petal/UX_REVIEW_2026-07-27.md

Petal UX review — 2026-07-27 (implementation doc)

Origin: a hands-on browser session against the live VPS deploy (petal.parodia.dev) on a 1517×810 desktop viewport, deliberately writing ESL-style English, accepting/undoing suggestions, using Ask Petal, the right-click dictionary, the Garden, History, and the doc-type menu. Goal: close the gap to Grammarly's feel (latency, stability, proximity of feedback) without its cost or surveillance.

How to use this doc: each item has symptom/repro, likely code location, proposed fix, and acceptance criteria. Items are ordered by value-for-effort. Where the session couldn't confirm root cause, that is said explicitly — verify before building. The product why behind Petal lives in SUGGESTIONS.md; execution phases in BUILD_PLAN.md. Nothing here contradicts them; this is polish on the existing loop.

What was verified working well (don't regress): error coverage and explanation quality across two check rounds; bilingual (en+zh) card explanations; Ask Petal follow-up answers; instant right-click dictionary with TTS + slow-replay; Garden sprouting; autosave + History snapshots; kitten cheers on accept; clean console throughout.

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0. DONE this session — kitten yields to cards

The corner mascot's halo sat on top of the bottom rail cards, History-panel footer controls, and the Garden counter, blocking reading and clicks.

Implemented (this commit): when any .petal-rail-card overlaps the mascot badge, the kitten fades to 15% opacity, shrinks 10% toward its corner (standalone scale property, so it composes with the bob animation's transform), and goes pointer-events: none so clicks pass through. It wakes (full size/opacity) while its speech bubble or the companion picker is open, or when cards no longer overlap.

• web/src/components/Companion/useCardOverlap.ts — rect-intersection hook, rAF-throttled on scroll/resize + 500 ms poll.
• web/src/components/Companion/PetalCompanion.tsx — faded wiring.
• web/src/index.css — .petal-companion-faded, transition.

Follow-up for Opus: the overlap check only watches .petal-rail-card. The History panel footer and Garden counter can still sit under the kitten. Either extend the hook's selector list (.petal-rail-card, [data-panel]…) or give those panels a bottom padding of calc(var(--petal-companion-size) * 0.5). Acceptance: with History open and with the Garden footer visible, no interactive control is under the mascot, or the mascot is faded + click-through.

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1. Bug: redo does not re-apply an accepted suggestion

Repro: accept a suggestion (text updates), press Ctrl+Z (text reverts — correct), press Ctrl+Shift+Z → nothing happens. Observed on the Idiom card "by foots → on foot".

Where to look: EditorCore.handleAccept (web/src/components/Editor/EditorCore.tsx ~line 556) applies via editor.chain().focus().insertContentAt(range, s.replacement).run(), which is a normal history transaction — so the break is probably downstream: after the undo, the parent onAccept/re-check flow may dispatch a transaction that clears the redo stack (any doc-touching tr wipes redo), or the accepted suggestion's server-side state makes the recheck rewrite content. Root cause was not confirmed in the session — instrument first.

Acceptance: accept → undo → redo restores the replacement; the suggestion card state stays consistent with whichever text is showing.

2. Suggestion stability: stop regenerating the world on every accept

The biggest feel gap vs Grammarly. Today every accept (and every edit) triggers a full-document POST /api/docs/:id/check; all remaining cards vanish and re-arrive seconds later, spans re-merge into different shapes, and the LLM re-words every explanation each round (the "weather were" card carried three different explanations in one session). It reads as instability, doubles the pause after each accept, and burns qwen3.5 tokens.

Proposed fix (server + client):

• Split the doc into sentences (or paragraphs) and hash each. On re-check, send only chunks whose hash changed since the last check; suggestions on unchanged chunks are returned from cache byte-identical, including the explanation text. internal/suggestions/handlers.go is the entry point.
• Give suggestions stable identity across checks: key on (chunk hash, original span, replacement) so an untouched suggestion keeps its id, and the client keeps the existing card DOM instead of remounting (no vanish/reappear).
• Client: on accept, remove that one card optimistically and leave the rest untouched while the changed-chunk recheck runs.

Acceptance: accepting one suggestion never changes the text, wording, or position of any other card; re-check traffic after a one-sentence edit contains only that sentence's chunk; explanations are stable across rounds.

