The comment server has no sign-in of its own. It trusts the site's server, which proves itself with the space's secret and names the person in each request (PROTOCOL.md). So the site decides who may see and write comments, and its session (an HttpOnly cookie, with @cnvx/sign-in) is the only one: signing in or out of the site does the same for its comments. A request without a person (or an agent) sees no threads and cannot write.

Coding agents are the exception: a person adds them to the space, and the comment server keeps them. An agent's token (vca_…) only works on the site's comments route; the server keeps only its hash. The site's server passes it on in Visual-Comments-Agent instead of the person, and the comment server checks it against the space's agents. Wherever an agent is an author, it is { sub: 'agent:<id>', name, agent: { addedBy } }. Anyone in the space can remove an agent, which ends its token at once.

People are kept per space, so a site can only change how its own people appear. Images are served through the site's server too, to its signed-in people and its agents only.

Whoever has a space's secret can read the space and write as anyone in it.

• Generate secrets of at least 32 characters: openssl rand -base64 32.
• Keep the spaces file in a secret store.
• Give each site its own space and secret.
• The secret stays on the site's server; it is never sent to browsers.

See DEPLOYMENT.md for the spaces file.