You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
TelemetryArea: what it touches
ImprovementsKind: in v2.1.275,
ImprovementsSection of the release
What
When otelHeadersHelper (a user-supplied command that generates rotating OpenTelemetry headers) fails, Claude Code now records exactly why. Errors are classified into one of eight kinds: timeout, bad exit code, killed, failed to spawn, empty output, invalid JSON, output that isn't an object, or a non-string value inside it. Each failure is reported through a new event, tengu_otel_headers_helper_failed, that includes the failure kind and exit code, and is also broadcast so anything watching can react to it. The helper is now also fetched in the background ahead of time rather than only on demand.
Why
This makes it much easier to diagnose why a custom OpenTelemetry header command isn't working, since the failure is now categorized instead of surfacing as a generic error.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up otelHeadersHelper, on Error reference.| `otelHeadersHelper failed; telemetry is not being exported. See /status: ...` | [Configuration warnings](#otelheadershelper-failed) |errorssee the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up otelHeadersHelper, on Error reference.
Anthropic's release notes agreeAdded a startup warning when a configured otelHeadersHelper fails, so sessions that silently export no telemetry are noticed
