feat(chat): 完善 Chat Completions 兼容层

apps/api/internal/clients/helpers.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"math"
 	"net/http"
+	"sort"
 	"strings"
 	"time"
 )
@@ -87,8 +88,11 @@ func decodeOpenAIStreamReader(reader io.Reader, onDelta StreamDelta) (map[string
 	scanner.Buffer(make([]byte, 0, 64*1024), 16*1024*1024)
 	rawLines := make([]string, 0)
 	parts := make([]string, 0)
+	reasoningParts := make([]string, 0)
 	var last map[string]any
 	var usage Usage
+	finishReason := ""
+	toolCalls := map[int]map[string]any{}
 	for scanner.Scan() {
 		rawLine := scanner.Text()
 		rawLines = append(rawLines, rawLine)
@@ -104,13 +108,23 @@ func decodeOpenAIStreamReader(reader io.Reader, onDelta StreamDelta) (map[string
 		if err := json.Unmarshal([]byte(payload), &event); err != nil {
 			continue
 		}
+		event = NormalizeChatCompletionStreamEvent(event)
 		last = event
-		if text := streamEventText(event); text != "" {
+		text := streamEventText(event)
+		reasoningText := streamEventReasoningContent(event)
+		if text != "" {
 			parts = append(parts, text)
-			if onDelta != nil {
-				if err := onDelta(text); err != nil {
-					return nil, true, err
-				}
+		}
+		if reasoningText != "" {
+			reasoningParts = append(reasoningParts, reasoningText)
+		}
+		aggregateStreamToolCalls(event, toolCalls)
+		if reason := streamEventFinishReason(event); reason != "" {
+			finishReason = reason
+		}
+		if onDelta != nil {
+			if err := onDelta(StreamDeltaEvent{Text: text, ReasoningContent: reasoningText, Event: event}); err != nil {
+				return nil, true, err
 			}
 		}
 		if eventUsage := usageFromOpenAI(event); eventUsage.TotalTokens > 0 {
@@ -131,7 +145,7 @@ func decodeOpenAIStreamReader(reader io.Reader, onDelta StreamDelta) (map[string
 		}
 		return out, true, nil
 	}
-	return buildOpenAIStreamResult(last, parts, usage), true, nil
+	return buildOpenAIStreamResult(last, parts, reasoningParts, toolCalls, finishReason, usage), true, nil
 }
 
 func decodeOpenAIStream(raw []byte) (map[string]any, bool) {
@@ -142,22 +156,32 @@ func decodeOpenAIStream(raw []byte) (map[string]any, bool) {
 	return result, ok && err == nil
 }
 
-func buildOpenAIStreamResult(last map[string]any, parts []string, usage Usage) map[string]any {
-	if len(parts) == 0 {
+func buildOpenAIStreamResult(last map[string]any, parts []string, reasoningParts []string, toolCalls map[int]map[string]any, finishReason string, usage Usage) map[string]any {
+	if len(parts) == 0 && len(reasoningParts) == 0 && len(toolCalls) == 0 {
 		return last
 	}
+	message := map[string]any{
+		"role":    "assistant",
+		"content": strings.Join(parts, ""),
+	}
+	if len(reasoningParts) > 0 {
+		message["reasoning_content"] = strings.Join(reasoningParts, "")
+	}
+	if len(toolCalls) > 0 {
+		message["tool_calls"] = sortedStreamToolCalls(toolCalls)
+	}
+	if finishReason == "" {
+		finishReason = "stop"
+	}
 	var out map[string]any
 	out = map[string]any{
 		"id":     stringFromAny(firstPresent(last["id"], "chatcmpl-stream")),
 		"object": "chat.completion",
 		"model":  stringFromAny(last["model"]),
 		"choices": []any{map[string]any{
-			"index": 0,
-			"message": map[string]any{
-				"role":    "assistant",
-				"content": strings.Join(parts, ""),
-			},
-			"finish_reason": "stop",
+			"index":         0,
+			"message":       message,
+			"finish_reason": finishReason,
 		}},
 	}
 	if usage.TotalTokens > 0 {
@@ -170,6 +194,571 @@ func buildOpenAIStreamResult(last map[string]any, parts []string, usage Usage) m
 	return out
