Part of Decisions. Each decision has a name, which issues and code comments use to refer to it.

Biome 2.5.15 reports import { Suspense } from "react" under noUnresolvedImports (biomejs/biome#10283). Axlog chose (2026-10-10) Next's segment conventions instead of inline <Suspense>: each route's static shell sits in the segment's layout.tsx, the page holds only the data-dependent part, and loading.tsx holds the fallback. No code imports Suspense, and the rule stays on.

The header's signed-in links come from a root parallel slot, src/app/@header/, that reads currentUser() (orchestrator, 2026-10-12). The header blocks on that session read, so it arrives whole, links and all, in the page's first HTML (Axlog, 2026-10-14, #106). The slot has no loading state, and the root layout sets instant = false, which turns off Cache Components' static-shell check for the whole app: every page renders per request, so /, /login, /settings and /signup are no longer partial prerenders. Each page's own content still streams behind its segment's loading.tsx. The slot's error.tsx keeps a database failure to the page's own error, shown once. Rejected: streaming the links in after a prerendered shell behind hidden placeholder copies (the earlier choice), because the header loaded piecemeal and, without JavaScript, never got its links; rendering SignedInLinks straight in the root layout (a database error there would fail the whole page, with no global-error.tsx); client links reading usePathname() (the build fails outside <Suspense>); static links by route (stale after signing out everywhere, and a second copy of the public paths); a public /settings; null slot pages that would repeat the public paths.

A compact signed-in header (Axlog, 2026-10-13, #17): on an iPhone 15 it takes at most 2 rows in every theme, and 1 where it fits. Below sm the header has tighter spacing (px-4, gap-2) and the theme picker's trigger shows only its icon, its name kept for screen readers. Its buttons stay 44 px tall, and the site's name stays a line of text tall, above WCAG 2.5.8's 24 px. Rejected: a menu button that hides Settings and Account.

The links are Chat (the central chat, /chat) and Projects (#309, central-chat), then Buddies (#80; once Personas), Settings and Account, in that order, then the theme picker. The links take px-2 below sm. Until #309 the three links and the picker kept to one row under the site's name; five links and the picker don't fit one row on an iPhone 15, so below sm the links' wrapper is contents and they flow on from the site's name's own row (which grows to a button's height) and wrap after it, still at most 2 rows in every theme (site-header.browser.test.tsx). From sm up the wrapper is a row of its own beside the name, 1 row on a laptop. At 320 px, where the ruling sets no row target, the header may take a third row rather than the page scrolling sideways.

The chat is built from assistant-ui primitives (@assistant-ui/react with @assistant-ui/react-ai-sdk), not copied registry components, so only our thin wrapper is linted (Axlog, 2026-10-11). It renders custom parts through MessagePrimitive.Parts. Risks: it is 0.x with daily releases (versions pinned), and it keeps a second state store mirroring useChat. Rejected: Streamdown alone (not a chat UI), copied Vercel AI Elements (250–600 Biome diagnostics), and CopilotKit, Deep Chat, NLUX, chatscope and LlamaIndex chat-ui.

Radix Primitives through the unified radix-ui package, styled with our own tokens, cover every design element of the site (Axlog, 2026-10-11). It is an npm dependency, so Biome doesn't lint it. assistant-ui stays for the chat's behaviour. Rejected: shadcn/ui (on Radix or Base UI: copied code that Biome lints, plus cva, clsx and tailwind-merge) and Base UI alone.

Orchestrator, 2026-10-12, on Axlog's requests.

• Breadcrumbs stay reachable in long chats: the chat page's header (breadcrumbs and title) stays pinned while messages scroll, compact on phones. The chat name stays clamped to one line there; the full name shows in the chat list and the Rename field. Rejected: breadcrumbs under the composer, a "back to top" button, a two-line name on phones (the header would reach about 25% of an iPhone 15 screen) and a title (hover-only).
• Feature flags for extras, on by default, switched by the user: one registry in src/flags/; /settings switches them off; <html data-hide>, set before paint from the cookie, hides tagged elements through the last cascade layer, extras. Hiding is display only. Extras: working notes, memory change cards, tool lines, the pinned header, chat names in the chat list, page decorations, the usage meter, a persona's prompt mechanics parts, and the interview persona picker. The persona mechanics and interview persona extras are the two off by default (issues #104, #108). Citations, the persona label and the composer are not extras. Rejected: deploy-time flags only Axlog controls.
• Mobile is supported: every page works on phones. Both chat pages, /chats/[chatId] and the central chat's /chat, export a viewport that sets interactiveWidget: "resizes-content"; dynamic viewport units were rejected because the document scrolls and the composer is sticky.

