Vitest declares `@opentelemetry/api` as an optional peer dependency, which it uses internally to generate spans. When trace collection is not enabled, Vitest will not attempt to use this dependency.

When configuring Vitest to use OpenTelemetry, you will typically install `@opentelemetry/sdk-node`, which includes `@opentelemetry/api` as a transitive dependency, thereby satisfying Vitest's peer dependency requirement. If you encounter an error indicating that `@opentelemetry/api` cannot be found, this typically means trace collection has not been enabled. If the error persists after proper configuration, you may need to install `@opentelemetry/api` explicitly.

## Inter-Process Context Propagation

Vitest supports automatic context propagation from parent processes via the `TRACEPARENT` and `TRACESTATE` environment variables as defined in the [OpenTelemetry specification](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/context/env-carriers.md). This is particularly useful when running Vitest as part of a larger distributed tracing system (e.g., CI/CD pipelines with OpenTelemetry instrumentation).