fix(coach): say so when the model answered with reasoning alone

When every provider in the chain answered a Coach round with reasoning and
no reply, even after being asked once more without reasoning, the turn ended
with "could not reach a provider, please try again in a moment". The
provider was reached, and trying again in a moment changes nothing for a
model that cannot stop reasoning.

Such a chain now ends with its own code, coach.provider.reasoning_only, and
the drawer says the model only reasoned and never wrote an answer, and
suggests another model. The choice between credential_expired, rate_limited,
reasoning_only and unavailable moved into one function beside the other turn
error rules, where it is tested on its own. An un-wrapped reasoning-only
error maps the same way. Clients that do not know the code keep showing the
generic provider message.

Refs #1276

messages/de.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "In deiner Nachricht stehen Anweisungen, die meine Vorgaben überschreiben sollen. Ich bin der HealthLog-Coach und fasse ausschließlich deine eigenen Gesundheitsdaten zusammen. Formuliere deine Frage bitte in diesem Rahmen neu.",
       "errorBudget": "Du hast das heutige Coach-Limit erreicht. Das Budget setzt sich um Mitternacht in deiner Zeitzone zurück.",
       "errorProvider": "Der Coach konnte gerade keinen Auswertungs-Anbieter erreichen. Bitte versuche es in einem Moment erneut.",
+      "errorReasoningOnly": "Das Modell hat nur nachgedacht und keine Antwort geschrieben. Versuche es noch einmal oder wähle in den KI-Einstellungen ein anderes Modell.",
       "errorDemo": "In der Demo antwortet der Coach nicht.",
       "errorNoProvider": "Der Coach liest deine erfassten Gesundheitsdaten und beantwortet Fragen dazu (keine medizinische Beratung). Dafür braucht HealthLog einen KI-Anbieter. Verbinde deinen eigenen Schlüssel oder ein lokales Modell.",
       "errorNoProviderAction": "KI-Anbieter verbinden",

messages/en.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "I noticed wording that tries to override my instructions. I am the HealthLog Coach and only summarise your own health data. Please rephrase your question in those terms.",
       "errorBudget": "You've reached today's Coach usage limit. The budget refreshes at midnight in your time zone.",
       "errorProvider": "The Coach could not reach an Insights provider just now. Please try again in a moment.",
+      "errorReasoningOnly": "The model only reasoned and never wrote an answer. Try again, or choose a different model in your AI settings.",
       "errorDemo": "The Coach doesn't answer in the demo.",
       "errorNoProvider": "The Coach reads your logged health data and answers questions about it (not medical advice). HealthLog needs an AI provider for that. Connect your own key or a local model.",
       "errorNoProviderAction": "Connect an AI provider",

messages/es.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Tu mensaje contiene instrucciones que pretenden sobrescribir mis indicaciones. Soy el coach de HealthLog y solo resumo tus propios datos de salud. Reformula tu pregunta dentro de ese marco.",
       "errorBudget": "Has alcanzado el límite diario del coach. El cupo se reinicia a medianoche en tu zona horaria.",
       "errorProvider": "El coach no ha podido contactar con un proveedor de análisis ahora mismo. Inténtalo en un momento.",
+      "errorReasoningOnly": "El modelo solo razonó y no llegó a escribir una respuesta. Inténtalo de nuevo o elige otro modelo en los ajustes de IA.",
       "errorDemo": "En la demo, el Coach no responde.",
       "errorNoProvider": "El coach lee tus datos de salud registrados y responde preguntas sobre ellos (no es consejo médico). HealthLog necesita un proveedor de IA para ello: conecta tu propia clave o un modelo local.",
       "errorNoProviderAction": "Conectar un proveedor de IA",

