The composer seat is one node laid out against two different edges: in Chat it
is a sticky child of the column's scroller and rides its content box, which a
space-consuming scrollbar shortens, while a view declaring a composer overlay
gets an absolutely positioned seat against the padding box, which no bar
reduces. With the transcript scrolling the two tabs disagreed by the bar's
width, so the centred input card moved 4px sideways on every switch — and the
same 4px inside Chat when a growing transcript began to scroll.
The column now reserves its scrollbar gutter unconditionally and states the
overlay branch a scroll container on the same axes, so both states measure
against the same width.
The goal scenario asserted a paused revision-2 goal, but the pause is
appended only after cancellation reaches idle — after turn/end. Under
parallel snapshot files the subprocess could dispose before the pause
record persisted, folding the log to an active revision-1 goal.
Add a waitForEventAfterTurnEnd input step (the turn-end/title waiters'
shape, parameterized by event type) and use it in the goal scenario to
hold the subprocess open until the goal-state record lands.
The snapshot config serialized all 13 files for every mode, but the
fixture-writing rationale only holds for record (real API quota per
scenario) and refresh (write-back harvests volatile values from
fixtures on disk). Replay — the keyless default and the CI mode — is
read-only with a unique temp dir per scenario subprocess, and the
suite factory already runs replay scenarios concurrently in-file.
Narrow the serialization to non-replay modes: pnpm test:snapshot drops
from ~49s to ~33s wall; record/refresh stay fully serial.
Resuming a long session (196k events, 2.2k steps, 1.8k tool cards) took
~12s to render and ~800ms to echo one keystroke:
- Every step's timing footer called stepTimingAt, which replayed the whole
event log per footer - O(steps x events) on the initial render.
- pi-tui re-renders every component each frame and relies on per-component
line caches, but ToolCardComponent/ContextCardComponent built throwaway
Text/Markdown instances inside render(width), re-wrapping every settled
card's output on every keystroke.
Replace the per-footer replay with one shared StepTimingTracker per chat
mount (single O(events) cursor over the append-only log), and cache card
rows by width via CardLineCache, dropped by every state mutator and
invalidate().
Measured (tmux 200x50, 196k-event session): resume prompt-ready ~12s -> ~7.6s;
per-keystroke echo ~800ms median -> ~11ms.
