# List sessions — GET /v1/o11y/sessions

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

> Answers the caller org's LLM-observability sessions — traces grouped by session id on the gen_ai span plane — paged by limit and offset, in the runtime's own envelope, passed through unchanged.

`GET /v1/o11y/sessions`

> [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/sessions` |
| **Method**    | `GET`                                   |
| **Operation** | `get_o11y_sessions`                     |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`  |

Answers the caller org's LLM-observability sessions — traces grouped by session id on the gen\_ai span plane — paged by limit and offset, in the runtime's own envelope, passed through unchanged.

An org-less caller is refused HERE, at the cloud boundary, before the request reaches the runtime, and the org the runtime then scopes on is that SAME validated tenant. The two cannot disagree: the tenant is minted from the principal's own claim at ingress and a client copy never survives it.

There is deliberately no session-detail route to pair with this. The runtime serves the list only; detail is composed client-side from this list plus the traces filtered by session, so a caller looking for one is looking for something that was never served rather than something that broke.

## Request

`GET /v1/o11y/sessions` takes no parameters and no body — the credential is the whole request.

## Response

The document declares no response body for this operation. It answers `200` on success and the platform error shape on failure — see [Errors](https://docs.hanzo.ai/docs/errors).

## Examples

**CLI**

```bash
hanzo o11y sessions
```

**SDK**

**.ts**

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

const api = new O11yApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.getO11ySessions();
```

**.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_sessions()
```

**.go**

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

resp, _, err := client.O11yAPI.GetO11ySessions(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_sessions(&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).getO11ySessions();
```

**HTTP**

```bash
curl https://api.hanzo.ai/v1/o11y/sessions \
  -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)