A reload during a reply loses the live reply (orchestrator, 2026-10-12; issue #52). The server still finishes and saves the reply, but the reloaded page shows only her message until she reloads again after the reply is saved. This is a known limitation in version 1. Deferred, not rejected: resumable streams (they need a shared stream store) and a "still replying" state that picks the reply up (it needs a way to tell a reply in progress from a failed one, which also shows as her message with no reply).

Themes are Gravy Falls (the default), Ghost Hasslers and Ay, Liens!, spoofs of Gravity Falls, Ghostbusters and Aliens, each with Light, Dark and System (Axlog, 2026-10-11). Components read semantic tokens; themes only define them. The choice lives in a cookie (per browser, not per account), applied by a pre-paint script, so the HTML needn't depend on it; the proxy reads it only for font preload headers (below). The cookie is written by a Server Action (saveThemeChoiceAction) with no account check, so it is saved in every browser and on signed-out pages. Rejected: the Cookie Store API, which is missing in browsers from before 2025 and on pages not served over HTTPS or localhost (#42).

Theme fonts are self-hosted from apps/web/src/themes/fonts/<family>/ via next/font/local: latin, wght-only variable woff2 files, each with its OFL.txt, copied from the @fontsource-variable packages (#123; @axolotl-logic, 2026-10-14). Rejected: next/font/google, which fetches from Google Fonts at build time, and fontsource as a dependency.

The server's rendering never reads the theme cookie, and the HTML is the same for every visitor. The proxy (apps/web/src/proxy.ts) reads the cookie only to send a Link header that preloads the saved theme's fonts on every page it lets through (not /api/*, redirects or 401s); a missing or unknown theme preloads Gravy Falls' (#124, 2026-10-14). No font preloads through next/font (preload: false on every font). The URLs come from the committed apps/web/src/themes/theme-font-urls.ts, regenerated from a production build's @font-face rules after a font file, its options or Next's version changes; npm run check:build-fonts (apps/web/scripts/check-build-font-urls.ts) checks them against the build's @font-face rules: npm run test:e2e runs it after its build, before starting the server, and it fails on any drift or when there is no built CSS. It is a script over .next/static/**/*.css, not a Playwright test, so e2e-visual-and-auth-only is unchanged (#348, 2026-10-17; it replaced the check in e2e/theme-font-preload.spec.ts). Rejected: (a) reading .next manifests at runtime, since next/font's manifest lists only preloaded fonts (none) and it ties the proxy to build internals and the filesystem; (b) keeping next/font's own preload, which goes in the shared HTML, so every visitor would also get the default theme's fonts; (c) preloading every theme's fonts; (d) choosing preloads in the pre-paint script, ruled out by @axolotl-logic; (e) cookies() in the layout, which loses the prerendered shells. The theme picker also preloads a theme's fonts on the client when its option is pointed at or focused (not the applied theme's), with ReactDOM.preload and the same theme-font-urls.ts map, so choosing it shows no fallback font; the shared HTML and the pre-paint script are unchanged (#125, 2026-10-14).

Each theme sets its own spacing unit, which Tailwind's --spacing follows (Axlog, 2026-10-11): Gravy Falls 0.25rem, Ghost Hasslers 0.28rem, Ay, Liens! 0.22rem.

Each theme sets its own heading sizes, read by page-roles.css (Axlog, 2026-10-12). Ay, Liens! uses smaller headings, so the login title stays on one line and "Project memory" stays beside a long project name. In Gravy Falls, Axlog accepted that the link drops below a project name of 37 or more characters; the heading test uses 36 there and 40 in the other themes. Ay, Liens!'s danger reads as red in both modes.

Times (formatTime, LocalTime) are fixed-length and set in the theme's monospace font with tabular figures (Axlog, 2026-10-13, #58): the day and 12-hour clock hour are zero-padded and months are three letters, as in Oct 02, 2026, 08:16 PM. The server's unseen UTC placeholder is then as wide as the browser's local time, so the line does not shift on hydration. The day and the clock are formatted apart and joined with ", ", because engines join them differently: WebKit writes Oct 12, 2026 at 08:16 PM, which is longer than the server's placeholder (found by the zoned browser test, #140). Rejected: reserving a fixed box for the time, rendering the browser's zone on the server from a cookie, and accepting the shift.