+
+	result := ConvertClaudeRequestToOpenAI("test-model", []byte(inputJSON), false)
+	resultJSON := gjson.ParseBytes(result)
+	messages := resultJSON.Get("messages").Array()
+
+	if len(messages) != 2 {
+		t.Fatalf("Expected 2 messages, got %d. Messages: %s", len(messages), resultJSON.Get("messages").Raw)
+	}
+
+	toolContent := messages[1].Get("content")
+	if !toolContent.IsArray() {
+		t.Fatalf("Expected tool content array, got %s", toolContent.Raw)
+	}
+	if got := toolContent.Get("0.type").String(); got != "image_url" {
+		t.Fatalf("Expected tool content type %q, got %q", "image_url", got)
+	}
+	if got := toolContent.Get("0.image_url.url").String(); got != "https://example.com/tool.png" {
+		t.Fatalf("Unexpected image_url: %q", got)
+	}
+}
+
 func TestConvertClaudeRequestToOpenAI_AssistantTextToolUseTextOrder(t *testing.T) {
 	inputJSON := `{
 		"model": "claude-3-opus",