Claude Code v2.1.221 ·
Background attach telemetry gets cold-start and surface dimensions
Background attach events now record cold starts, surface and first frame details.
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
TelemetryArea: what it touches
Internal ChangesKind: in v2.1.221,
Internal ChangesSection of the release
Details
- New attributes:
attach_cold, daemon_booted, first_frame_kind, surface, a validated via, plus message-count fields. - Those attribute names were added to the low-cardinality attribute allowlist.
via is now filtered against a fixed set (starting, running, resuming and so on) rather than passed through as-is.
Evidence
first_frame_kind
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
See this entry in the whole of v2.1.221 →
