anthropic-proxy/docs/metrics.md

Metrics Reference

All metrics are emitted via OpenTelemetry (OTLP gRPC) with cumulative temporality. OTel metric names use dots; Prometheus converts them to underscores and appends _total for counters.

Counters

OTel Name	Prometheus Name	Attributes	Description
proxy.request.count	proxy_request_count_total	model, stream, status_code	Total proxied requests
proxy.tokens.input	proxy_tokens_input_total	model, credential	Input tokens consumed
proxy.tokens.output	proxy_tokens_output_total	model, credential	Output tokens consumed
proxy.upstream.errors	proxy_upstream_errors_total	error_type, credential, status_code	Upstream errors (connection failures, 4xx/5xx)
proxy.credential.cooldowns	proxy_credential_cooldowns_total	status_code	Credential cooldown activations (rate limited)
proxy.stream.requests	proxy_stream_requests_total	model	Streaming request count

Histograms

OTel Name	Prometheus Name	Unit	Attributes	Description
proxy.request.duration_ms	proxy_request_duration_ms_milliseconds	ms	model, stream, status_code	Request latency
proxy.request.body_size_bytes	proxy_request_body_size_bytes	bytes	model, stream	Request body size

Gauges

OTel Name	Prometheus Name	Attributes	Description
proxy.usage.utilization	proxy_usage_utilization	window	Current utilization % from Anthropic API (0-100)
proxy.usage.resets_at	proxy_usage_resets_at	window	Unix timestamp when the rate limit window resets
proxy.credential.active	proxy_credential_active	—	Currently active (non-cooldown) credentials

Window attribute values

• 5h — 5-hour rolling window
• 7d — 7-day rolling window
• 7d_sonnet — 7-day Sonnet-specific window

Structured Logs (Loki)

Each completed request emits a structured log line via OTel LogBridge. Fields are stored as Loki stream labels/structured metadata.

Field	Type	Description
input_tokens	int	Input tokens for this request
output_tokens	int	Output tokens for this request
model	string	Model used
latency_ms	float	Request latency in milliseconds
status	int	HTTP status code (non-stream only)
stream	bool	Whether this was a streaming request

Log messages: "request completed" (non-stream), "stream completed" (stream).

Per-window token counting via Loki

Window token totals are computed in Grafana using LogQL, not tracked in-memory. This approach survives process restarts and uses exact Anthropic window boundaries.

Grafana variables derive the window age from Prometheus:

window_age_5h = time() - proxy_usage_resets_at{window="5h"} + 18000
window_age_7d = time() - proxy_usage_resets_at{window="7d"} + 604800

LogQL queries sum token values from individual log events within the window:

sum(sum_over_time(
  {service_name="anthropic-proxy"} |= "completed"
    | unwrap output_tokens
    | __error__=""
  [${window_age_5h}s]
))

Annotations (Loki)

429 rate limit events are surfaced as Grafana annotations:

{service_name="anthropic-proxy"} |= "upstream error" | json | status = "429"