diff --git a/src/codex/catalog/sync.ts b/src/codex/catalog/sync.ts
index 877c18471..3189c1e73 100644
--- a/src/codex/catalog/sync.ts
+++ b/src/codex/catalog/sync.ts
@@ -329,9 +329,11 @@ export function mergeCatalogEntriesForSync(
   multiAgentMode: MultiAgentMode = "default",
   exactComboSlugs: ReadonlySet<string> = new Set(),
   hasPhysicalComboProvider = false,
+  includeNativeOpenAi = true,
 ): RawEntry[] {
   const rank = new Map(featured.map((slug, i) => [slug, i] as const));
-  const native = catalogModels
+  const native = includeNativeOpenAi
+    ? catalogModels
     .filter(m => typeof m.slug === "string"
       && !(m.slug as string).includes("/")
       && m.owned_by !== COMBO_NAMESPACE
@@ -367,11 +369,14 @@ export function mergeCatalogEntriesForSync(
       // for subagent max spawns; wire-clamped to the model's real top rung).
       if (!isGpt56NativeSlug(slug)) ensureUltraReasoningLevel(preserved);
       return preserved;
-    });
+    })
+    : [];
 
   // Backfill any native OpenAI slug that the on-disk catalog is missing (e.g. gpt-5.5), so a
   // routed provider exposing the same id can never delete the native OpenAI/Codex base row.
+  // Skip when no enabled canonical openai provider exists (#636) — bare gpt-* would 404.
   const nativeSlugs = new Set(native.flatMap(m => typeof m.slug === "string" ? [m.slug] : []));
+  if (includeNativeOpenAi) {
   for (const slug of nativeOpenAiSlugs()) {
     if (nativeSlugs.has(slug)) continue;
     nativeSlugs.add(slug);
@@ -382,6 +387,7 @@ export function mergeCatalogEntriesForSync(
         : 9;
     native.push(deriveEntry(template ? JSON.parse(JSON.stringify(template)) : null, slug, "OpenAI native model (Codex OAuth passthrough).", priority));
   }
+  }
 
   const freshSlugs = new Set(
     routedEntries.flatMap(entry => typeof entry.slug === "string" ? [entry.slug] : []),
@@ -497,7 +503,16 @@ export async function syncCatalogModels(config: OcxConfig): Promise<{
   // native AND routed so the advertised flag matches the implemented endpoint (phase 120.4) and a
   // native template can never leak supports_websockets while the flag is off.
   const wsEnabled = websocketsEnabled(config);
-  catalog.models = mergeCatalogEntriesForSync(catalog.models ?? [], goEntries, baseline, featured, wsEnabled, goIds, template, disabledNativeSlugs(config), gatheredProviderNames, multiAgentMode, exactComboSlugs, hasPhysicalComboProvider);
+  const enabledProviders = Object.entries(config.providers ?? {})
+    .filter(([, prov]) => prov.disabled !== true);
+  const hasCanonicalOpenai = enabledProviders.some(([name, prov]) =>
+    name === "openai" && isCanonicalOpenAiForwardProvider(prov),
+  );
+  // #636: when the user only configured non-OpenAI providers (e.g. kimi), do not advertise
+  // bare gpt-* rows that hard-404 via NoEnabledOpenAiProviderError. Keep natives when no
+  // providers are configured yet (fresh install / catalog bootstrap tests).
+  const includeNativeOpenAi = enabledProviders.length === 0 || hasCanonicalOpenai;
+  catalog.models = mergeCatalogEntriesForSync(catalog.models ?? [], goEntries, baseline, featured, wsEnabled, goIds, template, disabledNativeSlugs(config), gatheredProviderNames, multiAgentMode, exactComboSlugs, hasPhysicalComboProvider, includeNativeOpenAi);
   clampCatalogModelsToCodexSupport(catalog.models);
 
   atomicWriteFile(catalogPath, JSON.stringify(catalog, null, 2) + "\n");
diff --git a/src/router.ts b/src/router.ts
index 6dc331f4d..b20ef7f12 100644
--- a/src/router.ts
+++ b/src/router.ts
@@ -293,7 +293,10 @@ function activeProviderEntries(config: OcxConfig): [string, OcxProviderConfig][]
 
 export class NoEnabledOpenAiProviderError extends Error {
   constructor(modelId: string) {
-    super(`No enabled OpenAI provider for model: ${modelId}. Run 'ocx init' to configure a provider, or check that your config has an enabled 'openai' provider.`);
+    super(
+      `Model ${modelId} requires the canonical openai provider. `
+      + `Run: ocx provider add openai && ocx sync && ocx restart`,
+    );
     this.name = "NoEnabledOpenAiProviderError";
   }
 }
diff --git a/tests/router.test.ts b/tests/router.test.ts
index 82cf6cb5b..ac6fe6d7e 100644
--- a/tests/router.test.ts
+++ b/tests/router.test.ts
@@ -142,9 +142,9 @@ describe("routeModel registry effort defaults", () => {
     expect(routeModel({ ...base, providers: { ...base.providers, openai: { ...forward, codexAccountMode: "direct" } } }, "gpt-5.5"))
       .toMatchObject({ providerName: "openai", codexAccountMode: "direct" });
     expect(() => routeModel({ ...base, providers: { ...base.providers, openai: { ...forward, disabled: true } } }, "gpt-5.5"))
-      .toThrow(NoEnabledOpenAiProviderError);
+      .toThrow(/requires the canonical openai provider/);
     const unavailable = { ...base, providers: { "openai-proxy": base.providers["openai-proxy"] } };
-    expect(() => routeModel(unavailable, "gpt-5.5")).toThrow(NoEnabledOpenAiProviderError);
+    expect(() => routeModel(unavailable, "gpt-5.5")).toThrow(/ocx provider add openai/);
   });
 
   test("rejects legacy chatgpt namespaces even when configured", () => {