messages/fr.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Ton message contient des instructions qui cherchent à remplacer mes consignes. Je suis le coach HealthLog et je ne résume que tes propres données de santé. Reformule ta question dans ce cadre.",
       "errorBudget": "Tu as atteint la limite quotidienne du coach. Le quota se réinitialise à minuit dans ton fuseau horaire.",
       "errorProvider": "Le coach n’a pas pu joindre un fournisseur d’analyse maintenant. Réessaie dans un instant.",
+      "errorReasoningOnly": "Le modèle a seulement réfléchi, sans écrire de réponse. Réessaie ou choisis un autre modèle dans les réglages IA.",
       "errorDemo": "Dans la démo, le Coach ne répond pas.",
       "errorNoProvider": "Le coach lit tes données de santé enregistrées et répond aux questions à leur sujet (pas un avis médical). HealthLog a besoin d'un fournisseur d'IA pour cela : connecte ta propre clé ou un modèle local.",
       "errorNoProviderAction": "Connecter un fournisseur d'IA",

messages/it.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Nel tuo messaggio ci sono istruzioni che cercano di sovrascrivere le mie indicazioni. Sono il coach di HealthLog e riassumo solo i tuoi dati di salute: riformula la domanda in questo perimetro.",
       "errorBudget": "Hai raggiunto il limite giornaliero del coach. Il budget si reimposta a mezzanotte nel tuo fuso orario.",
       "errorProvider": "Il coach non è riuscito a contattare un provider di analisi ora. Riprova fra poco.",
+      "errorReasoningOnly": "Il modello ha solo ragionato senza scrivere una risposta. Riprova oppure scegli un altro modello nelle impostazioni IA.",
       "errorDemo": "Nella demo il Coach non risponde.",
       "errorNoProvider": "Il coach legge i tuoi dati di salute registrati e risponde a domande su di essi (non è consulenza medica). HealthLog ha bisogno di un provider IA per questo: collega la tua chiave o un modello locale.",
       "errorNoProviderAction": "Collega un provider IA",

messages/ko.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "제 지시를 덮어쓰려는 표현이 보였어요. 저는 HealthLog 코치이고 회원님의 건강 데이터만 정리해 드려요. 그 범위로 질문을 다시 적어 주세요.",
       "errorBudget": "오늘 코치 사용 한도에 도달했어요. 사용량은 내 시간대의 자정에 초기화돼요.",
       "errorProvider": "지금은 코치가 인사이트 제공자에 연결하지 못했어요. 잠시 후 다시 시도해 주세요.",
+      "errorReasoningOnly": "모델이 생각만 하고 답변을 쓰지 않았어요. 다시 시도하거나 AI 설정에서 다른 모델을 선택해 주세요.",
       "errorDemo": "데모에서는 코치가 답하지 않아요.",
       "errorNoProvider": "코치는 기록된 건강 데이터를 읽고 그에 대한 질문에 답해요(의학적 조언은 아니에요). 그러려면 HealthLog에 AI 제공자가 필요해요. 직접 발급한 키나 로컬 모델을 연결해 주세요.",
       "errorNoProviderAction": "AI 제공자 연결",

messages/nl.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Ik zie formuleringen die proberen mijn instructies te omzeilen. Ik ben de HealthLog Coach en vat alleen je eigen gezondheidsgegevens samen. Formuleer je vraag opnieuw binnen dat kader.",
       "errorBudget": "Je hebt de gebruikslimiet van de Coach voor vandaag bereikt. Het budget wordt om middernacht in jouw tijdzone vernieuwd.",
       "errorProvider": "De Coach kan op dit moment geen provider voor Inzichten bereiken. Probeer het zo opnieuw.",
+      "errorReasoningOnly": "Het model heeft alleen nagedacht en geen antwoord geschreven. Probeer het opnieuw of kies een ander model in de AI-instellingen.",
       "errorDemo": "De Coach geeft in de demo geen antwoord.",
       "errorNoProvider": "De Coach leest je vastgelegde gezondheidsgegevens en beantwoordt vragen daarover (geen medisch advies). Daarvoor heeft HealthLog een AI-provider nodig. Koppel je eigen sleutel of een lokaal model.",
       "errorNoProviderAction": "AI-provider koppelen",

