hyperhive/docs/web-ui/terminal-rendering.md
iris adfb0f9e02 shared terminal: align row icons via a shared grid, not offsets
Per mara's screenshot report (agent-terminal icons not aligned in the
first column) — and her explicit follow-up steer on the first version of
this fix: 'dont do it by offsets at all, it should be part of the layout
that they align.'

Root cause traced first, not guessed: .row-glyph relied on inheriting
text-indent: -1.4em from .live .row to paint its glyph in the reserved
prefix slot; details.row > summary separately reset text-indent: 0 for
its own hanging-caret needs, which also zeroed the inherited value for
the icon nested inside it (indent inherits by computed value, not by
rule). Two independently-computed offsets that had to agree by hand,
and silently didn't.

Replaced the whole offset scheme with a real structural fix: every row
is a 2-column CSS grid (icon column, width from one shared
--row-icon-col custom property, then content column), and a details
row grids its own <summary> with the exact same grid-template-columns
value instead of griding itself (so its <pre> body still stacks full
width below, not squeezed into column 2). Icon and content are placed
by explicit grid-column, not auto-placement inference, so an icon-less
row's lone child still lands in the content column. .row-content is a
new wrapper class (Row.tsx, terminal.js's row()/mutableRow()/
placeholder()) giving that content an element the grid can target by
class - a DocumentFragment (what linkify() returns) doesn't persist as
a node once appended, so without an explicit wrapper there was nothing
for the grid to place.

Caught and fixed a second real bug while building this for real (not
just reasoning about the CSS): the first draft's details.row { display:
block } had lower specificity than .live .row's display: grid and never
actually applied, squeezing <summary> into the row's own 1.4em icon
column and wrapping its text one character per line. Needed
.live details.row to out-specify it.

Verified with a headless-chromium render of all 6 row shapes (flat
icon / flat icon-less / flat markdown-body / details icon / details
icon-less / a long-wrapping flat row) - all align and wrap correctly.
Also verified via the earlier Range.getBoundingClientRect() measurement
(glyph paint position, not just the element's own box): diff 0.00 for
both this and the previous fix, but only this one is structural rather
than two numbers that happen to still agree today.
2026-09-09 23:35:20 +02:00

2.9 KiB

Per-agent terminal: row taxonomy (as built)

The per-agent web UI's live pane renders one row per TermMsg (hive-agent/src/term_msg.rs): {icon?, level: debug|info|warn|error, summary, body?, body_format?: markdown|diff, coalesce_key?}. Classification (icon, summary text, whether a tool call gets an expandable body) happens server-side, once — term_msg.rs + stream_enrich.rs — and both GET /api/events/history and GET /api/events/stream serve it identically as TermEnvelope { ts, seq?, msgs: TermMsg[] } frames (hive-agent/src/web_ui/stream.rs).

The frontend renders a TermMsg close to as-is (frontend/packages/agent/src/components/Row.tsx): level picks the CSS colour (terminal.css's .live .level-*), an empty summary + markdown body renders as a flat row with just the body (assistant text), and any other bodied row is an expandable <details>, opened by default according to the operator's expand-tool-output preference (getExpandDetailsPref()) — uniformly, no per-tool override. There's no separate client-side row model or classification step.

Layout

Every row is its own 2-column grid — icon column (.row-glyph, width from the --row-icon-col custom property) then content column (.row-content, or a markdown body's own .md class) — so an icon's left edge lands in the same place regardless of row kind. A <details> row grids its <summary> instead of itself (so the <pre> body below can stack full-width), using the exact same grid-template-columns value, with the disclosure caret leading the summary text rather than the icon. One shared column definition, not two independently-computed offsets kept in sync by hand — see terminal.css's own comment on the incident that motivated the change.

Levels

Level Colour Roughly
debug muted thinking, coalesced ticks, ambient harness chatter
info default fg turn start/ok, assistant text, tool calls + results
warn amber, left rule stderr, an unrecognised event shape, API retries
error red, left rule turn failed, a tool result with is_error: true

The settings menu's "hide debug output" toggle (getHideDebugPref(), @hive/shared/prefs.js) skips debug-level rows entirely rather than muting them further — client-side only, same live-read-no-reload shape as the expand-tool-output preference above.

Per-tool icon + summary formatting (what a Read/Edit/send call's row actually says) lives in stream_enrich.rs's fmt_tool_use() family — read that when you need the specifics, this doc doesn't duplicate it.

Markdown

frontend/packages/agent/src/lib/markdown.ts's renderMarkdown() runs marked.parse() through DOMPurify into a <div class="md">. Applied to any TermMsg with body_format: "markdown".

Dashboard side (not covered here)

The main dashboard's message-flow pane is a different shape: broker messages render as .msgrow grid lines, not agent-terminal rows.