booth/docs/contracts/r2_flow.contract.md

---
contract_version: "0.2-BUILT"
status: "BUILT 2026-09-23 on design-dev/svos-retheme (C1-C7, TDD), awaiting heid code-review and bug-hunt before the hand-over to booth-dev. PROPOSED 2026-09-23 by design-dev. Ruled by the operator the same day in the `flow` mark on booth-flow-concepts (direction a_b; compare MODE to be built in this arc; voice plain; emblem no), relayed via Miranda → booth-dev, verbatim at docs/rulings/. Compare mode is NOT in this contract: it lands after this one as r3, as a view toggle over the same item record."
module: "booth.app + booth.items + templates (the review flow)"
purpose: "Make the Booth a place where judgment happens rather than a place where files are shown. The operator's bar is 'did anything change when I opened it'. A reskin cannot clear that bar; this contract changes the flow. There are three surfaces and one plumbing change. THE DESK: the index triaged by what needs the operator. THE LIGHTBOX: a booth page with the set on the left and the verdict beside it. THE REVIEW: full size with the judgment on screen, a filmstrip, and seen-tracking. The plumbing is IN-PLACE JUDGMENT: a mark POST that does not reload the page or eject you from full size."
depends_on:
  - "booth.items.booth_items + Item (INV-1: the one resolver). Item gains `ordinal`, derived there and nowhere else."
  - "booth.items.image_chain (the zoom ring). SUPERSEDED for the review route by `review_chain`; image_chain stays importable and unchanged for its existing callers and tests."
  - "booth.app._newest_mtime (THE definition of activity — booth-dev, 2026-09-23). The Desk's 'last activity' reuses it verbatim. The Desk's 'landed since you looked' is a DIFFERENT question and gets a DIFFERENTLY NAMED helper; see INV-5."
  - "booth.app.record_view / VIEW_MARKER (`.viewed`, U4). The Desk reads its mtime to answer 'new since you looked'."
  - "booth.app.hold_read / hold_reason / open_marks (INV-2 of U2: the one openness predicate). 'Needs you' is `open_marks(...)` non-empty, or `hold_reason(...) == \"unreadable\"` (C4); nothing else."
  - "booth.marks.as_dict, set_flag, write_note, answer_pick, delete_mark (the write API, UNCHANGED)."
  - "booth.app._mark_redirect (the 303 landing). Extended with one new `back` value; the existing two landings stay byte-identical."
  - "booth.benches.read_benches, booth.links.parse_link_entries / order_for_display / booth_target (the Desk's side column)."
language: "python + jinja + a little javascript"
complexity: "high"
estimated_loc: 900
confidence: 0.6
used_by:
  - "booth.app.index (the Desk)"
  - "booth.app.booth_view (the lightbox)"
  - "booth.app.booth_view_file (the review)"
  - "booth.app.booth_answer / booth_note / booth_flag / booth_unmark (in-place judgment)"
touches:
  - "booth/items.py (Item.ordinal; review_chain; read_seen/SEEN_FILE)"
  - "booth/app.py (list_booths fields; index sections; booth_view verdict data; booth_view_file review context + record_seen; wants_json + 204; _mark_redirect `back=view`)"
  - "booth/templates/index.html (REWRITTEN as the Desk)"
  - "booth/templates/booth.html (restructured: two panes; the marks panel moves into the verdict aside; tiles carry ordinals; inline group headers)"
  - "booth/templates/view.html (REWRITTEN as the review: stage, rail, filmstrip, tape)"
  - "booth/templates/_marks.html (renders inside the aside; flag list ordered by ordinal)"
  - "booth/templates/base.html (layout CSS; the in-place script)"
  - "booth/templates/doc.html (NOT restructured — a doc keeps its reading page; named because it was checked)"
  - "booth/static/embed.js (NOT TOUCHED — the verbatim path keeps its author's layout; requirement 6)"
  - "tests/test_booth.py (THREE assertions change, all in test_index_separates_kept_from_ephemeral: L785-786, the kept-lane presence pair, and L789, kept-before-ephemeral. L810-811, the absence pair, survive unchanged. See 'Assertions that change')"
  - "tests/test_flow.py (NEW)"
  - "tests/test_embed_browser.py (ONE test changes: test_the_keyboard_flag_actually_submits expected a navigation, which is the defect R2 removes. See 'Assertions that change')"
assumptions:
  - "ONE VIEWER. `.seen` records what has been seen at full size, not WHO saw it. ROADMAP parks 'per-viewer state (who has seen what)' on the one-viewer premise; this contract keeps that premise and does not reopen the parked item."
  - "EVERY JUDGMENT WORKS WITH JAVASCRIPT OFF. Each control stays a plain <form method=post>. The in-place behaviour is additive and falls back to today's 303."
  - "THE VERBATIM PATH IS OUT OF SCOPE. A booth with its own index.html is served as the author wrote it (requirement 6). The Desk links to it; the lightbox never renders for it."
  - "NO THUMBNAILS. Tiles, the filmstrip and the Desk's preview strip use the original files with loading=lazy. Progressive loading stays parked until page weight is measured."
open_questions:
  - "ANSWERED BOOTHS LOSE THEIR HOLD (raised by booth-dev in b46ac02). A booth is held while its question is open, so it becomes sweepable the moment it becomes a decision record. The flow question: should an answered pick hold its booth for a grace period, or should the record live elsewhere? NOT SOLVED HERE, because it is a lifetime-policy change and this contract changes no lifetime rule. Raised separately."
  - "KEY 1–9 TO ANSWER A PICK from the review rail. It appeared in the concept mock. Dropped from this contract: multi-question picks make the mapping ambiguous, and the operator ruled the flow, not the keymap. Parked."
---

