Retrieve file content

You're Claude Code, working in my repository.

Task
Add a download_file helper to my app that streams GET https://api.meta.ai/v1/files/{file_id}/content to a local path as raw bytes.

Read this first
Meta's docs page "Retrieve file content" as Markdown: https://dev.meta.ai/docs/api-reference/files/retrieve-file-content.md
It's the source of truth for request and response shapes. The same page for people: https://dev.meta.ai/docs/api-reference/files/retrieve-file-content

Setup
- Base URL: https://api.meta.ai/v1
- Auth: send Authorization: Bearer $MODEL_API_KEY, reading MODEL_API_KEY from the environment. Never hard-code, print or commit the key.
- Model: muse-spark-1.3-contributor (Contributor mode: Meta may use what you send to train future models; drop -contributor for Standard mode)
- Python: the OpenAI SDK (pip install openai) with base_url="https://api.meta.ai/v1" and api_key=os.environ["MODEL_API_KEY"] works, or plain requests.

Facts to get right
- The reply is the file's raw bytes (application/octet-stream in the reference), not JSON: write it in binary mode and stream large files.
- file_id is a required path parameter. The metadata (filename, bytes) comes from GET /v1/files/{file_id}.
- A deleted or unknown id answers 404.

Starter code (Python)
import os

import requests


def download_file(file_id, path):
    with requests.get(
        f"https://api.meta.ai/v1/files/{file_id}/content",
        headers={"Authorization": f"Bearer {os.environ['MODEL_API_KEY']}"},
        stream=True,
    ) as response:
        response.raise_for_status()
        with open(path, "wb") as f:
            for chunk in response.iter_content(chunk_size=1 << 16):
                f.write(chunk)


download_file("file_abc123", "copy.bin")

Done when
- download_file writes a file whose size matches the FileObject's bytes.
- The downloaded file opens like the original.
- The key comes from MODEL_API_KEY and never appears in code, logs or commits.
- API errors (4xx, 429) surface their message instead of failing silently.