Observability

Paperclip ships with opt-in OpenTelemetry auto-instrumentation for the server process. When activated it produces traces only — no metrics and no logs are exported by this integration. The OTel packages are optional peer dependencies: they are not in the default lockfile and are loaded dynamically only when an operator turns the feature on.

When OTEL_EXPORTER_OTLP_ENDPOINT is unset, none of the @opentelemetry/* packages are imported and there is zero runtime overhead.

Enabling tracing

1. Install the OTel peer dependencies

Install the SDK, the auto-instrumentations bundle, the resources/semconv helpers, and one exporter matching your chosen OTLP protocol.

Common to every protocol:

bash

pnpm add \
  @opentelemetry/sdk-node \
  @opentelemetry/auto-instrumentations-node \
  @opentelemetry/resources \
  @opentelemetry/semantic-conventions

Then add the exporter for the protocol you intend to use:

`OTEL_EXPORTER_OTLP_PROTOCOL`	Exporter package
`grpc` (default if unset)	`@opentelemetry/exporter-trace-otlp-grpc`
`http/protobuf`	`@opentelemetry/exporter-trace-otlp-proto`
`http/json`	`@opentelemetry/exporter-trace-otlp-http`

For example, for the default gRPC path:

bash

pnpm add @opentelemetry/exporter-trace-otlp-grpc

2. Set the environment

Minimal setup:

bash

# Required — turns the feature on. Point at your collector.
# For grpc this is the gRPC target (typically port 4317). For the HTTP
# protocols give the collector's BASE URL (typically port 4318) — the
# exporter appends /v1/traces itself.
export OTEL_EXPORTER_OTLP_ENDPOINT="http://otel-collector:4317"

# Optional — protocol. Defaults to grpc when unset.
# Valid values: grpc | http/protobuf | http/json
export OTEL_EXPORTER_OTLP_PROTOCOL="grpc"

# Optional — service identity attached to every span.
export OTEL_SERVICE_NAME="paperclip"
export OTEL_SERVICE_VERSION="2026.5.0"

If OTEL_EXPORTER_OTLP_PROTOCOL is set to an unrecognized value, Paperclip logs a single warning and falls back to gRPC.

If OTEL_EXPORTER_OTLP_ENDPOINT is set but the OTel packages are not installed, the server logs a single diagnostic line on boot and continues without tracing — your server stays up.

Scope

This integration emits traces only. Metrics and log exporters are out of scope and intentionally not configured here. Auto-instrumentations for fs, dns, and net are disabled by default because they are too chatty for this workload; everything else from @opentelemetry/auto-instrumentations-node is on (HTTP, Express, PG, etc.).