# List keys — GET /v1/o11y/fields/keys

URL: https://docs.hanzo.ai/docs/openapi/o11y/get-o11y-fields-keys

> Returns the telemetry field keys matching the selector — the signal's fields grouped by name, and whether the catalog is complete.

`GET /v1/o11y/fields/keys`

> [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/fields/keys` |
| **Method**    | `GET`                                      |
| **Operation** | `get_o11y_fields_keys`                     |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`     |

Returns the telemetry field keys matching the selector — the
signal's fields grouped by name, and whether the catalog is complete.

Callers need the viewer role; the runtime's own gate enforces it.

## Request

10 fields.

| Field             | In    | Type    | Required | Description                                                                                     |
| ----------------- | ----- | ------- | -------- | ----------------------------------------------------------------------------------------------- |
| `signal`          | query | string  | —        | Signal is the telemetry to read the fields of — traces, logs or metrics.                        |
| `source`          | query | string  | —        | Source narrows the fields to one source within the signal.                                      |
| `limit`           | query | integer | —        | Limit caps how many keys come back.                                                             |
| `startUnixMilli`  | query | integer | —        | StartUnixMilli is the window start as a unix millisecond epoch.                                 |
| `endUnixMilli`    | query | integer | —        | EndUnixMilli is the window end as a unix millisecond epoch.                                     |
| `fieldContext`    | query | string  | —        | FieldContext narrows the keys to one context — resource, scope, attribute, span, log or metric. |
| `fieldDataType`   | query | string  | —        | FieldDataType narrows the keys to one data type.                                                |
| `metricName`      | query | string  | —        | MetricName narrows the keys to those on one metric.                                             |
| `metricNamespace` | query | string  | —        | MetricNamespace narrows the keys to one metric namespace.                                       |
| `searchText`      | query | string  | —        | SearchText narrows the keys to those containing it.                                             |

## Response

| Status    | Body                  | Meaning           |
| --------- | --------------------- | ----------------- |
| `200`     | o11y.O11yFieldKeysOut | ok                |
| `202`     | Approval              | held for approval |
| `default` | problem-details       | refused           |

`200` body — 11 fields.

| Field                         | In   | Type                      | Always | Description          |
| ----------------------------- | ---- | ------------------------- | ------ | -------------------- |
| `data`                        | body | o11y.GettableFieldKeys    | —      |                      |
| `data.complete`               | body | boolean                   | —      |                      |
| `data.keys`                   | body | object                    | —      |                      |
| `data.keys.*`                 | body | o11y.TelemetryFieldKey\[] | —      |                      |
| `data.keys.*[].description`   | body | string                    | —      |                      |
| `data.keys.*[].fieldContext`  | body | any                       | —      |                      |
| `data.keys.*[].fieldDataType` | body | any                       | —      |                      |
| `data.keys.*[].name`          | body | string                    | yes    |                      |
| `data.keys.*[].signal`        | body | any                       | —      |                      |
| `data.keys.*[].unit`          | body | string                    | —      |                      |
| `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 fields keys
```

**SDK**

**.ts**

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

const api = new O11yApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.getO11yFieldsKeys();
```

**.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).get_o11y_fields_keys()
```

**.go**

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

resp, _, err := client.O11yAPI.GetO11yFieldsKeys(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::get_o11y_fields_keys(&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).getO11yFieldsKeys();
```

**HTTP**

```bash
curl https://api.hanzo.ai/v1/o11y/fields/keys \
  -H "Authorization: Bearer $HANZO_API_KEY"
```

**MCP**

MCP reaches **o11y** through the `o11y` tool, which names its 307 operations with its own verbs — this one among them, under a name only MCP declares. `describe` explains any of them:

```bash
curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "describe",
         "arguments": {
           "op": "list_o11y_autocomplete_aggregate_attributes"
         }
       }
     }'
```

---

[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)