 }
 
+// NormalizeChatCompletionRequestBody 将后续请求里的工具调用上下文还原为
+// OpenAI Chat Completions 标准格式，便于再次发送给 OpenAI-compatible 上游。
+func NormalizeChatCompletionRequestBody(body map[string]any) map[string]any {
+	if body == nil {
+		return nil
+	}
+	out := cloneBody(body)
+	messages, ok := out["messages"].([]any)
+	if !ok {
+		return out
+	}
+	normalizedMessages := make([]any, 0, len(messages))
+	for _, rawMessage := range messages {
+		message, ok := rawMessage.(map[string]any)
+		if !ok {
+			normalizedMessages = append(normalizedMessages, rawMessage)
+			continue
+		}
+		copied := cloneMapAny(message)
+		normalizeToolCallsContainer(copied, false)
+		normalizeToolMessageFields(copied)
+		toolMessages, cleanContent, changed := toolResultMessagesFromContent(copied["content"])
+		if changed {
+			if cleanContent != nil && contentHasText(cleanContent) {
+				copied["content"] = cleanContent
+				normalizedMessages = append(normalizedMessages, copied)
+			} else if len(copied) > 1 || copied["role"] != nil {
+				delete(copied, "content")
+				if len(copied) > 1 {
+					normalizedMessages = append(normalizedMessages, copied)
+				}
+			}
+			normalizedMessages = append(normalizedMessages, toolMessages...)
+			continue
+		}
+		normalizedMessages = append(normalizedMessages, copied)
+	}
+	out["messages"] = normalizedMessages
+	return out
+}
+
+func cloneMapAny(source map[string]any) map[string]any {
+	if source == nil {
+		return nil
+	}
+	out := make(map[string]any, len(source))
+	for key, value := range source {
+		out[key] = value
+	}
+	return out
+}
+
+// NormalizeChatCompletionResult 将供应商自定义推理字段归一化到
+// message.reasoning_content，并从最终回答 content 中剥离内联推理块。
+// 加密推理载荷不可展示，且不应作为正文输出，因此会被忽略。
+func NormalizeChatCompletionResult(result map[string]any) map[string]any {
+	if result == nil {
+		return nil
+	}
+	choices, _ := result["choices"].([]any)
+	for _, rawChoice := range choices {
+		choice, _ := rawChoice.(map[string]any)
+		if message, ok := choice["message"].(map[string]any); ok {
+			normalizeToolCallsContainer(message, false)
+			normalizeReasoningContainer(message, false)
+		}
+		if delta, ok := choice["delta"].(map[string]any); ok {
+			normalizeToolCallsContainer(delta, true)
+			normalizeReasoningContainer(delta, true)
+		}
+	}
+	return result
+}
+
+// NormalizeChatCompletionStreamEvent 将供应商自定义流式推理字段
+// （例如 reasoning_details 或 reasoning）归一化到 delta.reasoning_content。
+func NormalizeChatCompletionStreamEvent(event map[string]any) map[string]any {
+	if event == nil {
+		return nil
+	}
+	choices, _ := event["choices"].([]any)
+	for _, rawChoice := range choices {
+		choice, _ := rawChoice.(map[string]any)
+		if delta, ok := choice["delta"].(map[string]any); ok {
+			normalizeToolCallsContainer(delta, true)
+			normalizeReasoningContainer(delta, true)
+		}
+		if message, ok := choice["message"].(map[string]any); ok {
+			normalizeToolCallsContainer(message, false)
+			normalizeReasoningContainer(message, false)
+		}
+	}
+	return event
+}
+
+func normalizeToolCallsContainer(container map[string]any, stream bool) {
+	if container == nil {
+		return
+	}
+	toolCalls := make([]any, 0)
+	for _, rawToolCall := range rawToolCallValues(container) {
+		for _, normalized := range normalizeRawToolCalls(rawToolCall, len(toolCalls), stream) {
+			toolCalls = append(toolCalls, normalized)
+		}
+	}
+	if contentToolCalls, cleanContent, changed := toolCallsFromContent(container["content"], len(toolCalls), stream); changed {
+		toolCalls = append(toolCalls, contentToolCalls...)
