diff --git a/src/app/api/v1/models/route.js b/src/app/api/v1/models/route.js
index 32647304..f2451faf 100644
--- a/src/app/api/v1/models/route.js
+++ b/src/app/api/v1/models/route.js
@@ -79,8 +79,9 @@ const parseOpenAIStyleModels = (data) => {
   return data?.data || data?.models || data?.results || [];
 };
 
-// Matches provider IDs that are upstream/cross-instance connections (contain a UUID suffix)
-const UPSTREAM_CONNECTION_RE = /[-_][0-9a-f]{8,}$/i;
+// Header sent by fetchCompatibleModelIds to detect cross-instance /models fetches
+// and break recursive loops between 9router instances connected to each other.
+const INTERNAL_MODELS_FETCH_HEADER = "x-9r-internal-models-fetch";
 
 // LLM kind sentinel — combos/models with no explicit kind default to LLM
 const LLM_KIND = "llm";
@@ -145,7 +146,7 @@ async function fetchCompatibleModelIds(connection) {
     const timeoutId = setTimeout(() => controller.abort(), 5000);
     const response = await fetch(url, {
       method: "GET",
-      headers,
+      headers: { ...headers, [INTERNAL_MODELS_FETCH_HEADER]: "1" },
       cache: "no-store",
       signal: controller.signal,
     });
@@ -189,7 +190,11 @@ function comboMatchesKinds(combo, kindFilter) {
  * Build OpenAI-format models list filtered by service kinds.
  * @param {string[]} kindFilter - List of service kinds to include (e.g. ["llm"], ["webSearch","webFetch"]).
  */
-export async function buildModelsList(kindFilter) {
+export async function buildModelsList(kindFilter, options = {}) {
+  // When this header is present, the /v1/models request came from another
+  // 9router instance's fetchCompatibleModelIds — skip dynamic fetch to break
+  // cross-instance recursive loops.
+  const skipDynamicFetch = options.skipDynamicFetch === true;
   let connections = [];
   try {
     connections = await getProviderConnections();
@@ -319,7 +324,7 @@ export async function buildModelsList(kindFilter) {
           )
         : providerModels.map((model) => model.id);
 
-      if (isCompatibleProvider && rawModelIds.length === 0 && !UPSTREAM_CONNECTION_RE.test(providerId)) {
+      if (isCompatibleProvider && rawModelIds.length === 0 && !skipDynamicFetch) {
         rawModelIds = await fetchCompatibleModelIds(conn);
       }
 
@@ -475,9 +480,11 @@ export async function OPTIONS() {
  * GET /v1/models - OpenAI compatible models list (LLM/chat models only by default).
  * For other capabilities use /v1/models/{kind} (image, tts, stt, embedding, image-to-text, web).
  */
-export async function GET() {
+export async function GET(request) {
   try {
-    const data = await buildModelsList([LLM_KIND]);
+    // Detect cross-instance recursive /models fetch (another 9router fetching our /models)
+    const skipDynamicFetch = request?.headers?.get(INTERNAL_MODELS_FETCH_HEADER) === "1";
+    const data = await buildModelsList([LLM_KIND], { skipDynamicFetch });
     return Response.json({ object: "list", data }, {
       headers: { "Access-Control-Allow-Origin": "*" },
     });