For the complete documentation index, see llms.txt. Markdown versions of all docs pages are available by appending .md to any docs URL.
Metrics reference
Review the metrics that are available in agentgateway.
Note
All counter and histogram metrics only appear in the output after the first request of that type. For example, agentgateway_mcp_requests_total is not present until MCP traffic is received. This is normal Prometheus behavior. Counters and histograms are not pre-initialized.
XDS
These metrics track communication with an XDS management server. They are registered only when agentgateway runs in Kubernetes mode against a control plane, and do not appear on the metrics endpoint of a standalone process.
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_xds_connection_terminations_total | Counter | — | The total number of completed connections to xds server (unstable). |
agentgateway_xds_message_bytes_total | Counter | bytes | Total number of bytes received (unstable). |
agentgateway_xds_message_total | Counter | — | Total number of messages received (unstable). |
HTTP
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_request_duration_seconds | Histogram | seconds | Duration of HTTP requests (seconds). |
agentgateway_request_processing_seconds | Histogram | seconds | Duration from receiving an HTTP request to sending the primary outbound call (seconds). |
agentgateway_requests_total | Counter | — | The total number of HTTP requests sent. |
agentgateway_response_bytes_total | Counter | bytes | Total HTTP response bytes received. |
agentgateway_response_processing_seconds | Histogram | seconds | Duration from receiving the primary outbound response to sending the HTTP response (seconds). |
agentgateway_retries_total | Counter | — | The total number of request retries. |
TCP
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_downstream_connections_total | Counter | — | The total number of downstream connections established. |
agentgateway_downstream_received_bytes_total | Counter | bytes | Total TCP bytes received per connection labels. |
agentgateway_downstream_sent_bytes_total | Counter | bytes | Total TCP bytes transmitted per connection labels. |
agentgateway_tls_handshake_duration_seconds | Histogram | seconds | Duration to complete inbound TLS/HTTPS handshake (seconds). |
agentgateway_upstream_connect_duration_seconds | Histogram | seconds | Duration to establish upstream connection (seconds). |
MCP
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_mcp_requests_total | Counter | — | Total number of MCP requests. |
LLM
These metrics follow the OpenTelemetry semantic conventions for generative AI.
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_cost_catalog_lookups_total | Counter | — | Total number of model cost catalog lookups by resolution status. |
agentgateway_gen_ai_client_cost_usd_total | Counter | usd | Cumulative USD cost of generative AI requests. |
agentgateway_gen_ai_client_token_usage | Histogram | — | Number of tokens used per request. |
agentgateway_gen_ai_server_request_duration | Histogram | — | Duration of generative AI request. |
agentgateway_gen_ai_server_time_per_output_token | Histogram | — | Time to generate each output token for a given request. |
agentgateway_gen_ai_server_time_to_first_token | Histogram | — | Time to generate the first token for a given request. |
agentgateway_guardrail_checks_total | Counter | — | Total number of guardrail checks. |
Misc
The following metrics reflect the health of the agentgateway process itself and appear on every startup, regardless of traffic.
| Metric | Type | Unit | Description |
|---|---|---|---|
agentgateway_build_info | Info | — | Agentgateway build information. |
agentgateway_config_synchronized | Gauge | — | Whether the last configuration load/reload was successful or not, being synchronized with the on-disk configuration. |
agentgateway_upstream_call_duration_seconds | Histogram | seconds | Duration of outbound calls made by agentgateway (seconds). |
agentgateway_tokio_num_workers | Gauge | — | The number of worker threads that the async runtime uses. |
agentgateway_tokio_num_alive_tasks | Gauge | — | The number of tasks that are currently alive in the async runtime. |
agentgateway_tokio_global_queue_depth | Gauge | — | The number of tasks that are currently scheduled in the async runtime’s global queue. |
