Merge pull request #103 from ChrAlpha/feat/add-gpt-5.2-codex-copilot

feat(openai): responses API support for GitHub Copilot provider

internal/registry/model_definitions.go

@@ -847,6 +847,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/chat/completions", "/responses"},
 		},
 		{
 			ID:                  "gpt-5-mini",
@@ -858,6 +859,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5 Mini via GitHub Copilot",
 			ContextLength:       128000,
 			MaxCompletionTokens: 16384,
+			SupportedEndpoints:  []string{"/chat/completions", "/responses"},
 		},
 		{
 			ID:                  "gpt-5-codex",
@@ -869,6 +871,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5 Codex via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/responses"},
 		},
 		{
 			ID:                  "gpt-5.1",
@@ -880,6 +883,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5.1 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/chat/completions", "/responses"},
 		},
 		{
 			ID:                  "gpt-5.1-codex",
@@ -891,6 +895,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5.1 Codex via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/responses"},
 		},
 		{
 			ID:                  "gpt-5.1-codex-mini",
@@ -902,6 +907,19 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5.1 Codex Mini via GitHub Copilot",
 			ContextLength:       128000,
 			MaxCompletionTokens: 16384,
+			SupportedEndpoints:  []string{"/responses"},
+		},
+		{
+			ID:                  "gpt-5.1-codex-max",
+			Object:              "model",
+			Created:             now,
+			OwnedBy:             "github-copilot",
+			Type:                "github-copilot",
+			DisplayName:         "GPT-5.1 Codex Max",
+			Description:         "OpenAI GPT-5.1 Codex Max via GitHub Copilot",
+			ContextLength:       200000,
+			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/responses"},
 		},
 		{
 			ID:                  "gpt-5.2",
@@ -913,6 +931,19 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "OpenAI GPT-5.2 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/chat/completions", "/responses"},
+		},
+		{
+			ID:                  "gpt-5.2-codex",
+			Object:              "model",
+			Created:             now,
+			OwnedBy:             "github-copilot",
+			Type:                "github-copilot",
+			DisplayName:         "GPT-5.2 Codex",
+			Description:         "OpenAI GPT-5.2 Codex via GitHub Copilot",
+			ContextLength:       200000,
+			MaxCompletionTokens: 32768,
+			SupportedEndpoints:  []string{"/responses"},
 		},
 		{
 			ID:                  "claude-haiku-4.5",
@@ -924,6 +955,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "Anthropic Claude Haiku 4.5 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 64000,
+			SupportedEndpoints:  []string{"/chat/completions"},
 		},
 		{
 			ID:                  "claude-opus-4.1",
@@ -935,6 +967,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "Anthropic Claude Opus 4.1 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 32000,
+			SupportedEndpoints:  []string{"/chat/completions"},
 		},
 		{
 			ID:                  "claude-opus-4.5",
@@ -946,6 +979,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "Anthropic Claude Opus 4.5 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 64000,
+			SupportedEndpoints:  []string{"/chat/completions"},
 		},
 		{
 			ID:                  "claude-sonnet-4",
@@ -957,6 +991,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "Anthropic Claude Sonnet 4 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 64000,
+			SupportedEndpoints:  []string{"/chat/completions"},
 		},
 		{
 			ID:                  "claude-sonnet-4.5",
@@ -968,6 +1003,7 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			Description:         "Anthropic Claude Sonnet 4.5 via GitHub Copilot",
 			ContextLength:       200000,
 			MaxCompletionTokens: 64000,
+			SupportedEndpoints:  []string{"/chat/completions"},
 		},
 		{
 			ID:                  "gemini-2.5-pro",
@@ -981,13 +1017,24 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			MaxCompletionTokens: 65536,
 		},
 		{
-			ID:                  "gemini-3-pro",
+			ID:                  "gemini-3-pro-preview",
 			Object:              "model",
 			Created:             now,
 			OwnedBy:             "github-copilot",
 			Type:                "github-copilot",
-			DisplayName:         "Gemini 3 Pro",
-			Description:         "Google Gemini 3 Pro via GitHub Copilot",
+			DisplayName:         "Gemini 3 Pro (Preview)",
+			Description:         "Google Gemini 3 Pro Preview via GitHub Copilot",
+			ContextLength:       1048576,
+			MaxCompletionTokens: 65536,
+		},
+		{
+			ID:                  "gemini-3-flash-preview",
+			Object:              "model",
+			Created:             now,
+			OwnedBy:             "github-copilot",
+			Type:                "github-copilot",
+			DisplayName:         "Gemini 3 Flash (Preview)",
+			Description:         "Google Gemini 3 Flash Preview via GitHub Copilot",
 			ContextLength:       1048576,
 			MaxCompletionTokens: 65536,
 		},
@@ -1003,15 +1050,16 @@ func GetGitHubCopilotModels() []*ModelInfo {
 			MaxCompletionTokens: 16384,
 		},
 		{
-			ID:                  "raptor-mini",
+			ID:                  "oswe-vscode-prime",
 			Object:              "model",
 			Created:             now,
 			OwnedBy:             "github-copilot",
 			Type:                "github-copilot",
-			DisplayName:         "Raptor Mini",
-			Description:         "Raptor Mini via GitHub Copilot",
+			DisplayName:         "Raptor mini (Preview)",
+			Description:         "Raptor mini via GitHub Copilot",
 			ContextLength:       128000,
 			MaxCompletionTokens: 16384,
+			SupportedEndpoints:  []string{"/chat/completions", "/responses"},
 		},
 	}
 }