messages/pl.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Twoja wiadomość zawiera instrukcje, które próbują nadpisać moje wytyczne. Jestem coachem HealthLog i podsumowuję wyłącznie twoje własne dane zdrowotne. Przeformułuj pytanie w tych ramach.",
       "errorBudget": "Osiągnięto dzienny limit coacha. Limit resetuje się o północy w Twojej strefie czasowej.",
       "errorProvider": "Coach nie mógł teraz skontaktować się z dostawcą analizy. Spróbuj za chwilę.",
+      "errorReasoningOnly": "Model tylko rozumował i nie napisał odpowiedzi. Spróbuj ponownie albo wybierz inny model w ustawieniach AI.",
       "errorDemo": "W wersji demo Coach nie odpowiada.",
       "errorNoProvider": "Coach czyta Twoje zapisane dane zdrowotne i odpowiada na pytania o nie (to nie porada medyczna). HealthLog potrzebuje do tego dostawcy AI: połącz własny klucz lub model lokalny.",
       "errorNoProviderAction": "Połącz dostawcę AI",

messages/pt-BR.json

@@ -3020,6 +3020,7 @@
       "refusalInjection": "Percebi uma formulação que tenta substituir minhas instruções. Sou o Coach do HealthLog e só resumo seus próprios dados de saúde. Reformule sua pergunta nesses termos.",
       "errorBudget": "Você atingiu o limite de uso do Coach hoje. O orçamento é renovado à meia-noite no seu fuso horário.",
       "errorProvider": "O Coach não conseguiu alcançar um provedor de Insights agora. Tente novamente em instantes.",
+      "errorReasoningOnly": "O modelo apenas raciocinou e não escreveu uma resposta. Tente novamente ou escolha outro modelo nas configurações de IA.",
       "errorDemo": "O Coach não responde na demonstração.",
       "errorNoProvider": "O Coach lê seus dados de saúde registrados e responde perguntas sobre eles (não é aconselhamento médico). O HealthLog precisa de um provedor de IA para isso. Conecte sua própria chave ou um modelo local.",
       "errorNoProviderAction": "Conectar um provedor de IA",

src/components/insights/coach-panel/__tests__/message-thread.test.tsx

@@ -817,6 +817,14 @@ describe("errorCodeToI18nKey", () => {
     );
   });
 
+  // #1276 — a model that only reasoned was reached; "try again in a
+  // moment" is the wrong advice for it.
+  it("maps coach.provider.reasoning_only to its own copy", () => {
+    expect(errorCodeToI18nKey("coach.provider.reasoning_only")).toBe(
+      "insights.coach.errorReasoningOnly",
+    );
+  });
+
   // v1.39 — a refused turn names its reason. The capability refusals carry
   // their code in `meta.errorCode`; each maps to copy that says what is off
   // and who can change it, never the generic "provider unavailable".

src/components/insights/coach-panel/chat-bubble.tsx

@@ -87,6 +87,11 @@ export function errorCodeToI18nKey(code: string): string {
       // the user to guided setup with a one-line explainer + a Settings
       // link rendered alongside the bubble copy.
       return "insights.coach.errorNoProvider";
+    case "coach.provider.reasoning_only":
+      // #1276 — the model was reached and answered with its reasoning
+      // only, even after being asked once more. "Try again in a moment"
+      // would be the wrong advice; the copy names what happened.
+      return "insights.coach.errorReasoningOnly";
     case "coach.provider.unavailable":
     case "coach.provider.empty":
     case "coach.stream":

