Tianyi Cui
4.3 KiB
Agent Note: Web message IconActions and clocks
Status: implemented
English | 中文
Problem
The web chat user bubble already had copy / branch / edit IconActions but no clock. Finalized assistant narration had no under-body action chrome at all, even though the Harness design shows a copy / branch / clock row after the answer settles. Streaming replies must not flash that chrome mid-token. Memoized rows also keep stable props across midnight, so a one-shot Date.now() would leave yesterday's messages stuck on HH:mm.
Decision
User bubbles prepend a date-aware local clock to the existing IconActions row; the last content-text assistant of each turn appends a copy / branch / clock row with margin-top: 16px; both seats stay visible whenever mounted and re-format at the next local midnight.
Both seats format node.time through formatMessageClock: same calendar day → HH:mm, earlier this year → M月D日 HH:mm, other years → YYYY年M月D日 HH:mm. useCalendarDay is a component-local day tick (timeout to the next local midnight) so memoized rows re-render when the calendar day changes without a new framework hook. MessageItem places the label before copy (figma 388:20051). ChatView derives turn-tail seqs via assistantActionsSeqs and withholds time for mid-turn content; AssistantMarkdown places the row after branch (figma 43:32997) only when streaming is false, the event time is known, and the node has non-empty text content. Think-only nodes, mid-turn narration, and the streaming tail omit the row. Copy writes joined text blocks. Both message rows pass their event's seq to the same fork callback; Web session fork actions define the real mutation contract. Clipboard write and the clock helpers live in message-chrome.ts. The assembled surface is pinned by apps/web/tests/message-actions.e2e.ts (cold-seeded history + aria golden); aria normalization collapses every clock shape to {{clock}}.
Alternatives considered
Show assistant IconActions during streaming. Rejected: the request is to reveal the row only after output completes; mid-stream chrome would flicker and invite copying a partial answer.
Put IconActions under every finalized assistant node (including Think-only). Rejected: copy has nothing useful to write without text content, and repeating the chrome under every step/Think row clutters the flow; only content output owns the seat.
Put IconActions under every content-text assistant in a multi-step turn. Rejected: mid-turn narration (text before tools) is not the settled answer; repeating copy/branch/clock under each step clutters the flow. Only the last content assistant of the turn owns the seat.
Hover-reveal the action row on hover-capable pointers. Rejected: once the row exists it should stay discoverable; opacity hiding made the chrome easy to miss and required parent hover selectors that duplicated the mount gate.
Let the IconActions decision also define session fork semantics. Rejected: this note owns only message chrome, clocks, and mount gating; boundary selection, failure behavior, and switching semantics belong to the separate Web session fork actions, keeping presentation components from becoming a second home for session mutation.
Publish the calendar day through a chat store or inject hook. Rejected: the day tick is presentation-only local state with no cross-entry consumers; a component-local timeout matches the client rule that behavioral hooks may own state that does not subscribe to an external source.
Consequences
Each turn's last settled content answer exposes copy, branch, and the event clock as soon as the row mounts; mid-turn content and Think-only nodes stay chrome-free. User and assistant clocks share the same day/year widening rules and refresh after midnight without a message mutation. Per-message paging remains a deferred footer seat in the package README. Package tests pin the three clock shapes, the midnight widen, the content-only assistant gate, the turn-tail seq gate, and the respective event seq values passed by the user and assistant branch buttons; the web e2e scenario pins the assembled IconActions chrome.