diff --git a/.downstream/gpt6-routing-and-prompts.md b/.downstream/gpt6-routing-and-prompts.md
index a9d5374c3b2c..40f5ba5bffd6 100644
--- a/.downstream/gpt6-routing-and-prompts.md
+++ b/.downstream/gpt6-routing-and-prompts.md
@@ -29,6 +29,7 @@ API Key 使用完整 Responses。OAuth 目录保留实际 Lite 与上下文字
 - 已登记且有请求需求的账号在到期前 20 秒续获。每周期最多一次采集与一次复验，连续两个失败周期后持久停止；闲置账号不持续探测。`fail_closed` 保留。
 - 旧 292 不转换为 Cookie 验证成功，旧停止状态保留。原先默认的 Astra/5.6-Sol 名单只在旧配置版本迁移时追加 6-Sol/6-Luna；自定义名单保留，之后显式修改不自动补回。
 - 原生 turn-state 在同一轮固定首次值，下一轮或换账号清除。
+- ChatGPT 边缘自 2026-09-23 起不再为 `/backend-api/codex/responses` 的流式响应发送 `Content-Type`。宿主对声明接受 SSE 的 200 响应补回 `text/event-stream`，资格读取对无类型响应按 SSE 帧识别；缺少这一处理时采集、复验和业务观测都只能得到 `routing_incomplete`。
 
 账号详情右栏的“Codex 出站指纹”读取配置和已经记录的出站事实，刷新不会发模型请求。页面展示 profile 来源、UA、版本、身份摘要及一致性、传输、Cookie 名称和模型验证结果。新建账号采用官方 Windows CLI 0.156.0 的应用层参照；已有配置保留，可显式选择新版参照，设备种子和手动 UA 覆盖不被重置。
 
diff --git a/backend/internal/repository/codex_connection_lease.go b/backend/internal/repository/codex_connection_lease.go
index 03b2c048c25d..01a61d6ddcad 100644
--- a/backend/internal/repository/codex_connection_lease.go
+++ b/backend/internal/repository/codex_connection_lease.go
@@ -131,6 +131,7 @@ func (s *httpUpstreamService) DoWithCodexConnectionLease(req *http.Request, prox
 		return nil, "", service.ErrCodexConnectionLeaseTransport
 	}
 	decompressResponseBody(response)
+	restoreCodexEventStreamContentType(response)
 	return response, leaseID, nil
 }
 
diff --git a/backend/internal/repository/decompress_response_test.go b/backend/internal/repository/decompress_response_test.go
index 8de64ef0f097..0b6c1c2f86c1 100644
--- a/backend/internal/repository/decompress_response_test.go
+++ b/backend/internal/repository/decompress_response_test.go
@@ -34,6 +34,22 @@ func TestDecompressResponseBodyZstdUsage(t *testing.T) {
 	require.NoError(t, resp.Body.Close())
 }
 
+func TestRestoreCodexEventStreamContentType(t *testing.T) {
+	response := func(path string) *http.Response {
+		req, err := http.NewRequest(http.MethodPost, "https://chatgpt.com"+path, nil)
+		require.NoError(t, err)
+		req.Header.Set("Accept", "text/event-stream")
+		return &http.Response{StatusCode: http.StatusOK, Header: http.Header{}, Request: req}
+	}
+	stream := response("/backend-api/codex/responses")
+	restoreCodexEventStreamContentType(stream)
+	require.Equal(t, "text/event-stream", stream.Header.Get("Content-Type"))
+
+	compact := response("/backend-api/codex/responses/compact")
+	restoreCodexEventStreamContentType(compact)
+	require.Empty(t, compact.Header.Get("Content-Type"))
+}
+
 func TestDecompressResponseBodyExistingEncodings(t *testing.T) {
 	payload := []byte(`{"ok":true}`)
 	tests := []struct {
diff --git a/backend/internal/repository/http_upstream.go b/backend/internal/repository/http_upstream.go
index e9f4e92facce..8ee93ca6a743 100644
--- a/backend/internal/repository/http_upstream.go
+++ b/backend/internal/repository/http_upstream.go
@@ -231,6 +231,7 @@ func (s *httpUpstreamService) Do(req *http.Request, proxyURL string, accountID i
 
 	// 如果上游返回了压缩内容，解压后再交给业务层
 	decompressResponseBody(resp)
+	restoreCodexEventStreamContentType(resp)
 
 	// 包装响应体，在关闭时自动减少计数并更新时间戳
 	// 这确保了流式响应（如 SSE）在完全读取前不会被淘汰
@@ -292,6 +293,7 @@ func (s *httpUpstreamService) DoWithTLS(req *http.Request, proxyURL string, acco
 	}
 
 	decompressResponseBody(resp)
+	restoreCodexEventStreamContentType(resp)
 
 	resp.Body = wrapTrackedBody(resp.Body, func() {
 		atomic.AddInt64(&entry.inFlight, -1)
@@ -1499,6 +1501,21 @@ func wrapTrackedBody(body io.ReadCloser, onClose func()) io.ReadCloser {
 	return &trackedBody{ReadCloser: body, onClose: onClose}
 }
 
