> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.cessy.ai/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.cessy.ai/_mcp/server.

# List channel messages

GET https://cessy.ai/api/rest/tenant-id/app-id/channels/{channelId}/messages

Reference: https://docs.cessy.ai/runtime-api-template/channels/list-channel-messages

## Authentication

- `Authorization` header (bearer token, required) — OAuth/JWT bearer with the 'runtime' scope that resolves to a user principal. API keys and agent service tokens are rejected by user-delegated operations.

## Request

### Path parameters

- `channelId` (string, required) — Channel id.

### Query parameters

- `agentId` (string, optional) — Optional agent participant id filter within this app.
- `limit` (integer, optional, default: 50) — Maximum number of messages to return.
- `before` (string, optional) — Exclusive message id cursor for backward pagination.
- `workspaceId` (string, optional) — Optional Workspace runtime selector for preview or validation calls. If supplied with X-CES-Workspace-ID, both values must match.

### Headers

- `X-CES-Workspace-ID` (string, optional) — Optional Workspace runtime selector header. If supplied with workspaceId, both values must match.

## Response

### 200

Channel message page

- `messages` (list of map from string to any, required)
- `hasMore` (boolean, required)
- `expired` (boolean, optional) — True when the before cursor was too old to serve precisely.

## Errors

### 400 Bad Request Error

Invalid query parameter

- `error` (string, required)
- `message` (string, optional) — Operator-safe failure text when the endpoint exposes a typed error.
- `details` (any, optional)
- `code` (string, optional) — Stable machine-readable failure category when available.
- `executionId` (string, optional) — Protected execution-log lookup identifier when execution started.
- `correlationId` (string, optional) — Identifier for related requests and diagnostics when available.
- `effectState` (enum, optional) — Authoritative confirmation that the command effect is absent.
  - Allowed values: `rejected`, `rolled_back`

### 401 Unauthorized Error

Missing or invalid user bearer token

- `error` (string, required)
- `message` (string, optional) — Operator-safe failure text when the endpoint exposes a typed error.
- `details` (any, optional)
- `code` (string, optional) — Stable machine-readable failure category when available.
- `executionId` (string, optional) — Protected execution-log lookup identifier when execution started.
- `correlationId` (string, optional) — Identifier for related requests and diagnostics when available.
- `effectState` (enum, optional) — Authoritative confirmation that the command effect is absent.
  - Allowed values: `rejected`, `rolled_back`

### 403 Forbidden Error

The user cannot read this channel

- `error` (string, required)
- `message` (string, optional) — Operator-safe failure text when the endpoint exposes a typed error.
- `details` (any, optional)
- `code` (string, optional) — Stable machine-readable failure category when available.
- `executionId` (string, optional) — Protected execution-log lookup identifier when execution started.
- `correlationId` (string, optional) — Identifier for related requests and diagnostics when available.
- `effectState` (enum, optional) — Authoritative confirmation that the command effect is absent.
  - Allowed values: `rejected`, `rolled_back`

### 404 Not Found Error

Channel not found

- `error` (string, required)
- `message` (string, optional) — Operator-safe failure text when the endpoint exposes a typed error.
- `details` (any, optional)
- `code` (string, optional) — Stable machine-readable failure category when available.
- `executionId` (string, optional) — Protected execution-log lookup identifier when execution started.
- `correlationId` (string, optional) — Identifier for related requests and diagnostics when available.
- `effectState` (enum, optional) — Authoritative confirmation that the command effect is absent.
  - Allowed values: `rejected`, `rolled_back`

## Examples

**Request**

```json
{}
```

**Response**

```json
{
  "messages": [
    {}
  ],
  "hasMore": false,
  "expired": false
}
```

**SDK Code**

```python
import requests

url = "https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages"

payload = {}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.get(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages';
const options = {
  method: 'GET',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages"

	payload := strings.NewReader("{}")

	req, _ := http.NewRequest("GET", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.get("https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('GET', 'https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages', [
  'body' => '{}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages");
var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://cessy.ai/api/rest/tenant-id/app-id/channels/channelId/messages")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```