# Create messages — POST /v1/messages

URL: https://docs.hanzo.ai/docs/openapi/ai/post-messages

> Implements the Anthropic Messages API.

`POST /v1/messages`

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

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

Implements the Anthropic Messages API.

## Request

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

| Field                  | In   | Type                   | Required | Description |
| ---------------------- | ---- | ---------------------- | -------- | ----------- |
| `max_tokens`           | body | integer                | —        |             |
| `messages`             | body | ai.AnthropicMessage\[] | —        |             |
| `messages[].content`   | body | any                    | —        |             |
| `messages[].role`      | body | string                 | —        |             |
| `model`                | body | string                 | —        |             |
| `stream`               | body | boolean                | —        |             |
| `system`               | body | any                    | —        |             |
| `temperature`          | body | number                 | —        |             |
| `thinking`             | body | any                    | —        |             |
| `tool_choice`          | body | any                    | —        |             |
| `tools`                | body | ai.AnthropicTool\[]    | —        |             |
| `tools[].description`  | body | string                 | —        |             |
| `tools[].input_schema` | body | any                    | —        |             |
| `tools[].name`         | body | string                 | —        |             |

## Response

| Status | Body                 | Meaning                                             |
| ------ | -------------------- | --------------------------------------------------- |
| `200`  | ai.AnthropicResponse | Success.                                            |
| `401`  | —                    | No credential, or one this service does not accept. |
| `403`  | —                    | A valid credential that may not do this.            |

`200` body — 17 fields.

| Field                                            | In   | Type                        | Always | Description |
| ------------------------------------------------ | ---- | --------------------------- | ------ | ----------- |
| `content`                                        | body | ai.AnthropicContentBlock\[] | —      |             |
| `content[].text`                                 | body | string                      | —      |             |
| `content[].type`                                 | body | string                      | —      |             |
| `id`                                             | body | string                      | —      |             |
| `model`                                          | body | string                      | —      |             |
| `role`                                           | body | string                      | —      |             |
| `stop_reason`                                    | body | string                      | —      |             |
| `type`                                           | body | string                      | —      |             |
| `usage`                                          | body | ai.AnthropicUsage           | —      |             |
| `usage.cache_creation`                           | body | ai.CacheWrites              | —      |             |
| `usage.cache_creation.ephemeral_1h_input_tokens` | body | integer                     | —      |             |
| `usage.cache_creation.ephemeral_5m_input_tokens` | body | integer                     | —      |             |
| `usage.cache_creation_input_tokens`              | body | integer                     | —      |             |
| `usage.cache_read_input_tokens`                  | body | integer                     | —      |             |
| `usage.input_tokens`                             | body | integer                     | —      |             |
| `usage.iterations`                               | body | ai.AnthropicUsage\[]        | —      |             |
| `usage.output_tokens`                            | body | integer                     | —      |             |

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

## Examples

**CLI**

```bash
hanzo messages create
```

**SDK**

**.ts**

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

const api = new AiApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postMessages({ max_tokens: 0, messages: [{"content":"<content>","role":"<role>"}] });
```

**.py**

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

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = AiApi(client).post_messages(max_tokens=0, messages=[{"content":"<content>","role":"<role>"}])
```

**.go**

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

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

**.rs**

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

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

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

**.java**

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

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

var result = new AiApi(client).postMessages();
```

**HTTP**

```bash
curl -X POST https://api.hanzo.ai/v1/messages \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "max_tokens": 0,
       "messages": [
         {
           "content": "<content>",
           "role": "<role>"
         }
       ]
     }'
```

**MCP**

MCP declares no tool for **ai** — `tools/list` on `https://api.hanzo.ai/v1/mcp` names the products it does reach. Use HTTP or an SDK.

---

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