internal/registry/model_registry.go

@@ -47,6 +47,8 @@ type ModelInfo struct {
 	MaxCompletionTokens int `json:"max_completion_tokens,omitempty"`
 	// SupportedParameters lists supported parameters
 	SupportedParameters []string `json:"supported_parameters,omitempty"`
+	// SupportedEndpoints lists supported API endpoints (e.g., "/chat/completions", "/responses").
+	SupportedEndpoints []string `json:"supported_endpoints,omitempty"`
 
 	// Thinking holds provider-specific reasoning/thinking budget capabilities.
 	// This is optional and currently used for Gemini thinking budget normalization.
@@ -476,6 +478,9 @@ func cloneModelInfo(model *ModelInfo) *ModelInfo {
 	if len(model.SupportedParameters) > 0 {
 		copyModel.SupportedParameters = append([]string(nil), model.SupportedParameters...)
 	}
+	if len(model.SupportedEndpoints) > 0 {
+		copyModel.SupportedEndpoints = append([]string(nil), model.SupportedEndpoints...)
+	}
 	return &copyModel
 }
 
@@ -988,6 +993,9 @@ func (r *ModelRegistry) convertModelToMap(model *ModelInfo, handlerType string)
 		if len(model.SupportedParameters) > 0 {
 			result["supported_parameters"] = model.SupportedParameters
 		}
+		if len(model.SupportedEndpoints) > 0 {
+			result["supported_endpoints"] = model.SupportedEndpoints
+		}
 		return result
 
 	case "claude", "kiro", "antigravity":

internal/runtime/executor/github_copilot_executor.go

@@ -23,6 +23,7 @@ import (
 const (
 	githubCopilotBaseURL       = "https://api.githubcopilot.com"
 	githubCopilotChatPath      = "/chat/completions"
+	githubCopilotResponsesPath = "/responses"
 	githubCopilotAuthType      = "github-copilot"
 	githubCopilotTokenCacheTTL = 25 * time.Minute
 	// tokenExpiryBuffer is the time before expiry when we should refresh the token.
@@ -106,7 +107,11 @@ func (e *GitHubCopilotExecutor) Execute(ctx context.Context, auth *cliproxyauth.
 	defer reporter.trackFailure(ctx, &err)
 
 	from := opts.SourceFormat
+	useResponses := useGitHubCopilotResponsesEndpoint(from)
 	to := sdktranslator.FromString("openai")
+	if useResponses {
+		to = sdktranslator.FromString("openai-response")
+	}
 	originalPayload := bytes.Clone(req.Payload)
 	if len(opts.OriginalRequest) > 0 {
 		originalPayload = bytes.Clone(opts.OriginalRequest)
@@ -117,7 +122,11 @@ func (e *GitHubCopilotExecutor) Execute(ctx context.Context, auth *cliproxyauth.
 	body = applyPayloadConfigWithRoot(e.cfg, req.Model, to.String(), "", body, originalTranslated)
 	body, _ = sjson.SetBytes(body, "stream", false)
 
