Body keypoints, 17 joints,one API call.

import os, requests
from pathlib import Path

resp = requests.post(
    "https://api.msightflow.ai/v1/pose",
    headers={"Authorization": f"Bearer {os.environ['MSF_API_KEY']}"},
    files={"image": Path("athlete.jpg").read_bytes()},
    data={"return_overlay": "true"},
)
for p in resp.json()["persons"]:
    nose = p["keypoints"][0]            # COCO index 0 = nose
    l_wrist, r_wrist = p["keypoints"][9], p["keypoints"][10]
    print(f"person bbox={p['box']}, nose={nose}, wrists={l_wrist}, {r_wrist}")

import fetch from "node-fetch";
import FormData from "form-data";
import fs from "fs";

const form = new FormData();
form.append("image", fs.createReadStream("athlete.jpg"));
form.append("return_overlay", "true");

const resp = await fetch("https://api.msightflow.ai/v1/pose", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.MSF_API_KEY}` },
  body: form,
});
const { persons } = await resp.json();
console.log(`${persons.length} persons, total keypoints: ${persons.reduce((n,p)=>n+p.keypoints.length,0)}`);

curl -X POST https://api.msightflow.ai/v1/pose \
  -H "Authorization: Bearer $MSF_API_KEY" \
  -F "image=@athlete.jpg" \
  -F "return_overlay=true"

# Compute elbow angle for form analysis (rep counting, ergonomics).
import numpy as np

def angle(a, b, c):
    ba, bc = np.array(a) - np.array(b), np.array(c) - np.array(b)
    cos = np.dot(ba, bc) / (np.linalg.norm(ba) * np.linalg.norm(bc))
    return float(np.degrees(np.arccos(np.clip(cos, -1, 1))))

person = resp.json()["persons"][0]
kp = person["keypoints"]
# COCO indices: 5 left-shoulder, 7 left-elbow, 9 left-wrist
l_elbow_angle = angle(kp[5][:2], kp[7][:2], kp[9][:2])
print(f"left elbow flexion: {l_elbow_angle:.1f}°")