+		setNormalizedContent(container, cleanContent, stream)
+	}
+	if partToolCalls := toolCallsFromParts(container["parts"], len(toolCalls), stream); len(partToolCalls) > 0 {
+		toolCalls = append(toolCalls, partToolCalls...)
+		delete(container, "parts")
+	}
+	if len(toolCalls) > 0 {
+		container["tool_calls"] = toolCalls
+	}
+	for _, key := range []string{"tool_call", "toolCall", "toolCalls", "function_call", "functionCall"} {
+		delete(container, key)
+	}
+}
+
+func normalizeToolMessageFields(message map[string]any) {
+	if message == nil {
+		return
+	}
+	if id := firstNonEmptyString(message["tool_call_id"], message["toolCallId"], message["tool_use_id"], message["toolUseId"], message["call_id"], message["callId"]); id != "" {
+		message["tool_call_id"] = id
+	}
+	for _, key := range []string{"toolCallId", "tool_use_id", "toolUseId", "call_id", "callId"} {
+		delete(message, key)
+	}
+}
+
+func toolResultMessagesFromContent(value any) ([]any, any, bool) {
+	blocks, ok := value.([]any)
+	if !ok {
+		return nil, nil, false
+	}
+	toolMessages := make([]any, 0)
+	remaining := make([]any, 0, len(blocks))
+	for _, rawBlock := range blocks {
+		block, _ := rawBlock.(map[string]any)
+		if len(block) == 0 || stringFromAny(block["type"]) != "tool_result" {
+			remaining = append(remaining, rawBlock)
+			continue
+		}
+		message := map[string]any{
+			"role":         "tool",
+			"tool_call_id": firstNonEmptyString(block["tool_call_id"], block["toolCallId"], block["tool_use_id"], block["toolUseId"], block["id"]),
+			"content":      toolResultContent(block["content"]),
+		}
+		toolMessages = append(toolMessages, message)
+	}
+	if len(toolMessages) == 0 {
+		return nil, nil, false
+	}
+	return toolMessages, contentBlocksText(remaining), true
+}
+
+func toolResultContent(value any) any {
+	if text, ok := value.(string); ok {
+		return text
+	}
+	return jsonStringFromAny(value)
+}
+
+func contentHasText(value any) bool {
+	switch typed := value.(type) {
+	case string:
+		return strings.TrimSpace(typed) != ""
+	case []any:
+		return len(typed) > 0
+	default:
+		return value != nil
+	}
+}
+
+func rawToolCallValues(container map[string]any) []any {
+	values := make([]any, 0, 6)
+	for _, key := range []string{"tool_calls", "tool_call", "toolCalls", "toolCall", "function_call", "functionCall"} {
+		if value, ok := container[key]; ok {
+			values = append(values, value)
+		}
+	}
+	return values
+}
+
+func normalizeRawToolCalls(value any, startIndex int, stream bool) []any {
+	switch typed := value.(type) {
+	case []any:
+		out := make([]any, 0, len(typed))
+		for _, raw := range typed {
+			if toolCall := normalizeToolCall(raw, startIndex+len(out), stream); toolCall != nil {
+				out = append(out, toolCall)
+			}
+		}
+		return out
+	default:
+		if toolCall := normalizeToolCall(value, startIndex, stream); toolCall != nil {
+			return []any{toolCall}
+		}
+		return nil
+	}
+}
+
+func normalizeToolCall(value any, index int, stream bool) map[string]any {
+	source, _ := value.(map[string]any)
+	if len(source) == 0 {
+		return nil
+	}
+	functionSource := mapFromAny(source["function"])
+	if len(functionSource) == 0 {
+		functionSource = mapFromAny(firstPresent(source["function_call"], source["functionCall"]))
+	}
+	name := firstNonEmptyString(
+		functionSource["name"], source["name"], source["function_name"], source["functionName"], source["tool_name"], source["toolName"],
+	)