-	url := githubCopilotBaseURL + githubCopilotChatPath
+	path := githubCopilotChatPath
+	if useResponses {
+		path = githubCopilotResponsesPath
+	}
+	url := githubCopilotBaseURL + path
 	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
 	if err != nil {
 		return resp, err
@@ -172,6 +181,9 @@ func (e *GitHubCopilotExecutor) Execute(ctx context.Context, auth *cliproxyauth.
 	appendAPIResponseChunk(ctx, e.cfg, data)
 
 	detail := parseOpenAIUsage(data)
+	if useResponses && detail.TotalTokens == 0 {
+		detail = parseOpenAIResponsesUsage(data)
+	}
 	if detail.TotalTokens > 0 {
 		reporter.publish(ctx, detail)
 	}
@@ -194,7 +206,11 @@ func (e *GitHubCopilotExecutor) ExecuteStream(ctx context.Context, auth *cliprox
 	defer reporter.trackFailure(ctx, &err)
 
 	from := opts.SourceFormat
+	useResponses := useGitHubCopilotResponsesEndpoint(from)
 	to := sdktranslator.FromString("openai")
+	if useResponses {
+		to = sdktranslator.FromString("openai-response")
+	}
 	originalPayload := bytes.Clone(req.Payload)
 	if len(opts.OriginalRequest) > 0 {
 		originalPayload = bytes.Clone(opts.OriginalRequest)
@@ -205,9 +221,15 @@ func (e *GitHubCopilotExecutor) ExecuteStream(ctx context.Context, auth *cliprox
 	body = applyPayloadConfigWithRoot(e.cfg, req.Model, to.String(), "", body, originalTranslated)
 	body, _ = sjson.SetBytes(body, "stream", true)
 	// Enable stream options for usage stats in stream
-	body, _ = sjson.SetBytes(body, "stream_options.include_usage", true)
+	if !useResponses {
+		body, _ = sjson.SetBytes(body, "stream_options.include_usage", true)
+	}
 
-	url := githubCopilotBaseURL + githubCopilotChatPath
+	path := githubCopilotChatPath
+	if useResponses {
+		path = githubCopilotResponsesPath
+	}
+	url := githubCopilotBaseURL + path
 	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
 	if err != nil {
 		return nil, err
@@ -283,6 +305,10 @@ func (e *GitHubCopilotExecutor) ExecuteStream(ctx context.Context, auth *cliprox
 				}
 				if detail, ok := parseOpenAIStreamUsage(line); ok {
 					reporter.publish(ctx, detail)
+				} else if useResponses {
+					if detail, ok := parseOpenAIResponsesStreamUsage(line); ok {
+						reporter.publish(ctx, detail)
+					}
 				}
 			}
 
@@ -393,6 +419,10 @@ func (e *GitHubCopilotExecutor) normalizeModel(_ string, body []byte) []byte {
 	return body
 }
 
+func useGitHubCopilotResponsesEndpoint(sourceFormat sdktranslator.Format) bool {
+	return sourceFormat.String() == "openai-response"
+}
+
 // isHTTPSuccess checks if the status code indicates success (2xx).
 func isHTTPSuccess(statusCode int) bool {
 	return statusCode >= 200 && statusCode < 300

internal/runtime/executor/usage_helpers.go

@@ -236,6 +236,44 @@ func parseOpenAIStreamUsage(line []byte) (usage.Detail, bool) {
 	return detail, true
 }
 