+// restoreCodexEventStreamContentType 为缺少 Content-Type 的 ChatGPT Codex /responses 流补回
+// text/event-stream。ChatGPT 边缘自 2026-09-23 起不再为这类 SSE 响应发送该头，而路由观测、
+// 工具名映射和图片流等消费方都按它识别流；请求声明接受 SSE 且上游 200 时响应体就是 SSE。
+func restoreCodexEventStreamContentType(resp *http.Response) {
+	if resp == nil || resp.StatusCode != http.StatusOK || resp.Header == nil || resp.Header.Get("Content-Type") != "" {
+		return
+	}
+	req := resp.Request
+	if req == nil || req.URL == nil || req.Method != http.MethodPost || !strings.EqualFold(req.URL.Hostname(), "chatgpt.com") ||
+		req.URL.Path != "/backend-api/codex/responses" || !strings.Contains(strings.ToLower(req.Header.Get("Accept")), "text/event-stream") {
+		return
+	}
+	resp.Header.Set("Content-Type", "text/event-stream")
+}
+
 // decompressResponseBody 根据 Content-Encoding 解压响应体。
 // 当请求显式设置了 accept-encoding 时，Go 的 Transport 不会自动解压，需要手动处理。
 // 解压成功后会删除 Content-Encoding 和 Content-Length header（长度已不准确）。
diff --git a/backend/internal/service/codex_routing_completion.go b/backend/internal/service/codex_routing_completion.go
index 74d618213e36..ef02949ee346 100644
--- a/backend/internal/service/codex_routing_completion.go
+++ b/backend/internal/service/codex_routing_completion.go
@@ -93,7 +93,9 @@ func readCodexRoutingCompletion(body io.Reader, contentType, requested string, o
 		return errCodexRoutingUnavailable
 	}
 	var completed codexRoutingCompletion
-	if strings.Contains(strings.ToLower(contentType), "text/event-stream") {
+	// The ChatGPT edge omits Content-Type on streamed replies (2026-09-23);
+	// an untyped body is still recognised by its SSE framing.
+	if strings.Contains(strings.ToLower(contentType), "text/event-stream") || (strings.TrimSpace(contentType) == "" && bodyHasSSEFraming(data)) {
 		completed.feed(data)
 	} else {
 		completed.json(data)
diff --git a/backend/internal/service/codex_routing_host.go b/backend/internal/service/codex_routing_host.go
index 9d9e768363ee..abfc01f4ed40 100644
--- a/backend/internal/service/codex_routing_host.go
+++ b/backend/internal/service/codex_routing_host.go
@@ -320,7 +320,16 @@ func (s *OpenAIGatewayService) buildCodexRoutingProbe(ctx context.Context, accou
 	session, turn := uuid.Must(uuid.NewV7()).String(), uuid.Must(uuid.NewV7()).String()
 	metadata := map[string]any{"session_id": session, "thread_id": session, "turn_id": turn, "x-codex-window-id": session + ":0"}
 	body := map[string]any{"model": model, "store": false, "stream": true, "instructions": "Reply with exactly: pong", "input": []any{map[string]any{"role": "user", "content": []any{map[string]any{"type": "input_text", "text": "ping"}}}}, "client_metadata": metadata, "prompt_cache_key": session}
+	identity, err := resolveCodexOutboundIdentityForAccountContext(ctx, account, codexAccountIdentityOverrideUA(account))
+	if err != nil {
+		return nil, err
+	}
 	headers := http.Header{}
+	// A probe has no inbound client, so it speaks as the account's outbound
+	// identity: the same triple the routing scope profile hashes.
+	headers.Set("originator", identity.originator)
+	headers.Set("user-agent", identity.userAgent)
+	headers.Set("version", identity.version)
 	headers.Set("session-id", session)
 	headers.Set("thread-id", session)
 	headers.Set("x-client-request-id", session)
diff --git a/backend/internal/service/codex_routing_test.go b/backend/internal/service/codex_routing_test.go
index c19e1930f34b..6e7646f75ee5 100644
--- a/backend/internal/service/codex_routing_test.go
+++ b/backend/internal/service/codex_routing_test.go
@@ -202,6 +202,22 @@ func TestCodexRoutingCompletionRequiresOriginalModelAndDelimitedTerminal(t *test
 			require.Equal(t, test.ok, o.ModelMatched)
 		})
 	}
+	var untyped extensionv1.CodexRoutingObservation
+	stream := `event: response.completed
+data: {"type":"response.completed","response":{"status":"completed","model":"gpt-6-astra"}}
+
+`
+	require.NoError(t, readCodexRoutingCompletion(strings.NewReader(stream), "", "gpt-6-astra", &untyped), "ChatGPT streams arrive without Content-Type")
+}
+
+func TestCodexRoutingProbeSpeaksAsAccountIdentity(t *testing.T) {
+	account := &Account{ID: 7, Platform: PlatformOpenAI, Type: AccountTypeOAuth, Credentials: map[string]any{"chatgpt_account_id": "acct-7"}}
+	request, err := (&OpenAIGatewayService{}).buildCodexRoutingProbe(context.Background(), account, "gpt-6-astra", "token", "")
+	require.NoError(t, err)
+	identity, err := resolveCodexOutboundIdentityForAccountContext(context.Background(), account, codexAccountIdentityOverrideUA(account))
+	require.NoError(t, err)
+	require.Equal(t, identity.originator, request.Header.Get("originator"))
+	require.Equal(t, identity.userAgent, request.Header.Get("User-Agent"), "probe must not fall back to Go-http-client")
 }
 
 func TestCodexRoutingHostSeparatesCandidateQualifiedAndPrivateMaterial(t *testing.T) {