diff --git a/FAQ.md b/FAQ.md
index 8e1895d..3c762e7 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -59,7 +59,7 @@ ColdBrew generates a unique trace ID for every request automatically. It can als
 1. **HTTP header** — `x-trace-id` (configurable via `TRACE_HEADER_NAME`) is forwarded from the HTTP gateway to gRPC
 2. **Proto field** — if your request message has a `trace_id` string field, ColdBrew reads it via the generated `GetTraceId()` method
 
-The trace ID is then propagated to structured logs (`"trace": "abc123"`) and Sentry/Rollbar error reports — so you can search for one ID and find the complete request flow across your logs and error tracking.
+The trace ID is then propagated to structured logs (`"trace": "abc123"`), Sentry/Rollbar error reports, and OpenTelemetry spans (as the `coldbrew.trace_id` attribute) — so you can search for one ID and find the complete request flow across your logs, error tracking, and distributed traces.
 
 See the [Tracing How-To](/howto/Tracing/#trace-id-propagation) for details.
 
diff --git a/config-reference.md b/config-reference.md
index fa21f30..ae63a6e 100644
--- a/config-reference.md
+++ b/config-reference.md
@@ -79,6 +79,8 @@ cfg := config.GetColdBrewConfig()
 | `JSON_BUILTIN_MARSHALLER_MIME` | string | `application/json` | Content-Type for the JSON builtin marshaller |
 | `HTTP_HEADER_PREFIXES` | []string | `""` | HTTP header prefixes to forward as gRPC metadata (comma-separated) |
 | `TRACE_HEADER_NAME` | string | `x-trace-id` | HTTP header name for trace ID propagation to log/trace contexts |
+| `DISABLE_HTTP_COMPRESSION` | bool | `false` | Disable gzip/zstd compression for HTTP gateway responses |
+| `HTTP_COMPRESSION_MIN_SIZE` | int | `256` | Minimum response body size (bytes) before compression is applied. Responses smaller than this are sent uncompressed |
 
 ## Prometheus Metrics
 
@@ -94,7 +96,7 @@ cfg := config.GetColdBrewConfig()
 |----------|------|---------|-------------|
 | `NEW_RELIC_LICENSE_KEY` | string | `""` | New Relic license key (required to enable New Relic) |
 | `NEW_RELIC_APPNAME` | string | `""` | Application name in New Relic |
-| `DISABLE_NEW_RELIC` | bool | `false` | Disable all New Relic reporting |
+| `DISABLE_NEW_RELIC` | bool | `false` | Disable all New Relic reporting. **Note:** automatically set to `true` at startup when `NEW_RELIC_LICENSE_KEY` is empty, so the effective default for services without a license key is `true` |
 | `NEW_RELIC_DISTRIBUTED_TRACING` | bool | `true` | Enable New Relic distributed tracing |
 | `NEW_RELIC_OPENTELEMETRY` | bool | `true` | Enable New Relic via OpenTelemetry |
 | `NEW_RELIC_OPENTELEMETRY_SAMPLE` | float64 | `0.2` | Trace sampling ratio for New Relic OpenTelemetry (0.0–1.0) |
@@ -127,6 +129,13 @@ When `OTLP_ENDPOINT` is set, it takes precedence over New Relic OpenTelemetry co
 | `SHUTDOWN_DURATION_IN_SECONDS` | int | `15` | Time to wait for in-flight requests to complete before forced shutdown |
 | `GRPC_GRACEFUL_DURATION_IN_SECONDS` | int | `7` | Time to wait for healthcheck failure to propagate before initiating shutdown. Should be less than `SHUTDOWN_DURATION_IN_SECONDS` |
 
+## Response Time Logging
+
+| Variable | Type | Default | Description |
+|----------|------|---------|-------------|
+| `RESPONSE_TIME_LOG_LEVEL` | string | `info` | Log level for per-request response time logging. Valid: `debug`, `info`, `warn`, `error`. Invalid values fall back to `info`. Must be >= `LOG_LEVEL` to take effect |
+| `RESPONSE_TIME_LOG_ERROR_ONLY` | bool | `false` | When `true`, only log response time for requests that return an error. Successful requests are not logged. Note: if `LOG_LEVEL` is set higher than `RESPONSE_TIME_LOG_LEVEL`, response time logs are already suppressed |
+
 ## Runtime
 
 | Variable | Type | Default | Description |
@@ -164,6 +173,21 @@ export OTLP_SAMPLING_RATIO=1.0
 export DISABLE_NEW_RELIC=true
 ```
 
+## Example: High-Throughput Production
+
+For services at 70k+ QPS where observability overhead matters:
+
+```bash
+export APP_NAME=myservice
+export ENVIRONMENT=production
+export LOG_LEVEL=warn                       # suppresses info-level response time logs
+# export OTLP_ENDPOINT=your-collector:4317  # uncomment if using OTLP tracing
+export OTLP_SAMPLING_RATIO=0.05              # only applies when OTLP_ENDPOINT is set
+export ENABLE_PROMETHEUS_GRPC_HISTOGRAM=false
+export DISABLE_NEW_RELIC=true
+export HTTP_COMPRESSION_MIN_SIZE=512
+```
+
 ---
 
 Source: [`core/config/config.go`](https://github.com/go-coldbrew/core/blob/main/config/config.go)