# R2 — the review flow: the Desk, the lightbox, the review

## The requirements this answers (from the round-2 README, uncorrected by the operator)

| # | requirement | answered by |
|---|---|---|
| 1 | show me what needs me | the Desk's *needs you* section |
| 2 | picking winners is the main judgment | the lightbox's flag tray; F in the review |
| 3 | flag without losing my place | in-place judgment + `back=view` |
| 4 | position is identity (within the set as it is now — not a durable id) | `Item.ordinal`, printed on every tile |
| 5 | the question stays beside the work | the verdict aside (sticky) |
| 6 | reports keep their author's layout | verbatim path untouched |
| 7 | listening sets are real | `review_chain` includes audio and video |
| 8 | lifetime is not an organising principle (it is still SHOWN as a fact on each row; it no longer GROUPS or SORTS) | the Desk drops the kept/ephemeral lanes |

## Terms used below

- **Reticle**: the SVOS selection mark in base.html — four corner brackets drawn
  inside a box. It marks the one current or selected thing and nothing else.
- **Tape**: a row of small segments, one per item in the review ring, each
  showing *seen*, *flagged* or *current*.
- **Stage**: the area of the review page where the artifact itself renders.
- **All Booth state files are dotfiles.** That covers `.marks.json`
  (MARKS_FILE), `.viewed`, `.blurred`, `.seen`, `.forever`, `.pins`,
  `.booth.json` and every `*.lock`. "Non-dot entries" means the posted content
  and nothing the Booth or the operator wrote.

## Components

### C1 — `Item.ordinal` (items.py)

`ordinal: int` is the item's 1-based position in `booth_items(booth)`, i.e. in
`sorted(rel)` order over **all** items. It is assigned in the resolver loop, so
no route derives it.

- `ordinal` is **appended** as the dataclass's last field, never inserted.
  Mid-dataclass insertion is a positional-construction break, and `group` has
  already had that conversation.
- The resolver's `quote()` guard on non-UTF-8 names stays exactly as it is. It
  looks like a stray `try` around a discarded result, but it is what keeps one
  0xff filename from taking down the index for every booth.
- An item skipped by that guard takes no ordinal, so ordinals stay contiguous
  over the items that render.

