Receive OTLP metrics containing AI usage data (tokens, costs). Accepts both application/json (shown below) and application/x-protobuf (used by default by the standard OpenTelemetry SDKs; refer to the OTLP spec). Provider is auto-detected from resource attributes. Note: Claude Code metrics are intentionally not processed and produce no records — Claude Code's per-call cost and token data is captured via the /v1/logs endpoint instead. Sending Claude Code metric payloads here is harmless but yields processedEvents=0.