Create Session

curl --request POST \
  --url https://api.example.com/api/sessions \
  --header 'Content-Type: application/json' \
  --data '
{
  "organizationId": "<string>",
  "initialMessage": "<string>",
  "repoUrl": "<string>",
  "baseBranch": "<string>",
  "model": "<string>"
}
'

import requests

url = "https://api.example.com/api/sessions"

payload = {
    "organizationId": "<string>",
    "initialMessage": "<string>",
    "repoUrl": "<string>",
    "baseBranch": "<string>",
    "model": "<string>"
}
headers = {"Content-Type": "application/json"}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    organizationId: '<string>',
    initialMessage: '<string>',
    repoUrl: '<string>',
    baseBranch: '<string>',
    model: '<string>'
  })
};

fetch('https://api.example.com/api/sessions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/api/sessions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'organizationId' => '<string>',
    'initialMessage' => '<string>',
    'repoUrl' => '<string>',
    'baseBranch' => '<string>',
    'model' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.example.com/api/sessions"

	payload := strings.NewReader("{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}")

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

	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.example.com/api/sessions")
  .header("Content-Type", "application/json")
  .body("{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.example.com/api/sessions")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}"

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

{
  "session": {}
}

POST

api

sessions

Create Session

curl --request POST \
  --url https://api.example.com/api/sessions \
  --header 'Content-Type: application/json' \
  --data '
{
  "organizationId": "<string>",
  "initialMessage": "<string>",
  "repoUrl": "<string>",
  "baseBranch": "<string>",
  "model": "<string>"
}
'

import requests

url = "https://api.example.com/api/sessions"

payload = {
    "organizationId": "<string>",
    "initialMessage": "<string>",
    "repoUrl": "<string>",
    "baseBranch": "<string>",
    "model": "<string>"
}
headers = {"Content-Type": "application/json"}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    organizationId: '<string>',
    initialMessage: '<string>',
    repoUrl: '<string>',
    baseBranch: '<string>',
    model: '<string>'
  })
};

fetch('https://api.example.com/api/sessions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/api/sessions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'organizationId' => '<string>',
    'initialMessage' => '<string>',
    'repoUrl' => '<string>',
    'baseBranch' => '<string>',
    'model' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.example.com/api/sessions"

	payload := strings.NewReader("{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}")

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

	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.example.com/api/sessions")
  .header("Content-Type", "application/json")
  .body("{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.example.com/api/sessions")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"organizationId\": \"<string>\",\n  \"initialMessage\": \"<string>\",\n  \"repoUrl\": \"<string>\",\n  \"baseBranch\": \"<string>\",\n  \"model\": \"<string>\"\n}"

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

{
  "session": {}
}

Authentication

Requires browser authentication (dashboard). API keys cannot create sessions — sessions must be attributed to a specific user.

Request body

string

required

The ID of the workspace to create the session in.

string

The initial prompt for the agent. A title is auto-generated from this message.

string

GitHub repository URL to clone (e.g., https://github.com/owner/repo). The sandbox will clone this repo before the agent starts working.

string

The branch to base changes on. Defaults to main. Only used when repoUrl is provided.

string

The Claude model to use. Defaults to claude-opus-4-6.

Response

Returns 201 Created with the newly created session.

object

The created session object. See List Sessions for the full schema.

Example

This endpoint requires browser authentication (session cookie). The example below shows the request shape — to create sessions, use the Magnet dashboard or the API from an authenticated browser context.

cURL

curl -X POST "https://magnet.run/api/sessions" \
  -H "Content-Type: application/json" \
  -H "Cookie: __session=<your-session-token>" \
  -d '{
    "organizationId": "org_abc123",
    "initialMessage": "Add input validation to the signup form. Email should be validated, password needs 8+ chars with at least one number.",
    "repoUrl": "https://github.com/acme/web-app",
    "baseBranch": "main"
  }'

Response

{
  "session": {
    "id": "cm3abc123def",
    "title": "Add input validation to signup form",
    "status": "active",
    "createdAt": "2026-02-11T10:00:00.000Z",
    "updatedAt": "2026-02-11T10:00:00.000Z",
    "model": "claude-opus-4-6",
    "author": {
      "id": "user_123",
      "name": "Alice Chen"
    },
    "metadata": {
      "repository": "acme/web-app"
    },
    "messageCount": 1,
    "firstMessagePreview": "Add input validation to the signup form..."
  }
}

Errors

Status	Description
`400`	Invalid request body or API key used instead of browser session
`401`	Invalid or missing authentication
`403`	No access to the specified workspace
`500`	Server error

Session creation requires browser authentication. If you need to create sessions programmatically, use the Magnet dashboard.

​Authentication

​Request body

​Response

​Example

​Response

​Errors

Authentication

Request body

Response

Example

Response

Errors