- **A filter never renumbers.** Under `?filter=flagged` a tile still shows the
  number it has in the whole set. That is the point: "#07" is a property of the
  item, not of the view.
- **A new file renumbers everything after it.** That is honest, and it matches
  the order: the operator's positional references are to the set as it is now.

### C2 — `review_chain` and `.seen` (items.py, app.py)

- **`review_chain(items)`**: the rels of items whose kind is image, video or
  audio, in item order. ONE LINE: *the item order filtered to media.* It
  replaces `image_chain` as the review route's prev/next ring.
  - It is a **declared change** to the zoom-ring rule. Today's ring is images
    only. A booth mixing images and audio now rings through both, in set order.
  - `image_chain` stays for its callers and tests.
- **`SEEN_FILE = ".seen"`**: a UTF-8 JSON array of rels. Not one rel per
  line, `.blurred`'s shape: a file name may contain a newline, and a line format
  would split one such rel into two, neither of them real.
  - Written by `record_seen(booth, rel, items)` from the review route, below the 404s
    and gated on the item record — the same gate `record_view` has.
  - Each write rewrites the whole file: the previous set plus `rel`, minus
    rels no longer in `booth_items`, sorted. It is deduplicated and pruned, so
    it never grows past the booth's item count.
  - Atomic replace, per the Booth's CLAUDE.md invariant 5 ("sidecar writes are
    atomic"), not this contract's INV-5.
  - Seen is keyed by rel. A file replaced at the same path stays seen; a
    deleted file drops out at the next write, and every count below
    intersects with the current `review_chain`.
  - **The review route ALSO calls `record_view` (existing U4 behaviour,
    unchanged).** So reviewing a booth at full size refreshes "you looked" for
    the Desk exactly as opening its grid does. `.viewed` and `.seen` never
    disagree about whether you looked at the booth; `.seen` only adds WHICH
    items.
  - NEVER RAISES, like `record_view`: failing to record a look costs the
    marker, not the page.
- `read_seen(booth) -> set[str]` is lenient and NEVER RAISES. It opens without
  following a symlink and without blocking, reads only a regular file of at
  most 1 MiB, and keeps only the array's string members. Anything else — a
  link, a FIFO, a directory, an oversized, malformed or too-deeply-nested
  file — reads as the empty set. `.seen` sits in an agent-writable directory, and a planted FIFO
  must not hang the review route.
- `items` is the route's own `booth_items` result. It is passed in so that the
  prune ("minus rels no longer in `booth_items`") costs no second walk.
- **Seen is UI state, not judgment.** It is not exposed in `marks.json` and it
  holds nothing.
  - It adds no lifetime RULE. Being a dotfile, its write does move
    `_newest_mtime`. So does the `.viewed` write on the same request, so a
    review page ages a booth exactly as it does today.

### C3 — in-place judgment (app.py, base.html)

**`wants_json(accept: str | None) -> bool`** takes the raw `Accept` header, so
it is a pure function a test can call directly. It is True **only** when the
header, split on commas, contains an entry whose media type, parameters stripped, is
exactly `application/json` and whose q-value is absent or greater than 0.

- Absent, empty, `*/*` or `application/*` → False.
- `application/json;q=0` → False. A client that explicitly refuses JSON gets
  the redirect.
- A near miss such as `application/jsonx` → False.
- **Every entry is parsed before anything is decided.** One unparseable
  entry anywhere, before or after a good one, makes the whole header False.
- Any header that fails to parse → False. A q-value that is not a finite
  number (`q=nan`, `q=inf`) fails to parse.
- **It fails toward the 303.**

The four mark routes (`/answer`, `/note`, `/flag`, `/unmark`) perform the same
write as today, then:

- `wants_json` → **204 No Content**.
- otherwise → today's `_mark_redirect(...)`, **byte-identical**: same status,
  same `Location`, same body.