+func parseOpenAIResponsesUsageDetail(usageNode gjson.Result) usage.Detail {
+	detail := usage.Detail{
+		InputTokens:  usageNode.Get("input_tokens").Int(),
+		OutputTokens: usageNode.Get("output_tokens").Int(),
+		TotalTokens:  usageNode.Get("total_tokens").Int(),
+	}
+	if detail.TotalTokens == 0 {
+		detail.TotalTokens = detail.InputTokens + detail.OutputTokens
+	}
+	if cached := usageNode.Get("input_tokens_details.cached_tokens"); cached.Exists() {
+		detail.CachedTokens = cached.Int()
+	}
+	if reasoning := usageNode.Get("output_tokens_details.reasoning_tokens"); reasoning.Exists() {
+		detail.ReasoningTokens = reasoning.Int()
+	}
+	return detail
+}
+
+func parseOpenAIResponsesUsage(data []byte) usage.Detail {
+	usageNode := gjson.ParseBytes(data).Get("usage")
+	if !usageNode.Exists() {
+		return usage.Detail{}
+	}
+	return parseOpenAIResponsesUsageDetail(usageNode)
+}
+
+func parseOpenAIResponsesStreamUsage(line []byte) (usage.Detail, bool) {
+	payload := jsonPayload(line)
+	if len(payload) == 0 || !gjson.ValidBytes(payload) {
+		return usage.Detail{}, false
+	}
+	usageNode := gjson.GetBytes(payload, "usage")
+	if !usageNode.Exists() {
+		return usage.Detail{}, false
+	}
+	return parseOpenAIResponsesUsageDetail(usageNode), true
+}
+
 func parseClaudeUsage(data []byte) usage.Detail {
 	usageNode := gjson.ParseBytes(data).Get("usage")
 	if !usageNode.Exists() {

sdk/api/handlers/openai/endpoint_compat.go

@@ -0,0 +1,37 @@
+package openai
+
+import "github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
+
+const (
+	openAIChatEndpoint      = "/chat/completions"
+	openAIResponsesEndpoint = "/responses"
+)
+
+func resolveEndpointOverride(modelName, requestedEndpoint string) (string, bool) {
+	if modelName == "" {
+		return "", false
+	}
+	info := registry.GetGlobalRegistry().GetModelInfo(modelName)
+	if info == nil || len(info.SupportedEndpoints) == 0 {
+		return "", false
+	}
+	if endpointListContains(info.SupportedEndpoints, requestedEndpoint) {
+		return "", false
+	}
+	if requestedEndpoint == openAIChatEndpoint && endpointListContains(info.SupportedEndpoints, openAIResponsesEndpoint) {
+		return openAIResponsesEndpoint, true
+	}
+	if requestedEndpoint == openAIResponsesEndpoint && endpointListContains(info.SupportedEndpoints, openAIChatEndpoint) {
+		return openAIChatEndpoint, true
+	}
+	return "", false
+}
+
+func endpointListContains(items []string, value string) bool {
+	for _, item := range items {
+		if item == value {
+			return true
+		}
+	}
+	return false
+}

sdk/api/handlers/openai/openai_handlers.go

@@ -17,6 +17,7 @@ import (
 	. "github.com/router-for-me/CLIProxyAPI/v6/internal/constant"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
+	codexconverter "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/codex/openai/chat-completions"
 	responsesconverter "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/openai/openai/responses"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers"
 	"github.com/tidwall/gjson"
@@ -112,6 +113,23 @@ func (h *OpenAIAPIHandler) ChatCompletions(c *gin.Context) {
 	streamResult := gjson.GetBytes(rawJSON, "stream")
 	stream := streamResult.Type == gjson.True
 
+	modelName := gjson.GetBytes(rawJSON, "model").String()
+	if overrideEndpoint, ok := resolveEndpointOverride(modelName, openAIChatEndpoint); ok && overrideEndpoint == openAIResponsesEndpoint {
+		originalChat := rawJSON
+		if shouldTreatAsResponsesFormat(rawJSON) {
+			// Already responses-style payload; no conversion needed.
+		} else {
+			rawJSON = codexconverter.ConvertOpenAIRequestToCodex(modelName, rawJSON, stream)
+		}
+		stream = gjson.GetBytes(rawJSON, "stream").Bool()
+		if stream {
+			h.handleStreamingResponseViaResponses(c, rawJSON, originalChat)
+		} else {
+			h.handleNonStreamingResponseViaResponses(c, rawJSON, originalChat)
+		}
+		return
+	}
+
 	// Some clients send OpenAI Responses-format payloads to /v1/chat/completions.
 	// Convert them to Chat Completions so downstream translators preserve tool metadata.
 	if shouldTreatAsResponsesFormat(rawJSON) {
@@ -245,6 +263,76 @@ func convertCompletionsRequestToChatCompletions(rawJSON []byte) []byte {
 	return []byte(out)
 }
 
