Fork a session

Fork a session

curl --request POST \
  --url https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "message": "Try the other approach"
}
'

import requests

url = "https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork"

payload = { "message": "Try the other approach" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({message: 'Try the other approach'})
};

fetch('https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork', 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.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork",
  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([
    'message' => 'Try the other approach'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork"

	payload := strings.NewReader("{\n  \"message\": \"Try the other approach\"\n}")

	req, _ := http.NewRequest("POST", 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(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"message\": \"Try the other approach\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"message\": \"Try the other approach\"\n}"

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

{
  "ok": true,
  "session_id": "0f8fad5b-d9cb-469f-a165-70867728950e"
}

{
  "error": "prompt_required"
}

{
  "error": "missing_bearer",
  "message": "Authorization required"
}

{
  "error": "missing_scope",
  "required_scope": "sessions:read"
}

{
  "error": "session_not_found"
}

{
  "error": {
    "type": "rate_limited",
    "message": "This API key exceeded its request-rate limit"
  }
}

POST

organizations

{orgId}

sessions

{sessionId}

fork

Fork a session

curl --request POST \
  --url https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "message": "Try the other approach"
}
'

import requests

url = "https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork"

payload = { "message": "Try the other approach" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({message: 'Try the other approach'})
};

fetch('https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork', 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.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork",
  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([
    'message' => 'Try the other approach'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork"

	payload := strings.NewReader("{\n  \"message\": \"Try the other approach\"\n}")

	req, _ := http.NewRequest("POST", 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(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"message\": \"Try the other approach\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.reasonmachines.com/v3/organizations/{orgId}/sessions/{sessionId}/fork")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"message\": \"Try the other approach\"\n}"

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

{
  "ok": true,
  "session_id": "0f8fad5b-d9cb-469f-a165-70867728950e"
}

{
  "error": "prompt_required"
}

{
  "error": "missing_bearer",
  "message": "Authorization required"
}

{
  "error": "missing_scope",
  "required_scope": "sessions:read"
}

{
  "error": "session_not_found"
}

{
  "error": {
    "type": "rate_limited",
    "message": "This API key exceeded its request-rate limit"
  }
}

Authorizations

Authorization

string

header

required

Your Reason API key from Settings > API. New keys use reason_; legacy ara_ keys remain accepted. Keys are capability-scoped: run, mcp:read, mcp:write, secrets:read, secrets:write, sessions:read, sessions:debug, knowledge:read, memory:read, memory:write, skills:read, skills:write, repos:read, repos:write, reviews:read, reviews:write, deployment:read, analytics:read, org:read, org:write, attachments:read, attachments:write, guardrails:read, guardrails:write, network:read, network:write, automations:read, automations:write, agent_auth:read. network:read and network:write are opt-in, excluded from default keys. network:read reads the saved workspace network policy; network:write replaces custom allowed hosts and requires a current organization owner/admin. Legacy project PATCH requests containing network_allowed_hosts also require network:write plus their existing run scope and project management permission; saved project hosts do not affect current session egress. Only owners/admins can mint or manage keys with network:write; keys cannot grant themselves more authority. See /docs/network-policies for replacement semantics and runtime applicability. mcp:write manages MCP server configuration only; it does not authorize remote MCP-tool execution. sessions:read reads sessions, including the assistant, reasoning and tool activity in their events. sessions:debug is privileged: only for organization owners/admins, it expands session events to the full diagnostic projection (diagnostic event kinds, status text and raw event metadata).

Path Parameters

orgId

string

required

Organization id or slug. Resolve it with GET /v3/self.

sessionId

string

required

The session id, returned as session_id by createSession and listSessions.

Body

application/json

message

string

The fork's first message. Without one the fork opens on the conversation so far and waits for a message.

title

string

Title shown for the new Session. Omitted, it is "Fork of" followed by the source Session's title, or "Fork of session" when it has none.

Maximum string length: 120

client_session_id

string<uuid>

A fresh UUID for the new Session; repeating it returns the first fork instead of making another.

Pattern:

^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$

Response

The fork's session_id.

boolean

required

Always true on success.

session_id

string | null

required

The new Session the fork created. Typed nullable with the admission receipt; a 200 carries an id.

Connect

Endpoints

Authorizations

Path Parameters

Body

Response