**`back=view`** is a new landing for `_mark_redirect`, carried by the review
route's forms together with `f=<rel>`. It lands on
`/b/<name>/view?f=<quote(rel)>#rail`. This fixes the JS-off bounce too:
today's zoom flag form carries no `back`, so it lands on the gallery.

- `back=view` lands on the review only when `f` names an item in
  `review_chain`, i.e. a media item. For anything else (a doc, a missing rel,
  an empty `f`) the landing falls back to the booth page, exactly as a form
  with no `back` does today. `doc.html` carries no forms, so no shipped page
  sends `back=view` with a doc.
- The URL is built server-side from `name` + `quote(f)`, never echoed, so this
  is not an open redirect.

**The client**: one small script in base.html, bound to forms marked
`data-inplace`.

1. POST the form with `Accept: application/json`.
2. On 204, GET the current URL and replace **every** element carrying
   `data-region="<id>"` with the same-id element from the response.
   - The rule is "every region whose content can depend on marks is a
     region".
     - On the lightbox: the verdict aside, each tile, the rail (its filter
       counts change when you flag), and the header's open count and lifetime
       line (`booth-status`).
     - On a booth with marks but no set: the panel (`marks-panel`).
     - On the standalone marks page: the header's open count (`booth-status`)
       and the panel (`marks-panel`), one region around both its states so
       answering the last mark away swaps in the empty state.
     - On the review: the rail, the filmstrip and the tape.
   - The stage is never a region: replacing it would restart a playing video
     or audio track.
   - A TILE (`item-*`) absent from the response is left alone and never
     deleted. Deleting it would shift every tile after it under the reader's
     eye. It is marked `is-stale` so it does not pass for current:
     un-flagging under `?filter=flagged` is the case. The next navigation
     drops it.
   - Any OTHER difference in structure — a non-tile region in the response
     that the page lacks, or one the page has that the response lacks — or a
     page with no region to swap at all, is not patched: the script reloads
     with a GET, so what you see is the server's truth.
   - The swap also carries the per-viewer state a reload would have reset
     but an in-place save must not:
     - live media whose src is unchanged;
     - a revealed blur;
     - a closed doc;
     - disclosures the reader opened or closed;
     - every DIRTY control: a half-typed or edited note, a radio picked and
       not yet sent.

     All of it is matched by IDENTITY, never by position: a form by its
     action and its hidden `ask`/`target`/`mark`/`f` fields, a control by its
     form plus its name (plus its value for a radio or checkbox), a disclosure
     by the pick or form it holds. A flag that adds a tray row above a draft
     must not move the draft into the wrong box. The form just sent is the
     exception: its fields come back as the server rendered them, and its
     disclosure comes back folded.
3. **Saves are SERIALIZED.** Each save runs its POST, its GET and its swap
   before the next begins, so an older snapshot never lands after a newer one
   (three quick flags show three flags). A form already queued or in flight
   ignores another submit: a double-click writes one note, not two.
4. **The script never re-POSTs.** A retry after a lost response would re-apply
   the judgment: a duplicate note, or a re-dated answer.
   - On a non-204 HTTP response, or a network failure, it writes a fixed
     message into the page's server-rendered status element
     (`data-region="status"`, via textContent). After a beat (0.9 s, so the
     words can be read) it reloads the page with a GET, so what you see is the
     server's truth.
   - The one case where a non-JS submit happens is a script that cannot run at
     all. That is the plain form.

**The server renders every state; the script only places it.** This is U3's
rule — a second renderer in JavaScript would be the same bug in a new language.

