Instrument measuring UK

The sitegen site pipeline · self-test rack

This page is inspecting itself right now.

The needles are not a mock-up. They measure this very page in your browser, by the rules the pipeline uses before any site reaches a server. Flip a fault on the bench and watch a needle fall.

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Layout
Input
Style hash in CSP
Script hash in CSP
CSP violations0
Script errors0
Cost of one pass

Module 2 · faults from the lesson log

Fault bench

Each switch breaks the miniature page the way a real pipeline site once broke. The measurement is real. Turn the switch off and everything comes back.

L-005sg.layout

A line that will not wrap

Long text with wrapping forbidden runs past the edge, and a phone gets a sideways scroll.

measuring
L-108sg.a11y

A pale caption

Lighthouse scored accessibility 100, yet an independent check found captions that were hard to see. This text will become one.

measuring
L-024sg.lh

Dots of 8 pixels

Gallery dots so small a finger cannot hit them. The miniature's navigation shrinks to that size.

measuring
L-105sg.lh

An empty block filled late

A script adds a block after load, with no space reserved. A second later the content jumps down.

measuring
L-055sg.lh

Heavy work on the main thread

The page is busy and does not answer. Every 2 seconds the thread really blocks for 180 ms.

measuring
L-112sg.csp

A library from someone else's CDN

The page will try to load a script from a foreign host. CSP refuses it, and a real error appears in your browser console.

0
Page on the bench

Sample page

This invented scrap of a site exists to be broken. The main page stays under your control.

The longest line of this sample wraps quietly until wrapping is forbidden, and then it runs far outside the frame of the bench.

No faults. The bench log is empty.

Module 3 · chart recorder and counters

Tape

The recorder draws this page's readings once a second since you opened it. Marks on the tape are the switches you moved.

Meters within limitsThread blockingPast the edge

Pipeline counters

deploys

checks at the gates

lessons from errors

trap pages

deploys with an error on the live address

Snapshot of the deploys.jsonl log from 10 October to 4 November 2026, commit 5317d9b. A script counts these numbers, not a copywriter.

23 gates, and how many checks each has made

A lamp turns red when that gate would catch the fault you have on the bench right now. A page with that fault would not have left the pipeline.

Module 4 · construction

How it is made and what the instrument cannot know

Technique

  • The needle has a spring, but only a measurement sets its position. With reduced motion it lands without swinging.
  • The document walk is carried over from the checks/browser.mjs gate that runs on every site before a deploy.
  • crypto.subtle computes the inline style and script hashes in your browser, then compares them with the CSP header from the server.
  • The enamel is not a stock image: a 16-tone PNG is computed at build time from Voronoi cells.
  • The page passed the same gates it talks about: sg check, WebKit, Lighthouse.

Honest limits

  • The instrument measures only this page and only in your browser. It does not replace a full pipeline run.
  • A browser may give no LCP, CLS or longtask entries, as Safari can. Then the needle rests and the meter says there is no data.
  • Frame rate on a real phone and iPad has not been measured.
  • The bench shows how an error works on a miniature, not on the site where it happened.

What you just saw on one page, the pipeline does to every site. Sites in the portfolio: 62.

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