UI-realm live hazards

Correct behavior you have to know about. Things that are wrong live in ISSUES.md, one id each; things that are fixed live in git. If a rule here is pinned by a test that cannot be deleted quietly, it does not need to be here.

The index below is each hazard's rule; its section's reference file holds the rest — the mechanism, the measurement, and what it refuses. Read that file before changing code the rule is about. A term the rules use without defining (asSystem(), @system, callService) is one line in references/glossary.md under bridge-index.

Routes, prerender and static

Detail: references/routes-prerender-and-static.md

• The route table is a naming convention over a file tree, so it is committed too.
• A component rendered at BUILD time may import a sibling by relative path, and that had never worked.
• On a static target, dev is an SPA and the build is files, and only the build checks anything.
• A static route that produced no page fails the build where it was broken, and warns where it opted out.
• A server render answers every browser global as a wide desktop, so only a mobile-first branch bakes correctly.
• renderComponent reuses a compiled tree, so <script module> state is shared across every render in the process.
• The Shell draws the nav twice, and the drawer's copy is mounted while it is closed.

Tethers and records

Detail: references/tethers-and-records.md

• An entry is the synced truth for a row; a view remembers what it READ.
• A comparison between two independent record() views has THREE states, and drawing two of them is a screen that lies.
• A @from column moves when a CHILD row is written, and nothing announces the parent.
• A tether holds what its last load(query) asked for, so a patch can take a row OUT of it.
• @version is the revision a screen READ, and a push does not move it.
• A watched record empties itself on its own delete, before the handler's next line.

Resources and forms

Detail: references/resources-and-forms.md

• A write drops the columns the SERVER owns, and the version column is the one exception.
• A File column's control sends the bytes WITH the record, and there is no upload step.
• createResource coerces, blank-strips and validates by default.
• @system is the column an application writes and its caller does not
• <Form {resource} /> with no children IS the form
• find() answers the list envelope; invoke() answers exactly what the method returned (FJS-D937)
• tethered() is the one door a screen lists rows through; a route that calls service.find itself owns keeping it current.
• A resource's <script module> holds what the UI says about its model, so an enum's tone map lives there once.
• tethered().more() catches its error into .error, so a loop on hasMore alone spins on a failing call.
• A raw route is reached with client.fetch(path), which carries the client's credentials.

Mesa

Detail: references/mesa.md

• Everything a component reaches for is on $, and $ is legal only as the object of a member expression (FJS-D132)
• A Mesa instance <script> exports two kinds of thing: a prop and a method.
• On an ELEMENT bind: means the DOM writes back, so it is value, checked, files — plus group and this — and every other bind:x there is refused, naming x={expr} (FJS-D136)
• Mesa's scoped styles do not reach into child components.
• A component's stylesheet is ADOPTED, not appended, and an adopted sheet sorts after every <style> and <link> in the document.
• A block that reads a const derived from another const can mount a STALE value (FJS-1684)
• A const read off a getter is a constant, whatever the getter reads.
• A const that CALLS something with a let in its arguments is made again on every write to that let.
• Replacing a value notifies; mutating one does not — and o = o is the deliberate exception.
• An import is inert in a component with no $: of its own on it, and the default hint level says nothing about that.
• A function hides its reads from the compiler, which costs a subscription and an ordering.
• A $: block is woken by what it reads from outside itself, never by its own writes. A called function that does ++seq subscribes the block to seq; the write is ignored while the block runs (FJS-2652), so a state change made BY the block is not a trigger for it.
• A $: dep, handler does not run at mount, and its prev is the same object when the change was a mutation.
• A watched object cannot be cloned or spread out of its proxy — unproxy() it.
• An unkeyed {#each} is keyed by INDEX, so a row's DOM state stays with the position after a reorder.
• null renders as nothing, but false means three different things depending on where it lands.
• A type="number" or "range" input binds a NUMBER, and an empty box binds undefined.
• In a .md file {…} interpolates a bare path only; anything else stays literal text, with no error.
• A compiled component called directly instead of through mount() renders and never answers a click.
• A prop a component does not declare is not an error: it is the component's $attributes, spread onto its root element (FJS-1648) — fli check's kit-prop-unknown grades kit components
• A parent sends a prop only when ITS value changed, so re-sending the same value does not reset a child's own edit (FJS-2589)
• A component reaches the DOM through nodes it owns.

Driving a browser

Detail: references/driving-a-browser.md

• An overlay that is present is not an overlay that is visible.
• Headless Chrome delivers almost no rendering lifecycle after load.
• Headless Chrome answers (hover: none) and (pointer: none).

Build output and @frontierjs/css

Detail: references/build-output-and-frontierjs-css.md

• Vite injects the built <script> at the first textual match for the body tag and does not skip comments.
• A var() naming a token nothing defines drops the whole DECLARATION
• A class name is not checked by anything
• A code sample highlighted with prefix: true loses its first character.
• An inline style= carries a custom property and the <style> block reads it.