diff --git a/open-sse/services/tokenRefresh.ts b/open-sse/services/tokenRefresh.ts
index 507e9ff27b..2528c167bc 100755
--- a/open-sse/services/tokenRefresh.ts
+++ b/open-sse/services/tokenRefresh.ts
@@ -50,9 +50,22 @@ export const REFRESH_LEAD_MS: Record<string, number> = {
 
 /**
  * Get the proactive refresh lead time (ms) for a given provider.
- * Falls back to TOKEN_EXPIRY_BUFFER_MS (5 min) when not explicitly listed.
+ *
+ * Precedence:
+ *   1. A per-connection override in `providerSpecificData.refreshLeadMs`
+ *      (must be a positive finite number), so an operator can tune the lead
+ *      time for a single connection without touching the provider defaults.
+ *   2. The provider default from REFRESH_LEAD_MS.
+ *   3. TOKEN_EXPIRY_BUFFER_MS (5 min) when nothing else applies.
  */
-export function getRefreshLeadMs(provider: string): number {
+export function getRefreshLeadMs(
+  provider: string,
+  providerSpecificData?: { refreshLeadMs?: unknown } | null
+): number {
+  const override = providerSpecificData?.refreshLeadMs;
+  if (typeof override === "number" && Number.isFinite(override) && override > 0) {
+    return override;
+  }
   return REFRESH_LEAD_MS[provider] ?? TOKEN_EXPIRY_BUFFER_MS;
 }
 
diff --git a/src/sse/services/tokenRefresh.ts b/src/sse/services/tokenRefresh.ts
index 63415b09b0..ab51be2742 100755
--- a/src/sse/services/tokenRefresh.ts
+++ b/src/sse/services/tokenRefresh.ts
@@ -174,7 +174,7 @@ export async function checkAndRefreshToken(provider: string, credentials: any) {
   if (updatedCredentials.expiresAt) {
     const expiresAt = new Date(updatedCredentials.expiresAt).getTime();
     const now = Date.now();
-    const refreshLead = _getRefreshLeadMs(provider);
+    const refreshLead = _getRefreshLeadMs(provider, updatedCredentials.providerSpecificData);
 
     if (expiresAt - now < refreshLead) {
       log.info("TOKEN_REFRESH", "Token expiring soon, refreshing proactively", {
diff --git a/tests/unit/service-token-refresh.test.ts b/tests/unit/service-token-refresh.test.ts
index f254d54e7d..42622907fe 100644
--- a/tests/unit/service-token-refresh.test.ts
+++ b/tests/unit/service-token-refresh.test.ts
@@ -17,6 +17,32 @@ describe("tokenRefresh helpers", () => {
       assert.equal(mod.getRefreshLeadMs("unknown-provider"), mod.TOKEN_EXPIRY_BUFFER_MS);
       assert.equal(mod.getRefreshLeadMs(""), mod.TOKEN_EXPIRY_BUFFER_MS);
     });
+
+    it("honors a positive per-connection refreshLeadMs override", () => {
+      // Override beats both the provider default and the fallback buffer.
+      assert.equal(mod.getRefreshLeadMs("codex", { refreshLeadMs: 90_000 }), 90_000);
+      assert.equal(
+        mod.getRefreshLeadMs("unknown-provider", { refreshLeadMs: 12_345 }),
+        12_345
+      );
+    });
+
+    it("ignores invalid or non-positive override values", () => {
+      // Falls through to provider default / buffer when the override is unusable.
+      assert.equal(mod.getRefreshLeadMs("codex", null), 5 * 60 * 1000);
+      assert.equal(mod.getRefreshLeadMs("codex", {}), 5 * 60 * 1000);
+      assert.equal(mod.getRefreshLeadMs("codex", { refreshLeadMs: 0 }), 5 * 60 * 1000);
+      assert.equal(mod.getRefreshLeadMs("codex", { refreshLeadMs: -1 }), 5 * 60 * 1000);
+      assert.equal(
+        mod.getRefreshLeadMs("codex", { refreshLeadMs: "60000" as unknown as number }),
+        5 * 60 * 1000
+      );
+      assert.equal(mod.getRefreshLeadMs("codex", { refreshLeadMs: NaN }), 5 * 60 * 1000);
+      assert.equal(
+        mod.getRefreshLeadMs("unknown-provider", { refreshLeadMs: -5 }),
+        mod.TOKEN_EXPIRY_BUFFER_MS
+      );
+    });
   });
 
   describe("supportsTokenRefresh", () => {