+	arguments, hasArguments := toolCallArguments(functionSource)
+	if !hasArguments {
+		arguments, hasArguments = toolCallArguments(source)
+	}
+	if name == "" && !hasArguments && firstNonEmptyString(source["id"], source["call_id"], source["callId"], source["tool_call_id"], source["toolCallId"]) == "" {
+		return nil
+	}
+	function := map[string]any{}
+	if name != "" {
+		function["name"] = name
+	}
+	if hasArguments {
+		function["arguments"] = arguments
+	}
+	toolCall := map[string]any{
+		"type":     firstNonEmptyString(source["type"], "function"),
+		"function": function,
+	}
+	if id := firstNonEmptyString(source["id"], source["call_id"], source["callId"], source["tool_call_id"], source["toolCallId"]); id != "" {
+		toolCall["id"] = id
+	} else if !stream {
+		toolCall["id"] = fmt.Sprintf("call_%d", index)
+	}
+	if stream {
+		if rawIndex, ok := firstPresent(source["index"], source["idx"]).(float64); ok {
+			toolCall["index"] = int(math.Round(rawIndex))
+		} else if rawIndex, ok := firstPresent(source["index"], source["idx"]).(int); ok {
+			toolCall["index"] = rawIndex
+		} else {
+			toolCall["index"] = index
+		}
+	}
+	return toolCall
+}
+
+func toolCallsFromContent(value any, startIndex int, stream bool) ([]any, any, bool) {
+	blocks, ok := value.([]any)
+	if !ok {
+		return nil, nil, false
+	}
+	toolCalls := make([]any, 0)
+	remaining := make([]any, 0, len(blocks))
+	containsReasoning := false
+	for _, rawBlock := range blocks {
+		block, _ := rawBlock.(map[string]any)
+		if len(block) == 0 {
+			remaining = append(remaining, rawBlock)
+			continue
+		}
+		switch stringFromAny(block["type"]) {
+		case "tool_use":
+			if toolCall := normalizeToolUseBlock(block, startIndex+len(toolCalls), stream); toolCall != nil {
+				toolCalls = append(toolCalls, toolCall)
+			}
+		case "tool_result":
+			remaining = append(remaining, rawBlock)
+		default:
+			if isReasoningContentBlock(block) {
+				containsReasoning = true
+			}
+			remaining = append(remaining, rawBlock)
+		}
+	}
+	if len(toolCalls) == 0 {
+		return nil, nil, false
+	}
+	if containsReasoning {
+		return toolCalls, remaining, true
+	}
+	return toolCalls, contentBlocksText(remaining), true
+}
+
+func normalizeToolUseBlock(block map[string]any, index int, stream bool) map[string]any {
+	toolCall := map[string]any{
+		"type": "function",
+		"function": map[string]any{
+			"name":      stringFromAny(block["name"]),
+			"arguments": jsonStringFromAny(block["input"]),
+		},
+	}
+	if id := firstNonEmptyString(block["id"], block["tool_use_id"], block["toolUseId"]); id != "" {
+		toolCall["id"] = id
+	} else if !stream {
+		toolCall["id"] = fmt.Sprintf("call_%d", index)
+	}
+	if stream {
+		toolCall["index"] = index
+	}
+	return toolCall
+}
+
+func toolCallsFromParts(value any, startIndex int, stream bool) []any {
+	parts, ok := value.([]any)
+	if !ok {
+		return nil
+	}
+	out := make([]any, 0)
+	for _, rawPart := range parts {
+		part, _ := rawPart.(map[string]any)
+		if functionCall := mapFromAny(firstPresent(part["functionCall"], part["function_call"])); len(functionCall) > 0 {
+			if toolCall := normalizeGeminiFunctionCall(functionCall, startIndex+len(out), stream); toolCall != nil {
+				out = append(out, toolCall)
+			}
+		}
+	}
+	return out
+}
+
+func normalizeGeminiFunctionCall(functionCall map[string]any, index int, stream bool) map[string]any {
+	toolCall := map[string]any{
+		"type": "function",
+		"function": map[string]any{
