> ## Documentation Index
> Fetch the complete documentation index at: https://www.truefoundry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AI Gateway Metrics Rename — v0.136

> Metric names in AI Gateway are being renamed. A dual-write transition period lets you migrate dashboards and alerts without downtime.

<Warning>
  **Applicable to:** Users who have dashboards, alerts, or any monitoring pipelines that consume AI Gateway metrics with the `llm_gateway_*` prefix.
</Warning>

## What Is Changing

All metric names in AI Gateway are being renamed from the `llm_gateway_*` prefix to `ai_gateway_*`.

The general rule is a prefix swap: `llm_gateway_` → `ai_gateway_`. Two metrics differ from this rule: `llm_gateway_request_total_cost_total` → `ai_gateway_request_cost_total`, and `llm_gateway_agent_request_tool_calls_total` → `ai_gateway_agent_request_tool_calls`.

**Complete rename map (names as seen in Prometheus scrape):**

**Core request metrics**

| Old Name                                            | New Name                                           |
| --------------------------------------------------- | -------------------------------------------------- |
| `llm_gateway_requests_total`                        | `ai_gateway_requests_total`                        |
| `llm_gateway_input_tokens_total`                    | `ai_gateway_input_tokens_total`                    |
| `llm_gateway_output_tokens_total`                   | `ai_gateway_output_tokens_total`                   |
| `llm_gateway_request_total_cost_total`              | `ai_gateway_request_cost_total`                    |
| `llm_gateway_request_model_inference_failure_total` | `ai_gateway_request_model_inference_failure_total` |
| `llm_gateway_config_parsing_failures_total`         | `ai_gateway_config_parsing_failures_total`         |
| `llm_gateway_request_processing_ms`                 | `ai_gateway_request_processing_ms`                 |
| `llm_gateway_first_token_latency_ms`                | `ai_gateway_first_token_latency_ms`                |
| `llm_gateway_inter_token_latency_ms`                | `ai_gateway_inter_token_latency_ms`                |

**Agent metrics**

| Old Name                                                  | New Name                                                 |
| --------------------------------------------------------- | -------------------------------------------------------- |
| `llm_gateway_agent_requests_total`                        | `ai_gateway_agent_requests_total`                        |
| `llm_gateway_agent_request_duration_ms`                   | `ai_gateway_agent_request_duration_ms`                   |
| `llm_gateway_agent_request_tool_calls_total`              | `ai_gateway_agent_request_tool_calls`                    |
| `llm_gateway_agent_request_iteration_limit_reached_total` | `ai_gateway_agent_request_iteration_limit_reached_total` |
| `llm_gateway_agent_llm_latency_ms`                        | `ai_gateway_agent_llm_latency_ms`                        |
| `llm_gateway_agent_tool_calls_total`                      | `ai_gateway_agent_tool_calls_total`                      |
| `llm_gateway_agent_tool_latency_ms`                       | `ai_gateway_agent_tool_latency_ms`                       |
| `llm_gateway_agent_mcp_connect_latency_ms`                | `ai_gateway_agent_mcp_connect_latency_ms`                |

**Rate limit & routing metrics**

| Old Name                                               | New Name                                              |
| ------------------------------------------------------ | ----------------------------------------------------- |
| `llm_gateway_load_balanced_requests_total`             | `ai_gateway_load_balanced_requests_total`             |
| `llm_gateway_fallback_requests_total`                  | `ai_gateway_fallback_requests_total`                  |
| `llm_gateway_rate_limit_applied_total`                 | `ai_gateway_rate_limit_applied_total`                 |
| `llm_gateway_rate_limit_nominated_total`               | `ai_gateway_rate_limit_nominated_total`               |
| `llm_gateway_rate_limit_requests_total` *(deprecated)* | `ai_gateway_rate_limit_requests_total` *(deprecated)* |

**Budget metrics**

| Old Name                                           | New Name                                          |
| -------------------------------------------------- | ------------------------------------------------- |
| `llm_gateway_budget_applied_total`                 | `ai_gateway_budget_applied_total`                 |
| `llm_gateway_budget_nominated_total`               | `ai_gateway_budget_nominated_total`               |
| `llm_gateway_budget_requests_total` *(deprecated)* | `ai_gateway_budget_requests_total` *(deprecated)* |

**Guardrail metrics**

| Old Name                                     | New Name                                    |
| -------------------------------------------- | ------------------------------------------- |
| `llm_gateway_guardrails_requests_total`      | `ai_gateway_guardrails_requests_total`      |
| `llm_gateway_guardrail_requests_total`       | `ai_gateway_guardrail_requests_total`       |
| `llm_gateway_guardrail_execution_latency_ms` | `ai_gateway_guardrail_execution_latency_ms` |

**Model health metrics**

| Old Name                                             | New Name                                            |
| ---------------------------------------------------- | --------------------------------------------------- |
| `llm_gateway_model_cooldown_state_total`             | `ai_gateway_model_cooldown_state_total`             |
| `llm_gateway_model_threshold_latency_exceeded_total` | `ai_gateway_model_threshold_latency_exceeded_total` |

## Why This Change

The product has been rebranded from **LLM Gateway** to **AI Gateway** to reflect the broader set of capabilities it now supports (agents, MCP, guardrails, etc.). Aligning the OTel metric names with the product name makes monitoring consistent with the rest of the platform.

## Transition: Dual-Write Mode

To avoid breaking existing dashboards and alerts immediately, a **dual-write mode** was introduced in **v0.136.0**. When enabled, the `/metrics` endpoint emits **both** the old `llm_gateway_*` metrics and the new `ai_gateway_*` metrics in a single scrape response.

Dual-write is controlled by the environment variable:

```
ENABLE_DOUBLE_WRITE_FOR_METRICS=true   # default: true (since v0.136.0)
```

During the transition period, both sets of metrics are available simultaneously so you can update your dashboards at your own pace.

<Warning>
  The old `llm_gateway_*` metrics will no longer be published after **30th June 2026**. Ensure your dashboards and alerts are migrated to the new `ai_gateway_*` names before this date.
</Warning>

## What You Need to Do

<Steps>
  <Step title="Verify dual-write is active">
    Confirm that `ENABLE_DOUBLE_WRITE_FOR_METRICS` is set to `true` (it is `true` by default). Scrape the `/metrics` endpoint and verify you see both `llm_gateway_*` and `ai_gateway_*` series.
  </Step>

  <Step title="Update dashboards and alerts">
    Replace all references to `llm_gateway_*` OTel metric names with the corresponding `ai_gateway_*` names in your Grafana dashboards, Prometheus alerting rules, and any other monitoring configuration.

    Use the rename table above as your migration reference. The general pattern is:

    * Prefix: `llm_gateway_` → `ai_gateway_` (only change visible in the scraped output — counters retain `_total` as the Prometheus exporter re-adds it)
  </Step>

  <Step title="Disable dual-write after migration">
    Once all dashboards and alerts have been updated to use the new `ai_gateway_*` names, set `ENABLE_DOUBLE_WRITE_FOR_METRICS=false` to stop emitting the legacy metrics and reduce scrape payload size.
  </Step>
</Steps>

***

If you have questions or need help with the migration, reach out to [**support@truefoundry.com**](mailto:support@truefoundry.com) — we're happy to assist.