### C4 — the Desk (index.html, app.index, list_booths)

`list_booths` gains five fields, all read in the one pass it already makes:

- **`open_since`**: the `created` of the OLDEST open pick in the booth, or
  None. Computed via `open_marks`, INV-2.
  - `Mark.created` is a STRING. It is parsed with `datetime.fromisoformat`,
    never compared lexically: two ISO stamps with different offsets, or a
    legacy-import stamp, sort wrong as text.
  - An unparseable stamp sorts AFTER every parseable one, and name breaks the
    tie.
- **`flags`**: the number of CURRENT items carrying a READABLE flag mark,
  shown on every Desk row that has any — `flagged_targets(marks)` intersected
  with the booth's item rels. `flagged_targets(marks)` is the ONE flag
  predicate. The Desk, the tray, the orphan list, the rail's `flagged` filter,
  the tiles, the filmstrip, the tape and the review button all read it, and an
  unreadable flag entry counts nowhere. A flag whose file
  has since been deleted is an ORPHAN: it counts on no Desk row, and the tray
  lists it (C5) so it can be cleared.
- **`landed_at`**: the newest mtime among the booth's CONTENT — its regular
  files and symlinks with no dot-component in their path, each read by
  `lstat`. **Deliberately not `_newest_mtime`** (INV-5). Five refinements,
  each load-bearing:
  - **Files only, never directories.** Creating any dotfile (`.viewed`, the
    marks file's temp-and-replace) bumps the booth directory's own mtime, so
    counting directories would make the flag you set after looking read as a
    delivery.
  - **A symlink counts by its OWN mtime** — when it was placed — never its
    target's. A link to a busy file outside the booth must not make the booth
    read as newly delivered.
  - **An empty booth landed at 0.0.**
  - **One unreadable entry is skipped.** Reading the whole booth as landed NOW
    for one bad entry would pin it in 'new' forever.
  - **A booth whose walk cannot run at all reads as NOW.** It is shown as new
    rather than hidden as old.
- **`viewed_at`**: the mtime of `.viewed`, or None.
- **`preview`**: up to 4 image items as `(url, blurred)`, first four in item
  order. A blurred one renders blurred, the same rule as the cover.
  - A booth with no images (an audio set, a report) shows today's kind
    placeholder instead (`♪ audio`, `▦ page`, `▶ video`, `◆ files`).
  - These are the original files displayed small with `loading=lazy`. No
    thumbnail is GENERATED anywhere in R2; see Out of scope.

**The index renders three sections, always in this order:**

1. **Needs you** — `marks_open > 0`, **or** `hold == "unreadable"`.
   - `marks_open` counts `open_marks(...)`, which only ever returns PICKS. A
     booth whose marks are only flags or notes is the operator's own judgment,
     not a question to them, so it is NOT here.
   - A damaged `.marks.json` holds its booth but is not open by `open_marks`
     (errored picks are not open). Somebody has to fix it, so it must not hide
     in 'everything else'. It renders with the existing "marks unreadable"
     lifetime line.
   - Ordered by `(open_since, name)`, oldest question first. A booth held
     `unreadable` has no `open_since` — even when a readable pick sits beside
     the damage, because the damage is the thing to fix — and sorts after every
     booth that has one.
2. **New since you looked** — `not in_needs_you and (viewed_at is None or
   landed_at > viewed_at)`. Ordered by `(-landed_at, name)`, newest first.
3. **Everything else** — in `list_booths`' own existing order: `(mtime, name)`
   descending, where `mtime` is today's `_newest_mtime`. That is last activity
   first, with name as the tie-break (`test_the_index_order_has_a_tie_breaker`
   pins it). The Desk reuses that rule rather than stating a second one.
   - Flagging or viewing a booth moves it up this section. That is intended:
     it is activity. It never moves the booth into (2), because (2) reads
     `landed_at` (INV-5).

