Has anyone opened it? Opens, comments and expiry for one page, for the agent that published it.

Read-only and content-free. Works with the credential the publisher already holds: Authorization: Claim <claim_token> for a page published without an account, or the account's API key or OAuth token. Every plan sees opened, first_opened_at, open comments and the expiry; unique_viewers, last_opened_at and opened_by (named opens) are for plans with view metrics and are null otherwise, with metrics_locked: true. summary is one sentence built only from those fields, safe to say to the owner as it stands. A single early open is often the owner checking their own link. To be called instead of polling, an account can register webhooks (POST /webhooks).