Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.260 ·

New streaming latency telemetry fields on SDK turn results

SDK turn results now capture finer streaming latency timing for the first content frame.

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaHeadless SDKwhat it touches
KindInternal Changesin v2.1.260,
Under the hood

SDK turn results now capture finer streaming latency timing for the first content frame.

Headless SDK query results now capture finer-grained streaming latency: first_content_frame_ms and timing for when the first stream chunk was posted/acknowledged, including wall-clock variants, added alongside the existing ttft metrics.

Read from
Names in the bundlefirst_content_frame_ms
What the documentation says

See this entry in the whole of v2.1.260 →