feat(routing): route Codex thread descriptions independently

internal/gateway/codex_backend.go

@@ -91,6 +91,10 @@ func (s *Server) codexBackend(w http.ResponseWriter, r *http.Request) {
 				s.codexTitle(w, r, body, to)
 				return
 			}
+			if to := codexDescriptionsTo(r.Header, body); to != "" {
+				s.codexDescription(w, r, body, to)
+				return
+			}
 		}
 		// The namespace owns the route even if a model is not in the catalog.
 		// Unknown providers/groups must fail locally, never fall through to OpenAI.

internal/gateway/codex_titles.go

@@ -40,6 +40,17 @@ func codexTitlesTo(h http.Header, body []byte, ours bool) string {
 	return ""
 }
 
+// codexDescriptionsTo is where a request Codex makes for a thread's
+// description goes. "" leaves the request as Codex sent it; a model's id
+// writes it. A description is not a title: Codex asks for {"description"}
+// alone, which the title wrapper cannot answer.
+func codexDescriptionsTo(h http.Header, body []byte) string {
+	if !isDescriptionKind(requestCallKind(h, requestSessionMetadata(h, body))) {
+		return ""
+	}
+	return settings.Load().CodexDescriptions
+}
+
 // titleCheckKey holds, in a request's context, what serve asks of the
 // reply it relayed before it records the call: the reason it fails its
 // caller although the vendor answered, or "".
@@ -112,6 +123,107 @@ func (s *Server) codexTitle(w http.ResponseWriter, r *http.Request, body []byte,
 	writeTitleReply(w, id, out, res.Usage)
 }
 
+// codexDescription answers a thread_description request with the model
+// CodexDescriptions names. The model's text comes back as the
+// {"description": ...} its schema asks for; a reply without one fails as a
+// description, not as a title.
+func (s *Server) codexDescription(w http.ResponseWriter, r *http.Request, body []byte, to string) {
+	shape := descriptionShapeOf(body)
+	body, _ = codexInput(body, true)
+	rec := &recorder{header: http.Header{}, status: 200}
+	check := func(reply string) string {
+		if res, err := compactReply([]byte(reply)); err == nil && descriptionJSON(messageText(res), shape) == "" {
+			return noDescription(messageText(res))
+		}
+		return ""
+	}
+	ctx := context.WithValue(r.Context(), titleCheckKey{}, check)
+	ctx = magpieChose(ctx)
+	s.serve(rec, r.WithContext(ctx), provider.Responses, withModel(body, to))
+	if rec.status >= 400 {
+		for k, vs := range rec.header {
+			w.Header()[k] = vs
+		}
+		w.WriteHeader(rec.status)
+		w.Write(rec.body.Bytes())
+		return
+	}
+	res, err := compactReply(rec.body.Bytes())
+	if err != nil {
+		writeError(w, provider.Responses, 502, "description: "+err.Error())
+		return
+	}
+	id := res.ID
+	if id == "" {
+		id = fmt.Sprintf("resp_magpie_%d", time.Now().UnixNano())
+	}
+	var out []any
+	if d := descriptionJSON(messageText(res), shape); d != "" {
+		out = append(out, map[string]any{"type": "message", "id": "msg_" + strings.TrimPrefix(id, "resp_"), "role": "assistant", "status": "completed",
+			"content": []any{map[string]any{"type": "output_text", "text": d, "annotations": []any{}}}})
+	}
+	writeTitleReply(w, id, out, res.Usage)
+}
+
+func noDescription(said string) string {
+	said = strings.Join(strings.Fields(said), " ")
+	if said == "" {
+		return "description: the model answered with no text, so Codex got no description"
+	}
+	if r := []rune(said); len(r) > 80 {
+		said = string(r[:80]) + "…"
+	}
+	return "description: no description in the model's answer, so Codex got none: " + said
+}
+
+// descriptionShape is the {"description"} object a description request asks
+// for. Its max length is all magpie needs: the reply contains that one field.
+type descriptionShape struct {
+	MaxLength int
+}
+
+func descriptionShapeOf(body []byte) descriptionShape {
+	shape := titleShapeOf(body)
+	return descriptionShape{MaxLength: shape.Properties["description"].MaxLength}
+}
+
+// descriptionJSON is a model's answer as {"description": "..."}, cut to the
+// schema's length. "" when the answer gave none.
+func descriptionJSON(said string, shape descriptionShape) string {
+	t := strings.TrimSpace(said)
+	if rest, ok := strings.CutPrefix(t, "<think>"); ok {
+		if _, after, ok := strings.Cut(rest, "</think>"); ok {
+			t = strings.TrimSpace(after)
+		}
+	}
+	if strings.HasPrefix(t, "```") {
+		t = strings.TrimPrefix(t, "```")
+		if i := strings.IndexByte(t, '\n'); i >= 0 && !strings.Contains(t[:i], "{") {
+			t = t[i+1:]
+		}
+		t = strings.TrimSpace(strings.TrimSuffix(strings.TrimSpace(t), "```"))
+	}
+	if strings.HasPrefix(t, "{") {
+		fields := map[string]any{}
+		if json.NewDecoder(bytes.NewReader([]byte(t))).Decode(&fields) == nil {
+			if v, ok := fields["description"].(string); ok {
+				t = v
+			}
+		}
+	}
+	t = strings.TrimSpace(strings.Trim(strings.TrimSpace(t), "\"`'"))
+	if t == "" || strings.HasPrefix(t, "{") {
+		return ""
+	}
+	if n := shape.MaxLength; n > 0 {
+		if r := []rune(t); len(r) > n {
+			t = strings.TrimSpace(string(r[:n]))
+		}
+	}
+	b, _ := json.Marshal(map[string]string{"description": t})
+	return string(b)
+}
+
 // messageText is the text of a reply's messages, its reasoning left out.
 func messageText(res compactResult) string {
 	var said strings.Builder