The side column holds:

- **Benches**: `read_benches(data_dir)`, non-retired, in the registry's
  existing order. Its error return renders as an error line, never as an empty
  list. This is the booth page's rule: damaged and absent must not render the
  same.
- **Agent-written URLs become links only when they are `http(s)`.** A bench
  URL or a bookmark with any other scheme renders as plain text. Autoescape
  stops markup, not a `javascript:` href.
- **Bookmarks** come from the board the CLI writes: the booth named by
  `BOOTH_LINKS_BOARD`, default `links`. They are read through the same
  never-raising path as `_board_rows`, which gets factored so both callers
  share it.
  - Shown: rows that are not booth URLs (`booth_target(url) is None`).
  - Order: pinned first, then newest (`order_for_display`).
  - Capped at 8, with a link to the full board.
- **Pickup**: the existing upload form, unchanged, moved from the page head.

**An empty section does not render** — no heading, no box. This is the
load-bearing negative half of the kept-lane pair it replaces
(`'class="grid kept-grid"' not in html`), carried forward into test_flow.py as
a pair: present when it has rows, absent when it has none. It applies to each
of the three sections and to the Benches and Bookmarks panels.

The kept/ephemeral lanes are **removed**: 23 of 24 live booths are kept, so the
lanes sort nothing. Kept status and the lifetime line (`_lifetime.html`,
unchanged) remain on every row.

### C5 — the lightbox (booth.html, booth_view)

- **Layout.** Two panes on a gallery booth: the set on the left, the
  **verdict aside** on the right (`position:sticky`, `data-region="verdict"`).
  Under 1000px the aside stacks above the set, with its flags and notes
  collapsed as `<details>`, which needs no script.
  - The markup is a CLOSED `<details>`.
  - Above 1000px, CSS alone shows its content (`::details-content`) and hides
    its summary, so nothing is folded where there is room.
  - A browser without `::details-content` shows the fold at every width: one
    tap, never hidden.
- **Board booths are unchanged.** Anything with `links.md` keeps today's
  single column.
- **The aside holds, top to bottom:**
  1. open picks (the existing `_marks.html` pick rendering);
  2. the flag tray;
  3. notes;
  4. the booth-note form.
- **The flag tray is ordered by ORDINAL** — a declared change from the marks
  panel's `(created, id)`. It shows each flagged item's original file
  displayed small (no generated thumbnail), blurred if the item is blurred,
  with its #.
  The order is total with no tie-break, because rels are unique.
  - **Orphan flags** — flags whose target is no longer an item — follow the
    tray, by target, each with its unmark form. A flag the page cannot show
    must still be clearable, or it counts in the rail forever.
- **The rail stays.** Same element, same `.rail` class (booth.html's cursor
  and base.html's `--rail-h` script both read it), same filter hrefs, same
  group anchors. When `rail.groups` is non-empty AND every group is one
  contiguous run in the rendered order, the grid additionally renders an
  inline group header before each group's first tile.
  - Groups come from basenames and the order from full paths, so groups can
    interleave (`d1/aa`, `d1/bb`, `d2/aa`).
  - A header would then either repeat or file an item under the wrong group,
    so interleaved groups get no inline headers. The rail's jump links are
    unaffected. It is a
  `<div>` spanning the grid, never a `figure.item`, so the keyboard and the
  order check are blind to it by construction.
- **Every tile shows `#NN`** (its ordinal, zero-padded to the set's width).
  Each tile is `data-region="item-<url>"`, so the in-place script can replace
  exactly the tile it flagged.
- **An audio or video tile carries a `review` link** to its review page. On
  those tiles a click drives the player, so without the link the review is
  reachable only by key.

### C6 — the review (view.html, booth_view_file)

This applies to image, video and audio items. Docs keep `doc.html`.

A requested rel the filesystem cannot represent (a NUL byte, an over-long
path) is a 404, as any other unknown rel is — never a 500.

