# Replace kv

URL: https://docs.hanzo.ai/docs/openapi/kv/put-kv-by-bucket-by-key

> Sets one key to one value and returns the revision the write created.

`PUT /v1/kv/{bucket}/{key}`

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

|               |                                             |
| ------------- | ------------------------------------------- |
| **Address**   | `https://api.hanzo.ai/v1/kv/{bucket}/{key}` |
| **Method**    | `PUT`                                       |
| **Operation** | `put_kv_by_bucket_by_key`                   |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`      |

Sets one key to one value and returns the revision the write created.
Writes are versioned: each put is a new revision and the bucket retains up to
its History of them per key.

## Request

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

| Field    | In   | Type   | Required | Description                                                          |
| -------- | ---- | ------ | -------- | -------------------------------------------------------------------- |
| `bucket` | path | string | yes      | Bucket is the bucket, from the path.                                 |
| `key`    | path | string | yes      | Key is the key, from the path.                                       |
| `bucket` | body | string | —        | Bucket is the bucket, from the path.                                 |
| `key`    | body | string | —        | Key is the key, from the path.                                       |
| `value`  | body | string | —        | Value is the value, carried verbatim as UTF-8 text (typically JSON). |

## Response

| Status    | Body            | Meaning |
| --------- | --------------- | ------- |
| `200`     | kv.kvAck        | ok      |
| `default` | problem-details | refused |

`200` body — 1 field.

| Field      | In   | Type             | Always | Description                                 |
| ---------- | ---- | ---------------- | ------ | ------------------------------------------- |
| `revision` | body | integer (uint64) | —      | Revision is the revision the write created. |

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

## Examples

**CLI**

```bash
hanzo kv bucket set <bucket> <key>
```

**SDK**

**.ts**

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

const api = new KvApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.putKvByBucketByKey({ bucket: 'bucket', key: 'key', bucket: "<bucket>", key: "<key>" });
```

**.py**

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

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = KvApi(client).put_kv_by_bucket_by_key(bucket='bucket', key='key', bucket="<bucket>", key="<key>")
```

**.go**

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

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

**.rs**

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

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

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

**.java**

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

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

var result = new KvApi(client).putKvByBucketByKey();
```

**HTTP**

```bash
curl -X PUT https://api.hanzo.ai/v1/kv/<bucket>/<key> \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "bucket": "<bucket>",
       "key": "<key>"
     }'
```

**MCP**

MCP reaches **kv** through the `kv` tool, which names its 6 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": "get_kv"
         }
       }
     }'
```

---

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