# Pexels 股票适配器在每次请求中都失败——缺失 " User-Agent " 头条(Cloudflare 401/403)

Summary

tools/video/stock_sources/pexels.py sends requests to the Pexels API and CDN with no User-Agent header. The default Python (Python-requests/x.y.z) is blocked by Pexels' edge (Cloudflare), so every search returns 401 Unauthorized / 403 Forbidden even with a valid PEXELS_API_KEY. Adding a browser-like UA makes the identical key return 200.

Impact

• direct_clip_search and corpus_builder return zero clips whenever Pexels is a source.
• Preflight (provider_menu_summary()) reports Pexels as configured because the env var is present, so the failure only surfaces mid-run at the asset stage.
• Blocks the documentary-montage pipeline (Pexels is its primary source) and any pipeline relying on Pexels stock.