+			"name":      stringFromAny(functionCall["name"]),
+			"arguments": jsonStringFromAny(firstPresent(functionCall["args"], functionCall["arguments"])),
+		},
+	}
+	if id := firstNonEmptyString(functionCall["id"], functionCall["call_id"], functionCall["callId"]); id != "" {
+		toolCall["id"] = id
+	} else if !stream {
+		toolCall["id"] = fmt.Sprintf("call_%d", index)
+	}
+	if stream {
+		toolCall["index"] = index
+	}
+	return toolCall
+}
+
+func setNormalizedContent(container map[string]any, value any, stream bool) {
+	if text, ok := value.(string); ok && text == "" {
+		if stream {
+			delete(container, "content")
+			return
+		}
+		container["content"] = nil
+		return
+	}
+	container["content"] = value
+}
+
+func isReasoningContentBlock(block map[string]any) bool {
+	switch stringFromAny(block["type"]) {
+	case "thinking", "redacted_thinking", "reasoning.text", "reasoning.summary", "reasoning.encrypted":
+		return true
+	default:
+		return false
+	}
+}
+
+func contentBlocksText(blocks []any) string {
+	parts := make([]string, 0, len(blocks))
+	for _, rawBlock := range blocks {
+		switch block := rawBlock.(type) {
+		case string:
+			parts = append(parts, block)
+		case map[string]any:
+			if text := stringFromAny(firstPresent(block["text"], block["content"])); text != "" {
+				parts = append(parts, text)
+			}
+		}
+	}
+	return strings.Join(parts, "")
+}
+
+func toolCallArguments(source map[string]any) (string, bool) {
+	for _, key := range []string{"arguments", "args", "input", "parameters"} {
+		if value, ok := source[key]; ok {
+			return jsonStringFromAny(value), true
+		}
+	}
+	return "", false
+}
+
+func jsonStringFromAny(value any) string {
+	if value == nil {
+		return ""
+	}
+	if text, ok := value.(string); ok {
+		return text
+	}
+	encoded, err := json.Marshal(value)
+	if err != nil {
+		return ""
+	}
+	return string(encoded)
+}
+
+func normalizeReasoningContainer(container map[string]any, deleteEmptyContent bool) {
+	if container == nil {
+		return
+	}
+	reasoningParts := make([]string, 0, 3)
+	if reasoning := reasoningDetailsText(container["reasoning_details"]); reasoning != "" {
+		reasoningParts = append(reasoningParts, reasoning)
+	} else if reasoning := stringFromAny(container["reasoning_content"]); reasoning != "" {
+		reasoningParts = append(reasoningParts, reasoning)
+	} else if reasoning := stringFromAny(container["reasoning"]); reasoning != "" {
+		reasoningParts = append(reasoningParts, reasoning)
+	}
+	if content, ok := container["content"]; ok {
+		cleanContent, contentReasoning, changed := normalizeReasoningContentValue(content)
+		if changed {
+			if deleteEmptyContent {
+				if text, ok := cleanContent.(string); ok && text == "" {
+					delete(container, "content")
+				} else {
+					container["content"] = cleanContent
+				}
+			} else {
+				container["content"] = cleanContent
+			}
+		}
+		if contentReasoning != "" {
+			reasoningParts = append(reasoningParts, contentReasoning)
+		}
+	}
+	if len(reasoningParts) > 0 {
+		container["reasoning_content"] = strings.Join(reasoningParts, "")
+	}
+	delete(container, "reasoning_details")
+	delete(container, "reasoning")
+}
+
+func reasoningDetailsText(value any) string {
+	rawItems, ok := value.([]any)
+	if !ok {
+		return ""
+	}
+	parts := make([]string, 0, len(rawItems))
+	for _, rawItem := range rawItems {
+		item, _ := rawItem.(map[string]any)
+		switch stringFromAny(item["type"]) {