+func convertResponsesObjectToChatCompletion(ctx context.Context, modelName string, originalChatJSON, responsesRequestJSON, responsesPayload []byte) []byte {
+	if len(responsesPayload) == 0 {
+		return nil
+	}
+	wrapped := wrapResponsesPayloadAsCompleted(responsesPayload)
+	if len(wrapped) == 0 {
+		return nil
+	}
+	var param any
+	converted := codexconverter.ConvertCodexResponseToOpenAINonStream(ctx, modelName, originalChatJSON, responsesRequestJSON, wrapped, &param)
+	if converted == "" {
+		return nil
+	}
+	return []byte(converted)
+}
+
+func wrapResponsesPayloadAsCompleted(payload []byte) []byte {
+	if gjson.GetBytes(payload, "type").Exists() {
+		return payload
+	}
+	if gjson.GetBytes(payload, "object").String() != "response" {
+		return payload
+	}
+	wrapped := `{"type":"response.completed","response":{}}`
+	wrapped, _ = sjson.SetRaw(wrapped, "response", string(payload))
+	return []byte(wrapped)
+}
+
+func writeConvertedResponsesChunk(c *gin.Context, ctx context.Context, modelName string, originalChatJSON, responsesRequestJSON, chunk []byte, param *any) {
+	outputs := codexconverter.ConvertCodexResponseToOpenAI(ctx, modelName, originalChatJSON, responsesRequestJSON, chunk, param)
+	for _, out := range outputs {
+		if out == "" {
+			continue
+		}
+		_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", out)
+	}
+}
+
+func (h *OpenAIAPIHandler) forwardResponsesAsChatStream(c *gin.Context, flusher http.Flusher, cancel func(error), data <-chan []byte, errs <-chan *interfaces.ErrorMessage, ctx context.Context, modelName string, originalChatJSON, responsesRequestJSON []byte, param *any) {
+	h.ForwardStream(c, flusher, cancel, data, errs, handlers.StreamForwardOptions{
+		WriteChunk: func(chunk []byte) {
+			outputs := codexconverter.ConvertCodexResponseToOpenAI(ctx, modelName, originalChatJSON, responsesRequestJSON, chunk, param)
+			for _, out := range outputs {
+				if out == "" {
+					continue
+				}
+				_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", out)
+			}
+		},
+		WriteTerminalError: func(errMsg *interfaces.ErrorMessage) {
+			if errMsg == nil {
+				return
+			}
+			status := http.StatusInternalServerError
+			if errMsg.StatusCode > 0 {
+				status = errMsg.StatusCode
+			}
+			errText := http.StatusText(status)
+			if errMsg.Error != nil && errMsg.Error.Error() != "" {
+				errText = errMsg.Error.Error()
+			}
+			body := handlers.BuildErrorResponseBody(status, errText)
+			_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", string(body))
+		},
+		WriteDone: func() {
+			_, _ = fmt.Fprintf(c.Writer, "data: [DONE]\n\n")
+		},
+	})
+}
+
 // convertChatCompletionsResponseToCompletions converts chat completions API response back to completions format.
 // This ensures the completions endpoint returns data in the expected format.
 //
@@ -435,6 +523,30 @@ func (h *OpenAIAPIHandler) handleNonStreamingResponse(c *gin.Context, rawJSON []
 	cliCancel()
 }
 
