A restored node whose source run is gone says its curve was lost

The run detail works out curve_lost per node when read, from whether its
cached_from run still exists. The run page names the deleted run in place
of the generic NO_CURVE note.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WgBfkm4rCmtd1T4vHWjEPx

frontend/src/components/Runs/RunDetail.tsx

@@ -22,10 +22,10 @@ import { MetricPicker, RunMetricChart, useMetricNames } from "./MetricChart"
 import { OpenInDashboard } from "./OpenInDashboard"
 import {
   CARD,
+  curveLost,
   downloadArtifact,
   FLOW_GONE,
   isLive,
-  NO_CURVE,
   paramText,
   runQueryOptions,
   shortCommit,
@@ -53,10 +53,9 @@ export function RunDetail({ id }: { id: string }) {
   const nodes = run.nodes ?? []
   const artifacts = run.artifacts ?? []
   const reason = statusReason(run)
-  // A restored node's curve comes from the run it was restored from, so an
-  // empty chart here means that run is gone rather than that this one failed.
-  // Said once, where it applies.
-  const cached = nodes.some((node) => node.status === "cached")
+  // A restored node's curve comes from the run it was restored from, so it
+  // goes when that run is deleted. Said once, where it applies.
+  const lost = nodes.filter((node) => node.curve_lost)
 
   // What the flow declared when this run was submitted. A run from before
   // that was kept reads against the flow's current declarations.
@@ -206,8 +205,10 @@ export function RunDetail({ id }: { id: string }) {
         </section>
       )}
 
-      {names.length === 0 && cached && (
-        <p className={cn(CARD, "text-muted-foreground text-sm")}>{NO_CURVE}</p>
+      {lost.length > 0 && (
+        <p className={cn(CARD, "text-muted-foreground text-sm")}>
+          {curveLost(lost)}
+        </p>
       )}
 
       {Object.keys(run.result ?? {}).length > 0 && (

frontend/src/components/Runs/queries.ts

@@ -285,6 +285,20 @@ export async function cancelThenDelete(runId: string) {
 export const NO_CURVE =
   "No curve was recorded. A node restored from the cache is read back from the run that produced it, so this draws nothing once that run has been deleted — its outputs are still on the result."
 
+/**
+ * Which restored nodes lost their curve, and with which deleted run.
+ *
+ * Named, since a chart that is merely short a few lines says nothing.
+ */
+export function curveLost(nodes: { node: string; cached_from?: string }[]) {
+  const runs = [...new Set(nodes.map((one) => shortId(one.cached_from ?? "")))]
+  const which =
+    runs.length === 1
+      ? `run ${runs[0]}, which was`
+      : `runs ${runs.join(", ")}, which were`
+  return `The curve of ${nodes.map((one) => one.node).join(", ")} was lost with ${which} deleted. A node restored from the cache reads its curve from the run that recorded it. Its outputs are still on the result.`
+}
+
 /** Why a run can name a flow that is not there any more. */
 export const FLOW_GONE =
   "The flow this ran has been deleted. The run is kept as the record of what ran, but there is nothing left to retry it against."