- **The stage**: the artifact at fit size, with a 1:1 toggle for images ONLY.
  - The toggle and its script are rendered and bound only when the stage is
    an `<img>`.
  - The toggle is a JS-only VIEWING convenience, as it is today: the button
    starts hidden and the script shows it. With scripts off the image shows at
    fit size, and no judgment depends on the toggle (INV-3).
  - Video and audio get their native controls and no toggle. A toggle that
    renders on audio and silently no-ops (today's script binds
    `getElementById('vimg')`) is the failure this names.
- **The rail** (`data-region="rail"`) holds:
  - the item's ordinal `#NN` (its number in the whole set, the same number
    its tile shows);
  - `K of M`, where K is its position in `review_chain` and M is the length
    of `review_chain`. The tape's "N of M seen" uses the SAME M, and N counts
    `.seen` ∩ `review_chain`;
  - its position within its group, when the review RING spans two or more
    groups (the gallery rail's own rule: one group for everything says
    nothing);
  - the caption;
  - the flag form (`back=view`);
  - notes and the add-note form (`back=view`);
  - any open pick TARGETING this item, answerable here (`back=view`);
  - the booth's other open picks as a count and a link.
- **The filmstrip** is `review_chain` in order, with ordinals, flagged frames
  underlined and the current frame in the reticle.
- **The tape** (B's device) is one segment per `review_chain` item: seen /
  flagged / current, plus "N of M seen".
- **The end of the set** is not a separate page. On the last ring item the
  rail adds a summary block: the seen count, the flag tray, and EVERY OTHER
  open pick, answerable in place.
  - That includes picks targeting other items, not only booth-level ones: the
    end of the set is where the remaining questions get cleared.
  - Before the last item, the other picks are a count and a link.
- **Keys** (additive). **Every** key here, new and old, is ignored while focus
  is in an `input`, `textarea`, `select` or `contenteditable`, the same
  `isEditable` guard view.html carries today, so F never fires mid-note:

  | key | action |
  |---|---|
  | ← → and Space | move. Shift+Space moves back. Space is left to a focused `<video>`/`<audio>` player, whose own play key it is |
  | F | flag |
  | N | focus the note |
  | Esc | back to the grid, at `#item-<url>` so the grid scrolls to where you were |

### C7 — copy and brand (the two rulings that are not layout)

- **Voice: plain and direct** (ruling `voice=plain`). Every NEW string R2
  introduces says what it means, with no villainy and no jokes. Existing
  strings are unchanged unless their surface is rewritten.
- **No SVS emblem** anywhere in the Booth's chrome (ruling `emblem=no`). The
  brand dot and the reticle favicon from the SVOS retheme stay.

## Invariants

- **INV-1 — one resolver.** `ordinal` is set in `booth_items`. No route computes
  a position.
- **INV-2 — order, stated.** Each ordered surface has a one-line rule:

  | surface | rule |
  |---|---|
  | items | `sorted(rel)` |
  | ordinals | position in that |
  | review ring | that, filtered to media |
  | filmstrip, tape | the review ring |
  | flag tray | by ordinal |
  | Desk sections | fixed: needs → new → everything |
  | needs you | `(open_since, name)` |
  | new since you looked | `(-landed_at, name)` |
  | everything else | `list_booths` order: `(mtime, name)` descending |
  | bookmarks | `order_for_display` |

  The notes list keeps `(created, id)`.
- **INV-3 — JS-off parity.** Every judgment, filter and jump works with
  scripts disabled. The only JS-only affordances are:
  - the keys;
  - the in-place swap;
  - the image 1:1 toggle (a viewing convenience, unchanged from today);
  - the existing copy buttons and blur reveal.

