Preserve last_failure_error across instance recreation, fix RDMA banner wording

- apply_instance_created no longer clears last_failure_error so the
  error context persists while the new instance starts up
- Dashboard retryError shows the error without (N/3) prefix when
  consecutiveFailures is 0 (instance was recreated)
- Jaccl warning tooltip now says "experimental RDMA driver in macOS"

Co-Authored-By: Claude Opus 4.6 <[email protected]>

dashboard/src/routes/+page.svelte

@@ -2067,7 +2067,7 @@
           >
             <p class="text-xs text-white/80 mb-2">
               A macOS RDMA driver error was detected. This is a known issue
-              with the experimental jaccl driver.
+              with the experimental RDMA driver in macOS.
             </p>
             <p class="text-xs text-white/60 mb-2">
               <span class="text-red-300">Error:</span>
@@ -2657,7 +2657,9 @@
                     : getMetaInstancePlacingStatus(id)}
                   {@const metaData = item.isMetaInstance ? metaInstancesData[id] : null}
                   {@const retryError = metaData?.lastFailureError && !downloadInfo.isFailed
-                    ? `(${((metaData.consecutiveFailures - 1) % 3) + 1}/3) ${metaData.lastFailureError}`
+                    ? metaData.consecutiveFailures > 0
+                      ? `(${((metaData.consecutiveFailures - 1) % 3) + 1}/3) ${metaData.lastFailureError}`
+                      : metaData.lastFailureError
                     : null}
                   {@const statusText = downloadInfo.statusText}
                   {@const isDownloading = downloadInfo.isDownloading}
@@ -3523,7 +3525,9 @@
                       : getMetaInstancePlacingStatus(id)}
                     {@const metaData = item.isMetaInstance ? metaInstancesData[id] : null}
                     {@const retryError = metaData?.lastFailureError && !downloadInfo.isFailed
-                      ? `(${((metaData.consecutiveFailures - 1) % 3) + 1}/3) ${metaData.lastFailureError}`
+                      ? metaData.consecutiveFailures > 0
+                        ? `(${((metaData.consecutiveFailures - 1) % 3) + 1}/3) ${metaData.lastFailureError}`
+                        : metaData.lastFailureError
                       : null}
                     {@const statusText = downloadInfo.statusText}
                     {@const isDownloading = downloadInfo.isDownloading}

src/exo/master/tests/test_reconcile.py

@@ -664,7 +664,7 @@ def test_apply_instance_retrying_skips_missing_runners():
 
 
 def test_apply_instance_created_resets_failure_counter():
-    """InstanceCreated resets consecutive_failures on the MetaInstance."""
+    """InstanceCreated resets consecutive_failures but preserves last_failure_error."""
     meta = _meta_instance().model_copy(
         update={"consecutive_failures": 3, "last_failure_error": "old error"}
     )
@@ -674,7 +674,7 @@ def test_apply_instance_created_resets_failure_counter():
     new_state = apply(state, IndexedEvent(idx=0, event=event))
     mi = new_state.meta_instances[meta.meta_instance_id]
     assert mi.consecutive_failures == 0
-    assert mi.last_failure_error is None
+    assert mi.last_failure_error == "old error"
     assert mi.placement_error is None
 
 

src/exo/shared/apply.py

@@ -210,7 +210,6 @@ def apply_instance_created(event: InstanceCreated, state: State) -> State:
                 instance.meta_instance_id,
                 placement_error=None,
                 consecutive_failures=0,
-                last_failure_error=None,
             )
     return state.model_copy(update=update)