+func (h *OpenAIAPIHandler) handleNonStreamingResponseViaResponses(c *gin.Context, rawJSON []byte, originalChatJSON []byte) {
+	c.Header("Content-Type", "application/json")
+
+	modelName := gjson.GetBytes(rawJSON, "model").String()
+	cliCtx, cliCancel := h.GetContextWithCancel(h, c, context.Background())
+	resp, errMsg := h.ExecuteWithAuthManager(cliCtx, OpenaiResponse, modelName, rawJSON, h.GetAlt(c))
+	if errMsg != nil {
+		h.WriteErrorResponse(c, errMsg)
+		cliCancel(errMsg.Error)
+		return
+	}
+	converted := convertResponsesObjectToChatCompletion(cliCtx, modelName, originalChatJSON, rawJSON, resp)
+	if converted == nil {
+		h.WriteErrorResponse(c, &interfaces.ErrorMessage{
+			StatusCode: http.StatusInternalServerError,
+			Error:      fmt.Errorf("failed to convert response to chat completion format"),
+		})
+		cliCancel(fmt.Errorf("response conversion failed"))
+		return
+	}
+	_, _ = c.Writer.Write(converted)
+	cliCancel()
+}
+
 // handleStreamingResponse handles streaming responses for Gemini models.
 // It establishes a streaming connection with the backend service and forwards
 // the response chunks to the client in real-time using Server-Sent Events.
@@ -509,6 +621,67 @@ func (h *OpenAIAPIHandler) handleStreamingResponse(c *gin.Context, rawJSON []byt
 	}
 }
 
+func (h *OpenAIAPIHandler) handleStreamingResponseViaResponses(c *gin.Context, rawJSON []byte, originalChatJSON []byte) {
+	flusher, ok := c.Writer.(http.Flusher)
+	if !ok {
+		c.JSON(http.StatusInternalServerError, handlers.ErrorResponse{
+			Error: handlers.ErrorDetail{
+				Message: "Streaming not supported",
+				Type:    "server_error",
+			},
+		})
+		return
+	}
+
+	modelName := gjson.GetBytes(rawJSON, "model").String()
+	cliCtx, cliCancel := h.GetContextWithCancel(h, c, context.Background())
+	dataChan, errChan := h.ExecuteStreamWithAuthManager(cliCtx, OpenaiResponse, modelName, rawJSON, h.GetAlt(c))
+	var param any
+
+	setSSEHeaders := func() {
+		c.Header("Content-Type", "text/event-stream")
+		c.Header("Cache-Control", "no-cache")
+		c.Header("Connection", "keep-alive")
+		c.Header("Access-Control-Allow-Origin", "*")
+	}
+
+	// Peek for first usable chunk
+	for {
+		select {
+		case <-c.Request.Context().Done():
+			cliCancel(c.Request.Context().Err())
+			return
+		case errMsg, ok := <-errChan:
+			if !ok {
+				errChan = nil
+				continue
+			}
+			h.WriteErrorResponse(c, errMsg)
+			if errMsg != nil {
+				cliCancel(errMsg.Error)
+			} else {
+				cliCancel(nil)
+			}
+			return
+		case chunk, ok := <-dataChan:
+			if !ok {
+				setSSEHeaders()
+				_, _ = fmt.Fprintf(c.Writer, "data: [DONE]\n\n")
+				flusher.Flush()
+				cliCancel(nil)
+				return
+			}
+
+			setSSEHeaders()
+			writeConvertedResponsesChunk(c, cliCtx, modelName, originalChatJSON, rawJSON, chunk, &param)
+			flusher.Flush()
+
+			h.forwardResponsesAsChatStream(c, flusher, func(err error) { cliCancel(err) }, dataChan, errChan, cliCtx, modelName, originalChatJSON, rawJSON, &param)
+			return
+		}
+	}
+}
+
 // handleCompletionsNonStreamingResponse handles non-streaming completions responses.
 // It converts completions request to chat completions format, sends to backend,
 // then converts the response back to completions format before sending to client.

