# Send channel

URL: https://docs.hanzo.ai/docs/openapi/channel/post-channel-by-channel-send

> Delivers text, attachments and actions to one room on a connected chat transport — discord, github, linear, slack, teams, telegram or whatsapp — and answers that transport's own receipt, the `messageId` it assigned and the Unix second it landed.

`POST /v1/channel/{channel}/send`

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

|               |                                                  |
| ------------- | ------------------------------------------------ |
| **Address**   | `https://api.hanzo.ai/v1/channel/{channel}/send` |
| **Method**    | `POST`                                           |
| **Operation** | `post_channel_by_channel_send`                   |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`           |

Delivers text, attachments and actions to one room on a connected chat transport — discord, github, linear, slack, teams, telegram or whatsapp — and answers that transport's own receipt, the `messageId` it assigned and the Unix second it landed. An unknown channel is a 404.

The body is the envelope's NARROW outbound projection: `room`, `text`, `attachments`, `actions`, `replyTo` and `idempotency`, and nothing else. Identity is not a field — the channel is the path segment and the sender is the caller's validated org — so a body carrying `sender`, `account` or `channel` is refused with 400 rather than having it silently dropped. `room.id` is required, and so is something to say: text, or at least one attachment.

Requires a validated principal; 401 without one. The room must already belong to the caller's org — each transport verifies the binding itself, so a room this org has not bound is 403 and a room whose route the bot has never learned is 409, meaning someone has to message the bot there first. A route learned only so a pairing reply could be delivered lasts exactly as long as that pairing request does, so a room whose sender was never approved goes back to 409 within the hour. A transport that fails answers 502 carrying status and shape only, never a token.

Sending is at-most-once only if you ask for it: pass an `idempotency` string and a replay answers 200 with the PRIOR receipt instead of sending twice, while a send that fails releases the key so the caller can re-attempt. Bodies over 1 MiB are refused. Every transport currently renders text only, so attachments and actions are flattened deterministically to one line each after the text rather than dropped.

## Request

1 field.

| Field     | In   | Type   | Required | Description |
| --------- | ---- | ------ | -------- | ----------- |
| `channel` | path | string | yes      |             |

## 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 channel send <channel>
```

**SDK**

**.ts**

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

const api = new ChannelApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postChannelByChannelSend({ channel: 'channel' });
```

**.py**

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

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = ChannelApi(client).post_channel_by_channel_send(channel='channel')
```

**.go**

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

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

**.rs**

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

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

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

**.java**

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

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

var result = new ChannelApi(client).postChannelByChannelSend();
```

**HTTP**

```bash
curl -X POST https://api.hanzo.ai/v1/channel/<channel>/send \
  -H "Authorization: Bearer $HANZO_API_KEY"
```

**MCP**

MCP reaches **channel** through the `channel` tool, which names its 8 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_channels"
         }
       }
     }'
```

---

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