deepseek-harness/.agents/notes/implemented/feature/2026-07-21-tui-borderless-banner.md

Agent Note: The banner returns, borderless

Status: implemented

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Problem

The no-banner Agent Note removed the boxed startup banner: it deleted HeaderComponent and its sweep, moved the model into the footer, dropped the session id, and rendered welcome as the transcript's first line. The user's verdict reversed that: bring the banner back — "just remove the border". The four-row box frame was the objectionable chrome, not the identifying facts it carried (model, session id) nor the sweep-in motion.

Decision

• HeaderComponent and its left-to-right sweep return, but render borderless: no ╭─╮/╰─╯ corners and no │ side bars. Each line is a single leading space plus truncateToWidth-clipped content, so the sweep's width clip can never tear an escape sequence and no fixed frame is drawn.
• The header carries the title (DEEPSEEK HARNESS), a <model> • <session-id> detail line, and — when welcome is set — a muted subtitle. With welcome unset the header is title + detail only.
• The model also stays in the footer's left segment. The no-banner note's footer model prefix is kept, not reverted, so the driving model stays glanceable after the transient banner scrolls out of view.
• welcome reverts to a banner subtitle; the transcript-first-line notice is removed from rebuildTranscript.
• The sweep animates only when welcome is unset. A configured welcome renders the whole banner immediately, keeping fixtures and snapshots frame-deterministic. The sweep starts after ui.start() succeeds and is cleared through the same detachListeners path via stopBannerReveal, which also resets the clip so a header disposed mid-sweep re-renders whole.

This supersedes the no-banner Agent Note (which superseded the banner-sweep Agent Note): the banner and its sweep return borderless, while the model's footer home the no-banner note added stays.

Alternatives considered

Keep the box but thin it or use lighter glyphs. Rejected: the instruction was "just remove the border"; any surrounding glyph is the frame chrome the user objected to.

Drop the model from the footer now that the banner shows it again. Rejected: the banner is transient and scrolls away with the transcript, while the footer keeps the model visible for the whole session — the reason the no-banner note put it there, deliberately preserved.

Leave the session id out, as the no-banner note decided. Rejected: with the box gone the detail line costs one row, and the user asked for the banner "as before", which carried model • session-id.

Consequences

• Boot output with welcome unset is animation-dependent again (the sweep); configured welcomes stay frame-deterministic, so every snapshot and scripted fixture keeps a fixed subtitle.
• The model now appears twice at boot — banner detail and footer — intended redundancy: the banner is transient, the footer persistent.
• /clear empties the transcript but not the header, so the banner and its configured subtitle survive /clear, unlike the no-banner welcome line that /clear wiped.
• All pi-tui terminal snapshots and the examples/tui-agent replay snapshots re-recorded (test:snapshot:refresh): banner rows return with no box glyphs; footer rows keep the model prefix.
• Anything that anchored on banner absence re-anchors on its presence: the PTY smoke boots on the detail line's main-session- id (revealed late in the sweep) and asserts DEEPSEEK/HARNESS present with no box corners.

Testing

packages/ui/tui/tests/tui.spec.ts pins: the borderless banner sweeps to natural completion — no box corners, title and main-session detail present — with at least one clipped mid-sweep frame; a configured welcome renders the whole banner with no clipped frame; the unset-welcome banner has no subtitle; and dispose clears the sweep interval mid-sweep. The tui-agent and dsh-CLI PTY smokes boot on the main-session- detail marker and assert no box corners. Snapshots verify the full frames.