+		case "reasoning.text":
+			if text := stringFromAny(item["text"]); text != "" {
+				parts = append(parts, text)
+			}
+		case "reasoning.summary":
+			if summary := stringFromAny(item["summary"]); summary != "" {
+				parts = append(parts, summary)
+			}
+		}
+	}
+	return strings.Join(parts, "")
+}
+
+func normalizeReasoningContentValue(value any) (any, string, bool) {
+	switch typed := value.(type) {
+	case string:
+		cleanContent, reasoning, changed := splitTaggedReasoningText(typed)
+		return cleanContent, reasoning, changed
+	case []any:
+		contentParts := make([]string, 0, len(typed))
+		reasoningParts := make([]string, 0)
+		changed := false
+		for _, rawItem := range typed {
+			switch item := rawItem.(type) {
+			case string:
+				contentParts = append(contentParts, item)
+			case map[string]any:
+				switch stringFromAny(item["type"]) {
+				case "thinking":
+					if thinking := stringFromAny(item["thinking"]); thinking != "" {
+						reasoningParts = append(reasoningParts, thinking)
+					}
+					changed = true
+				case "redacted_thinking", "reasoning.encrypted":
+					changed = true
+				case "reasoning.text":
+					if text := stringFromAny(item["text"]); text != "" {
+						reasoningParts = append(reasoningParts, text)
+					}
+					changed = true
+				case "reasoning.summary":
+					if summary := stringFromAny(item["summary"]); summary != "" {
+						reasoningParts = append(reasoningParts, summary)
+					}
+					changed = true
+				case "text", "output_text":
+					if text := stringFromAny(firstPresent(item["text"], item["content"])); text != "" {
+						cleanText, reasoning, tagged := splitTaggedReasoningText(text)
+						contentParts = append(contentParts, cleanText)
+						if reasoning != "" {
+							reasoningParts = append(reasoningParts, reasoning)
+						}
+						changed = changed || tagged
+					}
+				default:
+					if text := stringFromAny(firstPresent(item["text"], item["content"])); text != "" {
+						contentParts = append(contentParts, text)
+					}
+				}
+			}
+		}
+		if !changed {
+			return value, "", false
+		}
+		return strings.Join(contentParts, ""), strings.Join(reasoningParts, ""), true
+	default:
+		return value, "", false
+	}
+}
+
+func splitTaggedReasoningText(text string) (string, string, bool) {
+	lower := strings.ToLower(text)
+	clean := strings.Builder{}
+	reasoning := strings.Builder{}
+	changed := false
+	for offset := 0; offset < len(text); {
+		start, tag := nextReasoningOpenTag(lower, offset)
+		if start < 0 {
+			clean.WriteString(text[offset:])
+			break
+		}
+		clean.WriteString(text[offset:start])
+		openEnd := start + len("<"+tag+">")
+		closeToken := "</" + tag + ">"
+		closeStart := strings.Index(lower[openEnd:], closeToken)
+		if closeStart < 0 {
+			reasoning.WriteString(text[openEnd:])
+			offset = len(text)
+			changed = true
+			break
+		}
+		closeStart += openEnd
+		reasoning.WriteString(text[openEnd:closeStart])
+		offset = closeStart + len(closeToken)
+		changed = true
+	}
+	return clean.String(), reasoning.String(), changed
+}
+
+func nextReasoningOpenTag(lower string, offset int) (int, string) {
+	bestStart := -1
+	bestTag := ""
+	for _, tag := range []string{"think", "reasoning", "analysis"} {
+		needle := "<" + tag + ">"
+		idx := strings.Index(lower[offset:], needle)
+		if idx < 0 {
+			continue
+		}
+		absolute := offset + idx
+		if bestStart < 0 || absolute < bestStart {
+			bestStart = absolute
+			bestTag = tag