  The narrow-screen collapse is `<details>` and needs no script.
- **INV-4 — 303 byte-identity, for every request shape that existed before
  R2.**
  - For a request where `wants_json` is False and `back` is absent or
    `marks`, each mark route's response (status, headers, body) is
    byte-identical to its pre-R2 response.
  - `back=view` is a NEW request shape with no pre-R2 counterpart. Its landing
    is specified in C3 and is the one declared exception.
- **INV-5 — two named clocks.**
  - `mtime` / `_newest_mtime`: activity. It includes dotfiles and excludes
    locks, and it feeds lifetime and 'everything else'.
  - `landed_at`: content only (non-dot entries), and it feeds 'new since you
    looked'.
  - Never the one where the other is meant: a mark or a view is not new
    content, and new content is not the only activity.
- **INV-6 — no second renderer.** The in-place script inserts server-rendered
  HTML and builds none.
- **INV-7 — autoescape.** No `|safe` on any booth name, item name, caption,
  why or mark text. The flag tray and filmstrip render names through the same
  escaping path as the grid.
- **INV-8 — blur honesty.** A blurred item stays blurred on every new surface:
  the Desk preview strip, the flag tray, the filmstrip and the review stage.
  Reveal stays per-BROWSER and client-side (nothing persisted). Copy keeps admitting it is cosmetic.

## Assertions that change (declared before the code, per CLAUDE.md)

| test | today | after R2 | why |
|---|---|---|---|
| test_booth.py L785 | `class="grid kept-grid"` present when a booth is kept | absent; the kept booth appears in its Desk section with the `kept` lifetime line | requirement 8: the lanes sort nothing |
| test_booth.py L786 | `class="card card-kept"` present | replaced by the row carrying `data-kept="1"` | same |
| test_embed_browser.py `test_the_keyboard_flag_actually_submits` | pressing `f` causes a NAVIGATION (`page.expect_navigation()`), and the reloaded page shows the flag | pressing `f` causes NO navigation; the flag comes back from the server into the swapped tile. A window marker set before the keypress must survive, proving no reload | with JS on, the flag now applies in place (requirement 3). The gallery reload was the no-JS design working, not a defect, and the plain-form path is still pinned by the INV-4 golden. The defect R2 fixes is the full-size EJECTION, `view.html`'s flag form carrying no `back`. The test's real claim — the key reaches the server and the server's state comes back — is kept, and asserted more strictly |
| test_booth.py L789 | the kept booth renders BEFORE the ephemeral one (`html.index("links") < html.index("scratch")`) | replaced by the Desk's stated order (needs → new → everything, each with its own key) | the kept-first order was the lane's; with no lane there is no kept-first rule, and a second hidden ordering would break INV-2 |
| test_booth.py L810-811 | lane absent when nothing is kept | these two SURVIVE unchanged (they assert absence and stay true) | — |

Every other existing assertion is expected to survive, and one of the TDD
slices is "the whole suite green before any new test". Named because they were
checked:

- the `vnav vprev` / `vnav vnext` anchors (test_booth L569-591 and
  test_navigation L337) keep their classes and hrefs;
- `Wipe now` stays in the booth header;
- `class="boothhead"` stays.

## Accepted risks (named, not fixed)

- **`.seen` is read-modify-write without a lock.** Two reviews of the same
  booth racing can drop one rel from `.seen`. The cost is cosmetic — a frame
  shown unseen on the tape — and the next look repairs it; a lock would buy a
  cosmetic count at the price of a lock file the lifetime clock must ignore.
- **A `.viewed` symlink planted by an agent freezes 'new'.** `viewed_at`
  reads it by `lstat`, and `record_view` refuses to write through it
  (`O_NOFOLLOW`), so the marker never moves again: once content lands after
  it, the booth reads as 'new' however often it is opened. It fails in the
  visible direction — shown, never hidden — and needs write access to the
  booth, which already buys worse. The remedy is deleting the link.
- **`Item` gains `ordinal` with no default.** `booth_items` is the single
  construction site, keyword-only; a default would let a second site forget
  it silently (INV-1).

## Out of scope

- Compare (r3).
- Thumbnails.
- 1–9 answer keys.
- Lifetime policy for answered picks.
- The verbatim path. A verbatim booth's media items remain reachable at
  `view?f=` by URL, as today, and nothing in the verbatim page links there.
- The link-board page (`/b/links/`) beyond CSS.