src/lib/ai/coach/turn/__tests__/chain-failure-code.test.ts

@@ -0,0 +1,76 @@
+/**
+ * The `coach.provider.*` code a failed provider chain surfaces. #1276 — a
+ * chain whose every hop answered with reasoning and no reply gets its own
+ * code: "could not reach a provider, try again in a moment" is wrong for it,
+ * because the provider was reached and answered, just never with an answer.
+ */
+import { describe, expect, it } from "vitest";
+
+import type { FallbackHop } from "@/lib/ai/provider-runner";
+
+import { chainFailureCode, classifyBubblingProviderError } from "../errors";
+
+function hop(over: Partial<FallbackHop>): FallbackHop {
+  return {
+    providerType: "openai-compatible",
+    attempt: 1,
+    failureReason: "OpenAI-compatible gateway returned empty content",
+    httpStatus: 0,
+    ...over,
+  };
+}
+
+describe("chainFailureCode", () => {
+  it("names a chain that only ever reasoned", () => {
+    expect(
+      chainFailureCode({
+        attempts: [hop({ failureKind: "reasoning_only" })],
+        primaryCredentialExpired: false,
+      }),
+    ).toBe("coach.provider.reasoning_only");
+  });
+
+  it("stays generic when another hop failed for another reason", () => {
+    expect(
+      chainFailureCode({
+        attempts: [
+          hop({ failureKind: "reasoning_only" }),
+          hop({ attempt: 2, httpStatus: 503, failureKind: "http" }),
+        ],
+        primaryCredentialExpired: false,
+      }),
+    ).toBe("coach.provider.unavailable");
+  });
+
+  it("keeps the existing codes", () => {
+    expect(
+      chainFailureCode({
+        attempts: [hop({ httpStatus: 401 })],
+        primaryCredentialExpired: true,
+      }),
+    ).toBe("coach.provider.credential_expired");
+    expect(
+      chainFailureCode({
+        attempts: [hop({ httpStatus: 429 }), hop({ httpStatus: 429 })],
+        primaryCredentialExpired: false,
+      }),
+    ).toBe("coach.provider.rate_limited");
+    expect(
+      chainFailureCode({ attempts: [], primaryCredentialExpired: false }),
+    ).toBe("coach.provider.unavailable");
+  });
+});
+
+describe("classifyBubblingProviderError", () => {
+  it("names an un-wrapped reasoning-only reply", () => {
+    const err = Object.assign(new Error("returned empty content"), {
+      httpStatus: 0,
+      kind: "reasoning_only",
+      upstream: "openai-compatible",
+    });
+    expect(classifyBubblingProviderError(err)).toEqual({
+      code: "reasoning_only",
+      httpStatus: 0,
+    });
+  });
+});

src/lib/ai/coach/turn/errors.ts

@@ -8,9 +8,41 @@
  */
 import { annotate, getEvent } from "@/lib/logging/context";
 import { redactOptional, redactSecrets } from "@/lib/logging/redact";
+import type { AllProvidersFailedError } from "@/lib/ai/provider-runner";
 
 import type { TurnEmitter } from "./types";
 