internal/gateway/codex_titles_test.go

@@ -286,3 +286,81 @@ func TestTitleJSONFillsTheSchema(t *testing.T) {
 		t.Errorf("no schema: %s", got)
 	}
 }
+
+func codexDescriptionRequest(t *testing.T, s *Server) *httptest.ResponseRecorder {
+	t.Helper()
+	body := `{"model":"gpt-6-luna","stream":true,"input":[{"type":"message","role":"user","content":[{"type":"input_text","text":"Describe the thread"}]}],` +
+		`"text":{"format":{"type":"json_schema","strict":true,"schema":{"type":"object","properties":{"description":{"type":"string","maxLength":24}},"required":["description"],"additionalProperties":false}}}}`
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest("POST", CodexPath+"/responses", strings.NewReader(body))
+	req.Header.Set("Authorization", "Bearer chatgpt-token")
+	req.Header.Set("session_id", "description-thread")
+	req.Header.Set("x-codex-turn-metadata", `{"thread_source":"thread_description"}`)
+	s.Handler().ServeHTTP(rec, req)
+	return rec
+}
+
+func TestCodexDescriptionsSetting(t *testing.T) {
+	f := &fake{t: t, reply: sse(
+		`data: {"id":"c1","choices":[{"index":0,"delta":{"content":"Reviewed the routing change and verified it"}}]}`,
+		`data: {"id":"c1","choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":30,"completion_tokens":8}}`,
+		`data: [DONE]`)}
+	setup(t, provider.Chat, f)
+	chatgptCalls := 0
+	chatgpt(t, func(w http.ResponseWriter, r *http.Request) {
+		io.ReadAll(r.Body)
+		chatgptCalls++
+		w.Header().Set("Content-Type", "text/event-stream")
+		io.WriteString(w, sse(`data: {"type":"response.completed","response":{"id":"r1","output":[{"type":"message","role":"assistant","content":[{"type":"output_text","text":"{\"description\":\"From ChatGPT\"}"}]}],"usage":{"input_tokens":9,"output_tokens":2}}}`))
+	})
+	save := func(v string) {
+		t.Helper()
+		st := settings.Load()
+		st.CodexDescriptions = v
+		if err := settings.Save(st); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	s := New()
+	rec := codexDescriptionRequest(t, s)
+	if text, _ := outputText(t, rec.Body.String()); chatgptCalls != 1 || f.calls != 0 || text != `{"description":"From ChatGPT"}` {
+		t.Fatalf("default: chatgpt %d, magpie model %d, %q", chatgptCalls, f.calls, text)
+	}
+
+	save("fake/m1")
+	rec = codexDescriptionRequest(t, s)
+	if text, _ := outputText(t, rec.Body.String()); rec.Code != 200 || text != `{"description":"Reviewed the routing cha"}` || f.calls != 1 || chatgptCalls != 1 {
+		t.Fatalf("routed: %d %q, magpie model %d, chatgpt %d", rec.Code, rec.Body.String(), f.calls, chatgptCalls)
+	}
+	var sent struct {
+		Model string `json:"model"`
+	}
+	json.Unmarshal(f.got, &sent)
+	if sent.Model != "m1" {
+		t.Errorf("the magpie model was asked for %q", sent.Model)
+	}
+	var kinds []string
+	for _, u := range usage.Load(time.Time{}) {
+		kinds = append(kinds, u.Provider+":"+u.Kind)
+	}
+	want := "openai:thread_description fake:thread_description"
+	if got := strings.Join(kinds, " "); got != want {
+		t.Errorf("ledger %s\nwant   %s", got, want)
+	}
+}
+
+func TestDescriptionJSON(t *testing.T) {
+	body := `{"text":{"format":{"schema":{"properties":{"description":{"type":"string","maxLength":11}}}}}}`
+	shape := descriptionShapeOf([]byte(body))
+	for in, want := range map[string]string{
+		"A short note":                               `{"description":"A short not"}`,
+		`{"description":"From JSON"}`:                `{"description":"From JSON"}`,
+		"```json\n{\"description\":\"Fenced\"}\n```": `{"description":"Fenced"}`,
+		"": "",
+	} {
+		if got := descriptionJSON(in, shape); got != want {
+			t.Errorf("descriptionJSON(%q) = %s, want %s", in, got, want)
+		}
+	}
+}

