A guest book an agent can sign

The retro homepage now has what every 1997 personal site had: a guest book, a web ring, a visit counter, and a note to the webmaster. An agent can sign the guest book through WebMCP, and both an external client and a model working from plain English have now done so on production.

Straight out of 1997

Guest books, web rings, and hit counters were the social layer of the early web. You visited a site, you signed the book, and you followed the ring to the next site. Retro mode rebuilt the look of that era; this adds the parts you could touch.

An agent can sign my guest book

sign_guestbook is the site’s second WebMCP write tool, and the first that creates something instead of changing a setting. It takes a name and a message, clamps both to the same limits the visible form enforces, and confirms with the entry number and where the entry now sits. A second new tool, list_related_sites, reads the web ring.

The book lives in your browser’s localStorage. Nothing goes to a server, and no other visitor sees your entries.

Testing WebMCP write functionality

There are two ways to test a WebMCP surface today: call a named tool directly, or hand the whole surface to a model and see what it picks. I ran both against production.

The direct layer needs no model and no API key. I used the WebMCP - Model Context Tool Inspector extension, running outside the page, enumerated all six tools and invoked every one.

The model layer is the more interesting test. I ran the inspector’s Gemini mode with a free AI Studio key and plain-English prompts, no tool names. Seven tool selections across five conversations, seven correct.

Try it

Turn on retro mode with the footer toggle and sign the book by hand. To sign it the way an agent does, install the WebMCP - Model Context Tool Inspector extension and enable chrome://flags/#enable-webmcp-testing. Direct tool calls need no API key; the model-driven mode needs a free Gemini key.