+		}
+	}
+	return bestStart, bestTag
+}
+
 func streamEventText(event map[string]any) string {
 	if choices, ok := event["choices"].([]any); ok {
 		for _, rawChoice := range choices {
@@ -195,6 +784,91 @@ func streamEventText(event map[string]any) string {
 	return ""
 }
 
+func streamEventReasoningContent(event map[string]any) string {
+	if choices, ok := event["choices"].([]any); ok {
+		for _, rawChoice := range choices {
+			choice, _ := rawChoice.(map[string]any)
+			if delta, ok := choice["delta"].(map[string]any); ok {
+				if content, ok := delta["reasoning_content"].(string); ok {
+					return content
+				}
+				if content, ok := delta["reasoning"].(string); ok {
+					return content
+				}
+			}
+			if message, ok := choice["message"].(map[string]any); ok {
+				if content, ok := message["reasoning_content"].(string); ok {
+					return content
+				}
+			}
+		}
+	}
+	return ""
+}
+
+func streamEventFinishReason(event map[string]any) string {
+	if choices, ok := event["choices"].([]any); ok {
+		for _, rawChoice := range choices {
+			choice, _ := rawChoice.(map[string]any)
+			if reason, ok := choice["finish_reason"].(string); ok && reason != "" {
+				return reason
+			}
+		}
+	}
+	return ""
+}
+
+func aggregateStreamToolCalls(event map[string]any, toolCalls map[int]map[string]any) {
+	choices, _ := event["choices"].([]any)
+	for _, rawChoice := range choices {
+		choice, _ := rawChoice.(map[string]any)
+		delta, _ := choice["delta"].(map[string]any)
+		rawToolCalls, _ := delta["tool_calls"].([]any)
+		for _, rawToolCall := range rawToolCalls {
+			incoming, _ := rawToolCall.(map[string]any)
+			index := intFromAny(incoming["index"])
+			current := toolCalls[index]
+			if current == nil {
+				current = map[string]any{}
+				toolCalls[index] = current
+			}
+			for _, key := range []string{"id", "type"} {
+				if value, ok := incoming[key].(string); ok && value != "" {
+					current[key] = value
+				}
+			}
+			incomingFn, _ := incoming["function"].(map[string]any)
+			if len(incomingFn) == 0 {
+				continue
+			}
+			currentFn, _ := current["function"].(map[string]any)
+			if currentFn == nil {
+				currentFn = map[string]any{}
+				current["function"] = currentFn
+			}
+			if name, ok := incomingFn["name"].(string); ok && name != "" {
+				currentFn["name"] = stringFromAny(currentFn["name"]) + name
+			}
+			if arguments, ok := incomingFn["arguments"].(string); ok && arguments != "" {
+				currentFn["arguments"] = stringFromAny(currentFn["arguments"]) + arguments
+			}
+		}
+	}
+}
+
+func sortedStreamToolCalls(toolCalls map[int]map[string]any) []any {
+	indices := make([]int, 0, len(toolCalls))
+	for index := range toolCalls {
+		indices = append(indices, index)
+	}
+	sort.Ints(indices)
+	out := make([]any, 0, len(indices))
+	for _, index := range indices {
+		out = append(out, toolCalls[index])
+	}
+	return out
+}
+
 func usageFromOpenAI(result map[string]any) Usage {
 	usage, _ := result["usage"].(map[string]any)
 	input := intFromAny(firstPresent(usage["prompt_tokens"], usage["input_tokens"]))
@@ -254,6 +928,15 @@ func stringFromAny(value any) string {
 	return ""
 }
 
+func firstNonEmptyString(values ...any) string {
+	for _, value := range values {
+		if text := strings.TrimSpace(stringFromAny(value)); text != "" {
+			return text
+		}
+	}
+	return ""
+}
+
 func firstPresent(values ...any) any {
 	for _, value := range values {
 		if value != nil {