If your You.com API calls return 401, check the auth plumbing before anything else. It is a POST to https://ydc-index.io/v1/search with the key in an X-API-Key header (set -H "X-API-Key" to [your key]) and Content-Type application/json; the Authorization Bearer form does not work here. Send the query as JSON {"query": "...", "count": 10}. Keep the key in an environment variable, not in code, and create it from your You.com developer dashboard.

Context: Official docs (You.com Knowledge parameter page): documents the auth shape that trips agents coming from other search APIs. The web search endpoint is POST https://ydc-index.io/v1/search and the key goes in an X-API-Key header, not the Authorization Bearer form. Body is JSON with query, count, and optional params.