chore(obs): [DRAFT-TRACE] logs on bench draft fallback paths

src/lib/snapshot.ts

@@ -139,21 +139,27 @@ export async function readSnapshot(
         signal: AbortSignal.timeout(2_000),
       },
     );
-    if (!res.ok) return null;
+    if (!res.ok) {
+      console.warn(`[DRAFT-TRACE] kv_http slug=${slug} status=${res.status}`);
+      return null;
+    }
     const env = (await res.json()) as { result?: string | null };
-    if (!env.result) return null;
+    if (!env.result) {
+      console.warn(`[DRAFT-TRACE] kv_empty slug=${slug} (no snapshot ever written)`);
+      return null;
+    }
     const raw = JSON.parse(env.result);
     const parsed = SnapshotSchema.safeParse(raw);
     if (!parsed.success) {
       console.warn(
-        `snapshot.read rejected (shape) for ${slug}: ${parsed.error.message}`,
+        `[DRAFT-TRACE] kv_shape slug=${slug} err=${parsed.error.message}`,
       );
       return null;
     }
     const age = Date.now() - parsed.data.savedAt;
     if (age > MAX_SNAPSHOT_AGE_MS) {
       console.warn(
-        `snapshot.read rejected (stale ${Math.round(age / 1000 / 60)}m) for ${slug}`,
+        `[DRAFT-TRACE] kv_stale slug=${slug} age_min=${Math.round(age / 1000 / 60)}`,
       );
       return null;
     }
@@ -164,11 +170,13 @@ export async function readSnapshot(
       lastRunAt: parsed.data.lastRunAt,
     };
   } catch (err) {
-    console.warn(
-      `snapshot.read failed for ${slug}: ${
-        err instanceof Error ? err.message : String(err)
-      }`,
-    );
+    const msg = err instanceof Error ? err.message : String(err);
+    // Distinguish abort/timeout (most common) from other network errors so
+    // the post-incident grep can see if it's KV slowness vs KV down.
+    const tag = msg.toLowerCase().includes("abort") || msg.toLowerCase().includes("timeout")
+      ? "kv_timeout"
+      : "kv_neterr";
+    console.warn(`[DRAFT-TRACE] ${tag} slug=${slug} err=${msg}`);
     return null;
   }
 }

src/lib/spec.ts

@@ -42,7 +42,9 @@ const loadBenchmarkUnfilteredCached = unstable_cache(
     const specs = await loadSpecs();
     const spec = specs.find((s) => s.slug === slug);
     if (!spec) return undefined;
+    const promStart = Date.now();
     const bench = await specToBenchmark(spec);
+    const promMs = Date.now() - promStart;
     if (spec.status === "live" && bench.status === "draft") {
       // Live spec, but Prom returned nothing this cycle. Try the
       // persistent snapshot before giving up. This is the cold-start
@@ -51,8 +53,18 @@ const loadBenchmarkUnfilteredCached = unstable_cache(
       // good data; without KV we throw to preserve any previous cache
       // value (or eventually fall through to the draft placeholder in
       // the aggregator).
+      // [DRAFT-TRACE] temporary observability — remove once we've pinned
+      // the cause of intermittent draft renders.
+      console.warn(
+        `[DRAFT-TRACE] collapse slug=${slug} prom_ms=${promMs} → trying KV snapshot`,
+      );
+      const kvStart = Date.now();
       const snap = await readSnapshot(slug);
+      const kvMs = Date.now() - kvStart;
       if (snap) {
+        console.warn(
+          `[DRAFT-TRACE] kv_hit slug=${slug} kv_ms=${kvMs} → serving snapshot`,
+        );
         const editorial = buildEditorial(spec);
         const reconstructed = renderBenchmarkText({ ...editorial, ...snap });
         // The reconstructed bench is live data, just sourced from KV
@@ -63,6 +75,9 @@ const loadBenchmarkUnfilteredCached = unstable_cache(
         }
         return reconstructed;
       }
+      console.warn(
+        `[DRAFT-TRACE] kv_miss slug=${slug} kv_ms=${kvMs} → throwing to keep prev cache`,
+      );
       throw new Error(
         `loadBenchmark(${slug}): live spec collapsed to draft, keeping prev cache`,
       );
@@ -99,6 +114,13 @@ const loadAllBenchmarksCached = unstable_cache(
         // to. Surface a placeholder so the page still renders rather
         // than dropping the bench from the list (which would break the
         // sitemap, the products pages, and the "More benchmarks" rail).
+        // [DRAFT-TRACE] this is the path that produces a visible "draft"
+        // render to the user — log so we can correlate with KV / prom state.
+        const reason =
+          r.status === "rejected" ? (r.reason instanceof Error ? r.reason.message : String(r.reason)) : "no_value";
+        console.warn(
+          `[DRAFT-TRACE] placeholder_used slug=${spec.slug} reason=${reason}`,
+        );
         benchmarks.push(draftPlaceholderForSpec(spec));
       }
     }