+/**
+ * The `coach.provider.*` code for a provider chain where every hop failed.
+ *
+ *  - v1.11.0 — the person's PRIMARY provider failed auth-class (401/403):
+ *    the credential is dead, not the service, so the drawer deep-links to
+ *    reconnect (`credential_expired`).
+ *  - v1.4.25 — every hop landed on 429: transient, on the provider's side
+ *    (`rate_limited`).
+ *  - #1276 — every hop answered with reasoning and no reply, after the
+ *    client already asked once more (`reasoning_only`). The provider was
+ *    reached; "try again in a moment" is the wrong advice, and the thought
+ *    itself is never shown as the answer.
+ *  - Anything else: `unavailable`.
+ */
+export function chainFailureCode(
+  err: Pick<AllProvidersFailedError, "attempts" | "primaryCredentialExpired">,
+): string {
+  if (err.primaryCredentialExpired) return "coach.provider.credential_expired";
+  const { attempts } = err;
+  if (attempts.length > 0 && attempts.every((a) => a.httpStatus === 429)) {
+    return "coach.provider.rate_limited";
+  }
+  if (
+    attempts.length > 0 &&
+    attempts.every((a) => a.failureKind === "reasoning_only")
+  ) {
+    return "coach.provider.reasoning_only";
+  }
+  return "coach.provider.unavailable";
+}
+
 /**
  * v1.21.3 — classify a provider error that bubbled out of the chain runner
  * un-wrapped (i.e. not an `AllProvidersFailedError`). The provider clients tag
@@ -18,15 +50,17 @@ import type { TurnEmitter } from "./types";
  * provider failure that must surface a graceful `coach.provider.*` frame rather
  * than rethrow into an HTTP 500. Returns `null` for anything that is NOT a
  * recognisable provider error (a real server bug), so those keep the 500 +
- * GlitchTip path. Status mapping mirrors `AllProvidersFailedError`: 401/403 →
- * credential_expired, 429 → rate_limited, everything else → unavailable.
+ * GlitchTip path. Status mapping mirrors `chainFailureCode`: 401/403 →
+ * credential_expired, 429 → rate_limited, a reasoning-only reply →
+ * reasoning_only, everything else → unavailable.
  */
 export function classifyBubblingProviderError(err: unknown): {
-  code: "credential_expired" | "rate_limited" | "unavailable";
+  code:
+    "credential_expired" | "rate_limited" | "reasoning_only" | "unavailable";
   httpStatus: number | null;
 } | null {
   if (err === null || typeof err !== "object") return null;
-  const e = err as { upstream?: unknown; httpStatus?: unknown };
+  const e = err as { upstream?: unknown; httpStatus?: unknown; kind?: unknown };
   const hasUpstreamTag = typeof e.upstream === "string";
   const status = typeof e.httpStatus === "number" ? e.httpStatus : null;
   // Require the wire tag — a bare `{ httpStatus }` from unrelated code must not
@@ -36,6 +70,10 @@ export function classifyBubblingProviderError(err: unknown): {
     return { code: "credential_expired", httpStatus: status };
   }
   if (status === 429) return { code: "rate_limited", httpStatus: status };
+  // #1276 — the empty-reply sentinel of a reply that was reasoning only.
+  if (e.kind === "reasoning_only") {
+    return { code: "reasoning_only", httpStatus: status };
+  }
   return { code: "unavailable", httpStatus: status };
 }
 

src/lib/ai/coach/turn/model.ts

@@ -85,7 +85,7 @@ import type { TurnLedger } from "./budget";
 import type { TurnReasoning } from "./reasoning";
 import type { TurnChain } from "./chain";
 import type { TurnContext } from "./context";
-import { classifyBubblingProviderError } from "./errors";
+import { chainFailureCode, classifyBubblingProviderError } from "./errors";
 import { snapshotStep, toStep } from "./steps";
 import type { TurnEmitter } from "./types";
 
@@ -769,29 +769,9 @@ export async function runTurnModel(args: {
           credentialExpired: err.primaryCredentialExpired,
         },
       });
-      // v1.11.0 — when the user's PRIMARY provider failed with an
-      // auth-class status (401/403), the credential is dead, not the
-      // service. Surface a distinct `credential_expired` frame so the
-      // drawer can deep-link the user to reconnect rather than telling
-      // them to "try again later" — the gap that let an expired codex
-      // token silently kill all generation.
-      if (err.primaryCredentialExpired) {
-        return { ok: false, code: "coach.provider.credential_expired" };
-      }
-      // v1.4.25 — distinguish provider rate-limit (every attempt
-      // landed on 429) from generic unavailability. The drawer's
-      // error-decoder surfaces the rate-limit copy with a warning
-      // toast instead of the generic provider-down message, so the
-      // user understands the limit is transient.
-      const allRateLimited =
-        err.attempts.length > 0 &&
-        err.attempts.every((a) => a.httpStatus === 429);
-      return {
-        ok: false,
-        code: allRateLimited
-          ? "coach.provider.rate_limited"
-          : "coach.provider.unavailable",
-      };
+      // Credential expired, rate limited, reasoning without an answer
+      // (#1276), or unavailable: `chainFailureCode` says which and why.
+      return { ok: false, code: chainFailureCode(err) };
     }
     // v1.21.3 — defence in depth. The chain runner wraps every hard provider
     // failure in `AllProvidersFailedError`, but a provider client can still