sdk/api/handlers/openai/openai_responses_handlers.go

@@ -16,6 +16,7 @@ import (
 	. "github.com/router-for-me/CLIProxyAPI/v6/internal/constant"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
+	responsesconverter "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/openai/openai/responses"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers"
 	"github.com/tidwall/gjson"
 )
@@ -83,7 +84,21 @@ func (h *OpenAIResponsesAPIHandler) Responses(c *gin.Context) {
 
 	// Check if the client requested a streaming response.
 	streamResult := gjson.GetBytes(rawJSON, "stream")
-	if streamResult.Type == gjson.True {
+	stream := streamResult.Type == gjson.True
+
+	modelName := gjson.GetBytes(rawJSON, "model").String()
+	if overrideEndpoint, ok := resolveEndpointOverride(modelName, openAIResponsesEndpoint); ok && overrideEndpoint == openAIChatEndpoint {
+		chatJSON := responsesconverter.ConvertOpenAIResponsesRequestToOpenAIChatCompletions(modelName, rawJSON, stream)
+		stream = gjson.GetBytes(chatJSON, "stream").Bool()
+		if stream {
+			h.handleStreamingResponseViaChat(c, rawJSON, chatJSON)
+		} else {
+			h.handleNonStreamingResponseViaChat(c, rawJSON, chatJSON)
+		}
+		return
+	}
+
+	if stream {
 		h.handleStreamingResponse(c, rawJSON)
 	} else {
 		h.handleNonStreamingResponse(c, rawJSON)
@@ -116,6 +131,31 @@ func (h *OpenAIResponsesAPIHandler) handleNonStreamingResponse(c *gin.Context, r
 	cliCancel()
 }
 
+func (h *OpenAIResponsesAPIHandler) handleNonStreamingResponseViaChat(c *gin.Context, originalResponsesJSON, chatJSON []byte) {
+	c.Header("Content-Type", "application/json")
+
+	modelName := gjson.GetBytes(chatJSON, "model").String()
+	cliCtx, cliCancel := h.GetContextWithCancel(h, c, context.Background())
+	resp, errMsg := h.ExecuteWithAuthManager(cliCtx, OpenAI, modelName, chatJSON, "")
+	if errMsg != nil {
+		h.WriteErrorResponse(c, errMsg)
+		cliCancel(errMsg.Error)
+		return
+	}
+	var param any
+	converted := responsesconverter.ConvertOpenAIChatCompletionsResponseToOpenAIResponsesNonStream(cliCtx, modelName, originalResponsesJSON, originalResponsesJSON, resp, &param)
+	if converted == "" {
+		h.WriteErrorResponse(c, &interfaces.ErrorMessage{
+			StatusCode: http.StatusInternalServerError,
+			Error:      fmt.Errorf("failed to convert chat completion response to responses format"),
+		})
+		cliCancel(fmt.Errorf("response conversion failed"))
+		return
+	}
+	_, _ = c.Writer.Write([]byte(converted))
+	cliCancel()
+}
+
 // handleStreamingResponse handles streaming responses for Gemini models.
 // It establishes a streaming connection with the backend service and forwards
 // the response chunks to the client in real-time using Server-Sent Events.
@@ -196,6 +236,116 @@ func (h *OpenAIResponsesAPIHandler) handleStreamingResponse(c *gin.Context, rawJ
 	}
 }
 
