curl --request POST \
  --url https://harness.example.com/session-uploads/presign \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "harness": "<string>",
  "session_id": "codex-session-20260827",
  "sha256": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
  "size_bytes": 48217,
  "content_type": "application/x-ndjson"
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    harness: '<string>',
    session_id: 'codex-session-20260827',
    sha256: '0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef',
    size_bytes: 48217,
    content_type: 'application/x-ndjson'
  })
};

fetch('https://harness.example.com/session-uploads/presign', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://harness.example.com/session-uploads/presign"

payload = {
    "harness": "<string>",
    "session_id": "codex-session-20260827",
    "sha256": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
    "size_bytes": 48217,
    "content_type": "application/x-ndjson"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

{
  "upload_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "status": "pending",
  "headers": {},
  "upload_url": "<string>",
  "method": "PUT",
  "complete_url": "<string>"
}