internal/gateway/gateway.go

@@ -1057,6 +1057,10 @@ func (s *Server) handle(from provider.Protocol) http.HandlerFunc {
 				s.codexTitle(w, r, body, to)
 				return
 			}
+			if to := codexDescriptionsTo(r.Header, body); to != "" {
+				s.codexDescription(w, r, body, to)
+				return
+			}
 		}
 		s.serveAgent(w, r, from, body)
 	}

internal/gateway/session_parent.go

@@ -11,6 +11,10 @@ func isTitleKind(kind string) bool {
 	return kind == "thread_title" || kind == "thread_title_reconsideration" || kind == "title_generation"
 }
 
+func isDescriptionKind(kind string) bool {
+	return kind == "thread_description"
+}
+
 // Codex projects turn metadata into headers, but its canonical transport is
 // client_metadata in the Responses body. Read only identity fields; never keep
 // prompts or the rest of the metadata in the trace.

internal/gui/api.go

@@ -1010,7 +1010,8 @@ func Handler(w Windows, gw *gateway.Server) http.Handler {
 		in.FullContext = cur.FullContext // set on its own (full-context below)
 		in.CompactAt = cur.CompactAt     // and so is the threshold
 
-		in.CodexTitles = cur.CodexTitles // set on its own (codex-titles below)
+		in.CodexTitles = cur.CodexTitles             // set on its own (codex-titles below)
+		in.CodexDescriptions = cur.CodexDescriptions // set on its own (codex-descriptions below)
 		// and so is the model Codex's auto-review runs on (codex-auto-review)
 		in.CodexAutoReview = cur.CodexAutoReview
 		in.ChinaMirror = cur.ChinaMirror // the Plugins page's, set on its own
@@ -1184,6 +1185,29 @@ func Handler(w Windows, gw *gateway.Server) http.Handler {
 		}
 		writeJSON(rw, settingsState())
 	})
+	// where Codex's request for a thread's description goes: "" as Codex
+	// sends it, or a model's id. It is separate from the title setting.
+	mux.HandleFunc("POST /api/settings/codex-descriptions", func(rw http.ResponseWriter, r *http.Request) {
+		var in struct{ Model string }
+		if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
+			fail(rw, err)
+			return
+		}
+		v := strings.TrimSpace(in.Model)
+		if v != "" {
+			if _, _, ok := provider.Resolve(v); !ok {
+				fail(rw, fmt.Errorf("no model %s to write Codex's descriptions", v))
+				return
+			}
+		}
+		s := settings.Load()
+		s.CodexDescriptions = v
+		if err := settings.Save(s); err != nil {
+			fail(rw, err)
+			return
+		}
+		writeJSON(rw, settingsState())
+	})
 	// where Codex's requests for a thread's title go (#705): "" as Codex
 	// sends them, "off", or a model's id
 	mux.HandleFunc("POST /api/settings/codex-titles", func(rw http.ResponseWriter, r *http.Request) {