3. Perceived latency: mask the LLM round-trip

Measured ~8–15 s from typing-stop to cards, with only a small "Checking…" in the status bar. Two independent levers, both worth doing:

• Incremental surfacing. Stream/deliver per-chunk results as each sentence finishes checking instead of one batch at the end (pairs naturally with item 2's chunking). Status bar shows a live count: "Found 3 so far…".
• Instant local rules layer. A tiny deterministic pass that underlines the classics with zero network: a/an before vowel sound, plural after some/many/three…, he/she/it + verb-s, common mass nouns ("an information"). Petal's ethos (see SUGGESTIONS.md: LLM is garnish, plain code essential) fits this exactly. Note grammarLite.test.ts already exists under web/src/components/Companion/ — check whether a rules engine is already half-built before writing a new one. Local hits render immediately with a modest style, then get confirmed/enriched (or withdrawn) when the LLM pass lands.

Acceptance: an obvious error like "a apple" underlines in <100 ms offline; during a full check, at least one card appears before the last chunk finishes; the status bar shows a running count.

4. Rail scrolls away from the text

With ~7 cards the rail is taller than the viewport; scrolling to reach lower cards scrolls the document text fully off-screen, severing the card↔sentence connection.

Proposed fix: keep the editor column sticky/pinned while the rail (web/src/components/Editor/SuggestionRail.tsx, .petal-rail in index.css) scrolls in its own overflow-y: auto container. Preserve the existing anchor-to-highlight layout for cards that fit; the container only takes over when the stack exceeds the viewport.

Acceptance: with 10+ suggestions, the flagged text stays visible while scrolling the card list; hover-linking still highlights the right span.

5. Mixed-language spans: offer translation, don't ignore

Typed mid-document: 我想说这句话但是不知道用英语怎么说。 ("I want to say this but don't know how in English") — Petal produced no card at all. The pair model (SUGGESTIONS.md §1: user may type in either language, Petal infers direction) says this should be the flagship moment.

Proposed fix: during chunking (item 2), detect spans in the pair's X language inside an English context (CJK detection already exists for spellcheck exclusion — see web/src/components/Editor/SpellCheck.ts). Emit a new suggestion type translate whose replacement is the English rendering, card labeled 翻译 · Translate, with the usual Accept / Ask Petal. Accept replaces the span (keep the original as the card's strikethrough line so she can still see what she wrote).

Acceptance: a Chinese sentence inside an English doc yields a Translate card within one check cycle; accepting swaps in the English; an English-only doc and a Chinese-only doc are unaffected.

6. Ask Petal answers: bilingual, and room to read

The card's explanation is bilingual, but the Ask Petal answer came back English-only, rendered in a small scrollable box inside the card.

Proposed fix: prompt the answer path (internal/suggestions/chat*.go / AskPetal.tsx) to reply in both pair languages (native first, mirroring the bubble pattern in PetalCompanion.tsx); let the answer area grow to the card's width with a sane max-height (~50vh) before scrolling.

Acceptance: an Ask Petal answer shows 中文 + English; a 3-paragraph answer is readable without scrolling a ~100 px box.

7. Inline popover at the underline (verify, then strengthen)

Grammarly's core gesture is click-the-word → popup at the word. EditorCore.tsx already has a hover card anchored to highlights (see handleAccept's fallback burst position), and the rail wires activeId/onHover both ways — so part of this exists. The session experience on a wide (1517 px) screen was still: click underline → the far-right rail card expands, ~400 px of eye travel.

Task: confirm the hover card appears on click as well as hover, that it offers Accept + a one-line reason + "more" (expanding the rail card), and that hover-linking (card ↔ span glow) works in both directions. Fix whichever half is missing.

Acceptance: clicking an underline shows an anchored mini-popover with Accept, without needing the rail; hovering a rail card glows its span and vice versa.

8. Smaller items (each small, do opportunistically)

• Accept All per category. Five tense fixes = five clicks today. Add "Accept all Grammar (5)" per category header in the rail, one undo step for the batch. Acceptance: batch-accept applies all, single Ctrl+Z reverts the batch.
• Keyboard flow. Tab/Shift+Tab (or n/p) cycles underlines with the popover open; Enter accepts, Esc dismisses popover. Acceptance: a doc can be fully triaged without the mouse.
• Dismissal persistence. Untested in session: does a dismissed (✕) suggestion stay dismissed after the next full re-check? With item 2's stable identity, store dismissed keys per doc and filter server-side. Acceptance: dismiss → edit elsewhere → recheck → the dismissed card does not return.
• Status-bar summary. "3 petals to polish 🌸 · 三片花瓣待打磨" next to the word count — the gentle version of Grammarly's score. No numeric grade, per the north star. Acceptance: count updates live with the rail.

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Explicit non-goals (from this review)

• No document score/grade, no streaks-pressure — the Garden and kitten already carry motivation warmly.
• No browser-extension-style everywhere-checking; Petal is the writing place.
• The doc-type dropdown's translucent look during open was animation mid-fade, not a bug — leave it.