Page Serve

page-serve, give a human a URL

An agent that renders a page for a human needs a way to hand it over. The pattern that grew in sessions was python3 -m http.server 8991 plus portless alias <name> 8991 typed by hand: no record of the process, no stop, servers outliving the session, and one measured night (2026-09-06) where the same session did it twice and the server was still up the next morning. This skill is that pattern with a state file, a stop, a status, and a loud failure when the URL contract cannot be met.

The contract

• The URL is https://<name>.localhost/<file>. No port, ever. portless's 443 service owns the port; a :1355 or :8991 in the URL is the pre-service fallback and the skill refuses rather than emit one.
• One static server per name, on a free loopback port, rooted at the file's directory (so sibling assets resolve) or at the directory you pass.
• State in .claude/state/page-serve/<name>.json: root, file, port, pid, url, time. status re-measures pid, route, and HTTP on every call; it never trusts the file.
• Idempotent per name: same name + same root reuses the live server; a different root replaces it; --force on the alias overrides a stale route with the same name.

Usage

page-serve docs/playgrounds/roadmap-2026-09-07.html
page-serve docs/playgrounds/ --name playgrounds
page-serve <path> --screenshot          # agent-browser, returns the png path
page-serve status [--json]
page-serve stop <name>
page-serve stop --all

serve.sh prints url=, name=, port=, pid=, http=, optional screenshot=, and the exact stop= line to paste. Put the url= line in your reply's Open section.

Modes

Failure modes, all loud

A page that "served" but does not answer 200 through the proxy is exit 4, not 0, so a caller that only reads the exit code cannot report a dead link as done.

Screenshot

With agent-browser installed the default is to take one (--no-screenshot to skip; --screenshot to insist and get a stderr line if it is missing). The png lands beside the state file. The screenshot is evidence the page rendered, not proof it rendered correctly: read the image before claiming the page looks right (the glyph skill's rule 1).

What this is not

• Not a dev server. For a framework app with hot reload use dev, which wraps the app's own dev command in portless. This skill serves static files.
• Not a publisher. Nothing leaves the machine; .localhost resolves locally only.
• Not a docs-site deploy. Lab pages under docs/site/public/lab/ still ship through the docs-site build; this skill is for the hand-over before or beside that.

Retiring the old pattern (#3900)

Any skill or page that tells an agent to run python3 -m http.server or to type portless alias by hand should say page-serve <path> instead. As of this skill's first release, grep -rln 'http.server' src/skills is empty; the pattern lived in session habits and in hq-ext, so the sweep is glyph, playground, visualize-plan and expect (the four that hand a human a page) plus hq-ext's glyph.

Related skills

• dev, the dev-loop sibling for framework apps (portless wrapping a dev command)
• portless (the reference skill, model-invoked): service install, LAN mode, gotchas
• glyph, visualize-plan, playground, the producers of pages this serves
• expect, browser verification against the URL this prints