internal/gui/assets/app.js

@@ -17738,7 +17738,7 @@ function renderSettings() {
   // gateway mode leaves out what is written into this computer's agents'
   // files, and the alerts its desktop would show
   for (const r of [$("#plainNamesSegs").parentElement, $("#codexAgentsV1Segs").parentElement, $("#fullContextSegs").parentElement,
-    $("#codexTitlesRow"), $("#codexAutoReviewRow"), $("#usageAlertRow"), $("#balanceAlertRow"), $("#resetReminderRow")]) r.hidden = gatewayMode;
+    $("#codexTitlesRow"), $("#codexDescriptionsRow"), $("#codexAutoReviewRow"), $("#usageAlertRow"), $("#balanceAlertRow"), $("#resetReminderRow")]) r.hidden = gatewayMode;
   // the parts' tabs, one gone whose rows are all hidden here
   setSetTab(setTab);
 }
@@ -18223,6 +18223,7 @@ function renderTrayUsage(s, keep) {
   compactRow.append(compactSegs, compactNum);
   $("#fullContextSegs").replaceChildren(compactRow);
   renderCodexTitles(s);
+  renderCodexDescriptions(s);
   renderCodexAutoReview(s);
   renderCodexMemories();
   const rate = s.fx?.rate;
@@ -18492,6 +18493,31 @@ function renderAlerts(s, keep) {
 // — as Codex sends them, to its own model through its ChatGPT sign-in; off,
 // answered by magpie with no title; or to a model of magpie's — set on its
 // own, as Codex's subagents are.
+function renderCodexDescriptions(s) {
+  const models = s.titleModels || [];
+  const named = (id) => {
+    const m = models.find((x) => x.id === id);
+    return m ? `${m.name || m.id} · ${m.providerName}` : id;
+  };
+  const v = s.codexDescriptions || "";
+  $("#codexDescriptionsSub").textContent = v ? t("Codex’s description requests go to this model, not to its ChatGPT sign-in; the Usage and Routing views still show them as descriptions")
+    : t("Codex asks its own model for each thread’s description through its ChatGPT sign-in, even while the conversation is on magpie’s models");
+  const b = el("button", "rt-cond on");
+  b.type = "button";
+  b.setAttribute("aria-label", t("Codex thread descriptions"));
+  if (v) b.append(icon(models.find((x) => x.id === v)?.icon || "generic"), el("span", "", named(v)));
+  else b.append(icon("openai"), el("span", "", t("Codex’s own (ChatGPT)")));
+  const opt = (x) => ({ value: x.id, label: x.name || x.id, note: x.providerName, icon: x.icon, group: x.provider ? x.providerName : ROUTING_GROUPS, ref: x.id });
+  b.onclick = (ev) => openPicker({ id: "", name: "", fields: [] }, { key: "codexDescriptions", label: "model", value: v, options: [
+    { value: "", label: t("Codex’s own (ChatGPT)"), note: t("as Codex sends them"), icon: "openai", reset: true },
+    ...models.map(opt)],
+  onPick: (id) => {
+    if (id === v) return;
+    writingPrefs(api("settings/codex-descriptions", { model: id })).then((ns) => { prefs = ns; renderSettings(); }).catch((e) => { status(t(e.message), "err"); renderSettings(); });
+  } }, b, ev);
+  $("#codexDescriptionsPick").replaceChildren(b);
+}
+
 function renderCodexTitles(s) {
   const models = s.titleModels || [];
   const named = (id) => {

internal/gui/assets/i18n.js

@@ -559,6 +559,9 @@ const I18N = {
     "Full window": "完整窗口",
     "Compact at {n}": "{n} 时压缩",
     "Codex thread titles": "Codex 会话标题",
+    "Codex thread descriptions": "Codex 会话描述",
+    "Codex asks its own model for each thread’s description through its ChatGPT sign-in, even while the conversation is on magpie’s models": "Codex 经 ChatGPT 登录用自带模型为每个会话生成描述，即使对话用的是 magpie 的模型",
+    "Codex’s description requests go to this model, not to its ChatGPT sign-in; the Usage and Routing views still show them as descriptions": "Codex 的描述请求改由此模型生成，不经 ChatGPT 登录；用量和路由页仍记为描述请求",
     "Codex’s own (ChatGPT)": "Codex 自带（ChatGPT）",
     "as Codex sends them": "按 Codex 原样发送",
     "Codex auto-review model": "Codex 自动审批模型",

internal/gui/assets/index.html

@@ -294,6 +294,10 @@ <h1 class="sr-only" id="pageTitle" data-t>Agents</h1>
         <div class="who"><div class="name" data-t>Codex thread titles</div><div class="sub" id="codexTitlesSub"></div></div>
         <div class="val" id="codexTitlesPick"></div>
       </div>
+      <div class="row pref" id="codexDescriptionsRow">
+        <div class="who"><div class="name" data-t>Codex thread descriptions</div><div class="sub" id="codexDescriptionsSub"></div></div>
+        <div class="val" id="codexDescriptionsPick"></div>
+      </div>
       <div class="row pref" id="codexAutoReviewRow">
         <div class="who"><div class="name" data-t>Codex auto-review model</div><div class="sub" id="codexAutoReviewSub"></div></div>
         <div class="val" id="codexAutoReviewPick"></div>

internal/gui/assets/purposes.js

@@ -52,6 +52,10 @@ const REQUEST_KINDS = {
     "purpose": "kind:review",
     "name": "Review"
   },
+  "thread_description": {
+    "purpose": "kind:thread_description",
+    "name": "Description"
+  },
   "thread_spawn": {
     "purpose": "kind:collab_spawn",
     "name": "Subagent"