Validate before share

Before sending the user any URL, preview, endpoint, build, or screen to open:

1. Verify yourself

• HTTP GET (or equivalent) on the URL
• Confirm 200 (or expected redirect chain ends OK)
• Confirm content matches intent: page title, hero text, JSON shape — not a generic health stub alone when the user cares about the product UI

2. Only share after pass

Do not say "try this link" or "should work" without evidence from step 1.

3. On failure

Fix or restart the environment, re-validate, then share. Report the effective URL (including port or path if different from default).

4. Production vs local