EventController.handleEvent rebuilt the editor's status-line top border
synchronously on every session event via updateEditorTopBorder(). During
a long-running eval that fires 5-10 events/s, each rebuild ran
StatusLine.getTopBorder → #buildSegmentContext → getCachedContextBreakdown
→ session.getContextUsage → estimateTokens (with JSON.stringify per
toolCall block) — the render pipeline is throttled to ~30 fps, so most
rebuilds were dropped before painting. Combined with a scheduler that
collapsed cadenceDelay to zero whenever a frame overran the 33ms budget,
the TUI busy-looped at ~40-50% CPU.
Fix:
- Editor gains setTopBorderProvider(): a lazy builder invoked once per
editor render. InteractiveMode installs it in the constructor and on
setEditorComponent, so the rebuild coalesces to the render tempo
regardless of event rate.
- Delete updateEditorTopBorder wrapper (now equivalent to
ui.requestRender) and inline every call site.
- Add adaptive render backpressure: a frame that exceeds
MIN_RENDER_INTERVAL_MS inflates the next scheduling delay to
2 * last_frame_cost, capped at 200 ms, targeting a 50% render duty
cycle instead of pinning the CPU at t=0.
New regression tests:
- editor-top-border-provider.test.ts: provider fires exactly once per
render, wins over eager setTopBorder, falls back when cleared, gets
the correct availableWidth.
- adaptive-render-backpressure.test.ts: cheap frames keep the 33 ms
cadence, a slow frame idles proportionally, pathological frames are
capped at 200 ms.
Verified with bun test packages/tui/test (all 246 relevant tests pass)
and bun test packages/coding-agent/test/modes (455 tests pass). Three
pre-existing agent-session-handoff snapcompact failures on main are
unrelated (snapcompactSupportedChars binding).
Fixes#4145
Add provider-native V2 remote compaction metadata to discovered OpenAI Codex models so context-full compaction uses the streaming compaction_trigger path instead of the legacy compact endpoint.
Expose the V2 remote compaction schema fields in models.yml and cover the Codex discovery metadata contract.
Fixes#4146
Bun on macOS 15+ (Darwin 24/25) returns the literal string "unknown" from
os.version() when uv_os_uname() cannot populate the version field. That
value was piped straight into the <workstation> block as `Kernel:
unknown`, and the model then guessed the OS glyph from the ambiguous
signal — displaying a Windows logo on Macs.
Fall back to `${os.type()} ${os.release()}` (uname -s + uname -r, e.g.
`Darwin 25.5.0`) whenever os.version() is empty or the literal
"unknown". Linux keeps its build string when Bun returns one.
Fixes#4141
can1357