+func (h *OpenAIResponsesAPIHandler) handleStreamingResponseViaChat(c *gin.Context, originalResponsesJSON, chatJSON []byte) {
+	flusher, ok := c.Writer.(http.Flusher)
+	if !ok {
+		c.JSON(http.StatusInternalServerError, handlers.ErrorResponse{
+			Error: handlers.ErrorDetail{
+				Message: "Streaming not supported",
+				Type:    "server_error",
+			},
+		})
+		return
+	}
+
+	modelName := gjson.GetBytes(chatJSON, "model").String()
+	cliCtx, cliCancel := h.GetContextWithCancel(h, c, context.Background())
+	dataChan, errChan := h.ExecuteStreamWithAuthManager(cliCtx, OpenAI, modelName, chatJSON, "")
+	var param any
+
+	setSSEHeaders := func() {
+		c.Header("Content-Type", "text/event-stream")
+		c.Header("Cache-Control", "no-cache")
+		c.Header("Connection", "keep-alive")
+		c.Header("Access-Control-Allow-Origin", "*")
+	}
+
+	for {
+		select {
+		case <-c.Request.Context().Done():
+			cliCancel(c.Request.Context().Err())
+			return
+		case errMsg, ok := <-errChan:
+			if !ok {
+				errChan = nil
+				continue
+			}
+			h.WriteErrorResponse(c, errMsg)
+			if errMsg != nil {
+				cliCancel(errMsg.Error)
+			} else {
+				cliCancel(nil)
+			}
+			return
+		case chunk, ok := <-dataChan:
+			if !ok {
+				setSSEHeaders()
+				_, _ = c.Writer.Write([]byte("\n"))
+				flusher.Flush()
+				cliCancel(nil)
+				return
+			}
+
+			setSSEHeaders()
+			writeChatAsResponsesChunk(c, cliCtx, modelName, originalResponsesJSON, chunk, &param)
+			flusher.Flush()
+
+			h.forwardChatAsResponsesStream(c, flusher, func(err error) { cliCancel(err) }, dataChan, errChan, cliCtx, modelName, originalResponsesJSON, &param)
+			return
+		}
+	}
+}
+
+func writeChatAsResponsesChunk(c *gin.Context, ctx context.Context, modelName string, originalResponsesJSON, chunk []byte, param *any) {
+	outputs := responsesconverter.ConvertOpenAIChatCompletionsResponseToOpenAIResponses(ctx, modelName, originalResponsesJSON, originalResponsesJSON, chunk, param)
+	for _, out := range outputs {
+		if out == "" {
+			continue
+		}
+		if bytes.HasPrefix([]byte(out), []byte("event:")) {
+			_, _ = c.Writer.Write([]byte("\n"))
+		}
+		_, _ = c.Writer.Write([]byte(out))
+		_, _ = c.Writer.Write([]byte("\n"))
+	}
+}
+
+func (h *OpenAIResponsesAPIHandler) forwardChatAsResponsesStream(c *gin.Context, flusher http.Flusher, cancel func(error), data <-chan []byte, errs <-chan *interfaces.ErrorMessage, ctx context.Context, modelName string, originalResponsesJSON []byte, param *any) {
+	h.ForwardStream(c, flusher, cancel, data, errs, handlers.StreamForwardOptions{
+		WriteChunk: func(chunk []byte) {
+			outputs := responsesconverter.ConvertOpenAIChatCompletionsResponseToOpenAIResponses(ctx, modelName, originalResponsesJSON, originalResponsesJSON, chunk, param)
+			for _, out := range outputs {
+				if out == "" {
+					continue
+				}
+				if bytes.HasPrefix([]byte(out), []byte("event:")) {
+					_, _ = c.Writer.Write([]byte("\n"))
+				}
+				_, _ = c.Writer.Write([]byte(out))
+				_, _ = c.Writer.Write([]byte("\n"))
+			}
+		},
+		WriteTerminalError: func(errMsg *interfaces.ErrorMessage) {
+			if errMsg == nil {
+				return
+			}
+			status := http.StatusInternalServerError
+			if errMsg.StatusCode > 0 {
+				status = errMsg.StatusCode
+			}
+			errText := http.StatusText(status)
+			if errMsg.Error != nil && errMsg.Error.Error() != "" {
+				errText = errMsg.Error.Error()
+			}
+			body := handlers.BuildErrorResponseBody(status, errText)
+			_, _ = fmt.Fprintf(c.Writer, "\nevent: error\ndata: %s\n\n", string(body))
+		},
+		WriteDone: func() {
+			_, _ = c.Writer.Write([]byte("\n"))
+		},
+	})
+}
+
 func (h *OpenAIResponsesAPIHandler) forwardResponsesStream(c *gin.Context, flusher http.Flusher, cancel func(error), data <-chan []byte, errs <-chan *interfaces.ErrorMessage) {
 	h.ForwardStream(c, flusher, cancel, data, errs, handlers.StreamForwardOptions{
 		WriteChunk: func(chunk []byte) {