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fix: measure firstResponseMs on first NDJSON line, not first tool_use #789

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fix: measure firstResponseMs on first NDJSON line, not first tool_use #789

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d82f01e
Merge pull request #1 from garrytan/main
km-git007 Apr 3, 2026
6cc0859
fix: measure firstResponseMs on first NDJSON line, not first tool_use
Apr 3, 2026
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8 changes: 6 additions & 2 deletions test/helpers/session-runner.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -209,6 +209,11 @@ export async function runSkillTest(options: {
if (!line.trim()) continue;
collectedLines.push(line);

// Track time to first NDJSON line (measures latency from spawn to first Claude response)
if (firstResponseMs === 0) {
firstResponseMs = Date.now() - startTime;
}

// Real-time progress to stderr + persistent logs
try {
const event = JSON.parse(line);
Expand All @@ -220,8 +225,7 @@ export async function runSkillTest(options: {
liveToolCount++;
const now = Date.now();
const elapsed = Math.round((now - startTime) / 1000);
// Track timing telemetry
if (firstResponseMs === 0) firstResponseMs = now - startTime;
// Track inter-turn latency (tool call to tool call)
if (lastToolTime > 0) {
const interTurn = now - lastToolTime;
if (interTurn > maxInterTurnMs) maxInterTurnMs = interTurn;
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