From 2b1319b9372f4996f5b26da8eb79ea73d36a6038 Mon Sep 17 00:00:00 2001
From: Runloop Agent <agent@runloop.ai>
Date: Tue, 17 Mar 2026 19:03:34 +0000
Subject: [PATCH] perf(bmj): parallelize scenario run fetching and name
 resolution in logs

Replace serial per-agent listBenchmarkRunScenarioRuns loop with
Promise.allSettled so all agents fetch in parallel. Also parallelize
resolveScenarioName calls with Promise.all. This makes loading time
proportional to the slowest single agent rather than the sum of all agents.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/commands/benchmark-job/logs.ts | 74 +++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 28 deletions(-)

diff --git a/src/commands/benchmark-job/logs.ts b/src/commands/benchmark-job/logs.ts
index 818a3b8..aa6f62a 100644
--- a/src/commands/benchmark-job/logs.ts
+++ b/src/commands/benchmark-job/logs.ts
@@ -302,41 +302,59 @@ export async function downloadBenchmarkJobLogs(
     // Build scenario outcome lookup from completed outcomes
     const outcomeMap = buildScenarioOutcomeMap(job);
 
-    // Gather all scenario log targets across benchmark runs
-    const targets: ScenarioLogTarget[] = [];
-
-    for (const run of runs) {
-      const agentLabel = run.modelName
-        ? `${run.agentName}:${run.modelName}`
-        : run.agentName;
-      console.log(
-        chalk.dim(`Fetching scenario runs for agent "${agentLabel}"...`),
-      );
-      let scenarioRuns = await listBenchmarkRunScenarioRuns(run.benchmarkRunId);
-
-      // Apply --scenario filter
+    // Gather all scenario log targets across benchmark runs, fetching all
+    // agents' scenario run lists in parallel for speed.
+    console.log(
+      chalk.dim(
+        `Fetching scenario runs for ${runs.length} agent(s) in parallel...`,
+      ),
+    );
+
+    const agentScenarioRuns = await Promise.allSettled(
+      runs.map((run) => listBenchmarkRunScenarioRuns(run.benchmarkRunId)),
+    );
+
+    // Collect (run, scenarioRun) pairs, applying --scenario filter
+    const pairs: { run: BenchmarkRunInfo; sr: ScenarioRun }[] = [];
+    for (let i = 0; i < runs.length; i++) {
+      const result = agentScenarioRuns[i];
+      if (result.status === "rejected") {
+        const agentLabel = runs[i].modelName
+          ? `${runs[i].agentName}:${runs[i].modelName}`
+          : runs[i].agentName;
+        console.error(
+          chalk.yellow(
+            `  Warning: failed to fetch scenario runs for agent "${agentLabel}": ${result.reason}`,
+          ),
+        );
+        continue;
+      }
+      let scenarioRuns = result.value;
       if (options.scenario) {
         scenarioRuns = scenarioRuns.filter((sr) => sr.id === options.scenario);
       }
-
       for (const sr of scenarioRuns) {
-        const scenarioName = await resolveScenarioName(
-          sr.id,
-          sr.scenario_id,
-          outcomeMap,
-        );
-        targets.push({
-          agentName: run.agentName,
-          modelName: run.modelName,
-          scenarioName,
-          scenarioRunId: sr.id,
-          scenarioRun: sr,
-          outcome: outcomeMap.get(sr.id),
-          destDir: "", // assigned below
-        });
+        pairs.push({ run: runs[i], sr });
       }
     }
 
+    // Resolve all scenario names in parallel (may hit the API for in-progress runs)
+    const resolvedNames = await Promise.all(
+      pairs.map(({ sr }) =>
+        resolveScenarioName(sr.id, sr.scenario_id, outcomeMap),
+      ),
+    );
+
+    const targets: ScenarioLogTarget[] = pairs.map(({ run, sr }, i) => ({
+      agentName: run.agentName,
+      modelName: run.modelName,
+      scenarioName: resolvedNames[i],
+      scenarioRunId: sr.id,
+      scenarioRun: sr,
+      outcome: outcomeMap.get(sr.id),
+      destDir: "", // assigned below
+    }));
+
     if (targets.length === 0) {
       console.log(chalk.yellow("No scenario runs found to download logs for."));
       return;