When a deferred tool's schema auto-loaded after the model
requested it, the resulting status toast (e.g. "Auto-loaded
deferred tool 'edit_file' after model request.") could render at
`footer_area.y - 1` — which on tight terminal layouts is the
bottom row of the composer area. The toast then visibly overwrote
the start of the user's typed text, corrupting the display until
the next redraw.
Root cause: `render_toast_stack_overlay` computed
`max_above = footer_area.y.min(full_area.height)` — bounded only
by the screen height, not by the composer's footprint. So on a
16-row terminal with composer rows 10–14 and footer at row 15,
`max_above` resolved to 15 and the renderer happily placed a
toast at row 14, on top of the composer.
The fix threads `composer_area: Rect` into the renderer and
clamps `max_above = footer_area.y.saturating_sub(composer_area.y
+ composer_area.height)`. When the composer and footer are
adjacent (no gap), `max_above` collapses to 0 and the overlay
returns early without drawing anything. Non-adjacent layouts —
which arise on taller terminals where the composer and footer
don't touch — render unchanged.
Replaced the contributor's confused test commentary with a tight
two-assertion pin: `max_above == 0` on an adjacent layout, plus a
sanity `max_above <= gap` invariant so any future regression that
re-introduces the overlap fails the test rather than the user's
display.
Harvested from PR #1485 by @MeAiRobot
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Hunter Bown
58c39ebc91