# Create metric reduction rules

URL: https://docs.hanzo.ai/docs/openapi/o11y/createmetricreductionrule

> Creates a volume-control rule for a metric and returns it with its id; a metric that already has a rule is refused.

`POST /v1/o11y/metric_reduction_rules`

> [O11y →](https://docs.hanzo.ai/docs/openapi/o11y) · [All API references →](https://docs.hanzo.ai/docs/openapi) · [Get started →](https://docs.hanzo.ai/docs/guides)

|               |                                                       |
| ------------- | ----------------------------------------------------- |
| **Address**   | `https://api.hanzo.ai/v1/o11y/metric_reduction_rules` |
| **Method**    | `POST`                                                |
| **Operation** | `CreateMetricReductionRule`                           |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`                |

Creates a volume-control rule for a metric and returns
it with its id; a metric that already has a rule is refused.

## Request

3 fields, body `application/json` (required).

| Field        | In   | Type      | Required | Description                                                          |
| ------------ | ---- | --------- | -------- | -------------------------------------------------------------------- |
| `labels`     | body | string\[] | yes      | Labels are the label names the rule matches.                         |
| `matchType`  | body | string    | yes      | MatchType is drop or keep: drop the named labels, or keep only them. |
| `metricName` | body | string    | yes      | MetricName is the metric the rule governs; one rule per metric.      |

## Response

| Status    | Body                      | Meaning           |
| --------- | ------------------------- | ----------------- |
| `201`     | o11y.O11yReductionRuleOut | created           |
| `202`     | Approval                  | held for approval |
| `default` | problem-details           | refused           |

`201` body — 16 fields.

| Field                  | In   | Type                   | Always | Description                                                            |
| ---------------------- | ---- | ---------------------- | ------ | ---------------------------------------------------------------------- |
| `data`                 | body | o11y.O11yReductionRule | —      |                                                                        |
| `data.active`          | body | boolean                | —      | Active says whether the rule is in force.                              |
| `data.createdAt`       | body | string (date-time)     | —      | CreatedAt is when the rule was created.                                |
| `data.createdBy`       | body | string                 | —      | CreatedBy is who created it.                                           |
| `data.effectiveFrom`   | body | string (date-time)     | —      | EffectiveFrom is when the rule took effect.                            |
| `data.id`              | body | string                 | —      | ID is the rule's id.                                                   |
| `data.ingestedSamples` | body | integer (uint64)       | —      | IngestedSamples is how many samples arrived while the rule was active. |
| `data.ingestedSeries`  | body | integer (uint64)       | —      | IngestedSeries is how many series arrived while the rule was active.   |
| `data.labels`          | body | string\[]              | —      | Labels are the label names the rule matches.                           |
| `data.matchType`       | body | string                 | —      | MatchType is drop or keep.                                             |
| `data.metricName`      | body | string                 | —      | MetricName is the metric the rule governs.                             |
| `data.retainedSamples` | body | integer (uint64)       | —      | RetainedSamples is how many of them were kept.                         |
| `data.retainedSeries`  | body | integer (uint64)       | —      | RetainedSeries is how many of them were kept.                          |
| `data.updatedAt`       | body | string (date-time)     | —      | UpdatedAt is when the rule last changed.                               |
| `data.updatedBy`       | body | string                 | —      | UpdatedBy is who last changed it.                                      |
| `status`               | body | string                 | —      | Status is "success".                                                   |

Failure carries the platform error shape — see [Errors](https://docs.hanzo.ai/docs/errors).

## Examples

**CLI**

```bash
hanzo o11y metric_reduction_rules create \
  --labels '["<labels>"]' \
  --match-type <matchType> \
  --metric-name <metricName>
```

**SDK**

**.ts**

```ts
import { Configuration, O11yApi } from 'hanzoai';

const api = new O11yApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.createMetricReductionRule({ metricName: "<metricName>", matchType: "<matchType>", labels: ["<labels>"] });
```

**.py**

```python
from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import O11yApi

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = O11yApi(client).create_metric_reduction_rule(metric_name="<metricName>", match_type="<matchType>", labels=["<labels>"])
```

**.go**

```go
cfg := hanzoai.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := hanzoai.NewAPIClient(cfg)

resp, _, err := client.O11yAPI.CreateMetricReductionRule(context.Background()).Execute()
if err != nil {
	return err
}
```

**.rs**

```rust
use hanzo_client::apis::{configuration::Configuration, o11y_api};

let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();

let result = o11y_api::create_metric_reduction_rule(&cfg, Default::default()).await?;
```

**.java**

```java
import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.O11yApi;

ApiClient client = new ApiClient();
client.setBearerToken(System.getenv("HANZO_API_KEY"));

var result = new O11yApi(client).createMetricReductionRule();
```

**HTTP**

```bash
curl -X POST https://api.hanzo.ai/v1/o11y/metric_reduction_rules \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "metricName": "<metricName>",
       "matchType": "<matchType>",
       "labels": [
         "<labels>"
       ]
     }'
```

**MCP**

Tool `o11y`, op `CreateMetricReductionRule` — POST the JSON-RPC envelope to `https://api.hanzo.ai/v1/mcp`.

```bash
curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "o11y",
         "arguments": {
           "op": "CreateMetricReductionRule",
           "input": {
             "metricName": "<metricName>",
             "matchType": "<matchType>",
             "labels": [
               "<labels>"
             ]
           }
         }
       }
     }'
```

---

[O11y API](https://docs.hanzo.ai/docs/openapi/o11y) · [All Hanzo APIs](https://docs.hanzo.ai/docs/openapi) · [Interactive reference](https://docs.hanzo.ai/docs/openapi/reference)