fix(terminal): remove scrollback demotion (C1 slice C)

The scrollback demotion feature for eviction-exempt hidden worktrees is no longer needed. Retention budget limits are now sufficient without this additional bound. Remove the terminal-hidden-scrollback-demotion module, the selectScrollbackDemotedTerminalWorktrees function, and related per-pane demotion logic.

src/renderer/src/components/Terminal.tsx

@@ -94,13 +94,8 @@ import {
 import {
   TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS,
   selectRetentionForceParkedTerminalWorktrees,
-  selectScrollbackDemotedTerminalWorktrees,
   type TerminalWorktreeRetentionCandidate
 } from './terminal-pane/terminal-hidden-worktree-retention'
-import {
-  resetTerminalScrollbackDemotion,
-  setScrollbackDemotedTerminalWorktrees
-} from './terminal-pane/terminal-hidden-scrollback-demotion'
 import { captureTerminalShutdownBuffersBestEffort } from './terminal-pane/shutdown-buffer-captures'
 import { getTerminalParkingPolicyOverrides } from './terminal-pane/terminal-parking-e2e-overrides'
 import { useColdParkedTerminalPresentation } from './terminal-pane/use-cold-parked-terminal-presentation'
@@ -302,9 +297,6 @@ function Terminal(): React.JSX.Element | null {
   const terminalRetentionBudgetEnabled = useAppStore(
     (s) => s.settings?.terminalHiddenWorktreeRetentionBudget !== false
   )
-  const terminalScrollbackDemotionEnabled = useAppStore(
-    (s) => s.settings?.terminalHiddenScrollbackDemotion !== false
-  )
   const terminalTitleSnapshotAuthorityEnabled = useAppStore((s) =>
     isMainTerminalSideEffectAuthorityForPty({
       settings: s.settings,
@@ -1072,18 +1064,6 @@ function Terminal(): React.JSX.Element | null {
     setForceParkedTerminalWorktreeIds((current) =>
       haveSameWorktreeIds(current, forceParkedWorktreeIds) ? current : forceParkedWorktreeIds
     )
-    // C1 slice C: eviction-exempt worktrees stay mounted, so past the TTL their
-    // hidden panes demote to the minimum scrollback tier instead of unmounting.
-    setScrollbackDemotedTerminalWorktrees(
-      selectScrollbackDemotedTerminalWorktrees({
-        worktrees: retentionBudgetCandidates,
-        parkingEnabled: terminalParkingEnabled,
-        retentionBudgetEnabled: terminalRetentionBudgetEnabled,
-        demotionEnabled: terminalScrollbackDemotionEnabled,
-        nowMs,
-        ...overrides
-      })
-    )
     const retentionTtlEligibleIds = new Set(
       retentionBudgetCandidates
         .filter((candidate) => !candidate.ordinaryParkingCovers && !candidate.hasPendingSpawnWork)
@@ -1105,10 +1085,8 @@ function Terminal(): React.JSX.Element | null {
         parkCooldownUntilMs: candidate.parkCooldownUntilMs,
         nowMs,
         ...overrides,
-        // Why: only retention candidates wake at the eviction TTL; everyone else keeps the ordinary
-        // deadlines. Demotion (slice C) needs the wakeup too — it no longer requires slice B's switch.
-        ...((terminalRetentionBudgetEnabled || terminalScrollbackDemotionEnabled) &&
-        retentionTtlEligibleIds.has(candidate.worktreeId)
+        // Why: only retention candidates wake at the eviction TTL; everyone else keeps the ordinary deadlines.
+        ...(terminalRetentionBudgetEnabled && retentionTtlEligibleIds.has(candidate.worktreeId)
           ? {
               retentionTtlMs: overrides.retentionTtlMs ?? TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS
             }
@@ -1133,7 +1111,6 @@ function Terminal(): React.JSX.Element | null {
     terminalParkingEnabled,
     terminalParkingRevision,
     terminalRetentionBudgetEnabled,
-    terminalScrollbackDemotionEnabled,
     terminalSshParkingEnabled,
     workspaceSurfaces
   ])
@@ -1373,14 +1350,8 @@ function Terminal(): React.JSX.Element | null {
     workspaceSessionReady,
     workspaceSurfaces
   ])
-  // Why: on host unmount no reconciliation effect runs again, so dispose every remaining parked watcher and drop the demotion verdicts nothing would recompute.
-  useEffect(
-    () => () => {
-      disposeAllParkedTerminalWatchers()
-      resetTerminalScrollbackDemotion()
-    },
-    []
-  )
+  // Why: on host unmount no reconciliation effect runs again, so dispose every remaining parked watcher.
+  useEffect(() => () => disposeAllParkedTerminalWatchers(), [])
   // Auto-create first tab when worktree activates
   useEffect(() => {
     if (!workspaceSessionReady) {

src/renderer/src/components/terminal-pane/terminal-hidden-scrollback-demotion.test.ts

@@ -1,71 +0,0 @@
-import { afterEach, describe, expect, it, vi } from 'vitest'
-import {
-  TERMINAL_DEMOTED_SCROLLBACK_ROWS,
-  demotedTerminalScrollbackRows,
-  isTerminalWorktreeScrollbackDemoted,
-  resetTerminalScrollbackDemotion,
-  resolveTerminalMountScrollbackRows,
-  setScrollbackDemotedTerminalWorktrees,
-  subscribeTerminalScrollbackDemotion
-} from './terminal-hidden-scrollback-demotion'
-
-afterEach(() => {
-  setScrollbackDemotedTerminalWorktrees(new Set())
-})
-
-describe('setScrollbackDemotedTerminalWorktrees', () => {
-  it('replaces the demoted set', () => {
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-1', 'wt-2']))
-    expect(isTerminalWorktreeScrollbackDemoted('wt-1')).toBe(true)
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-2']))
-    expect(isTerminalWorktreeScrollbackDemoted('wt-1')).toBe(false)
-    expect(isTerminalWorktreeScrollbackDemoted('wt-2')).toBe(true)
-  })
-
-  it('does not notify when the set content is unchanged (flip-loop damping)', () => {
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-1']))
-    const listener = vi.fn()
-    const unsubscribe = subscribeTerminalScrollbackDemotion(listener)
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-1']))
-    expect(listener).not.toHaveBeenCalled()
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-1', 'wt-2']))
-    expect(listener).toHaveBeenCalledTimes(1)
-    unsubscribe()
-  })
-})
-
-describe('resetTerminalScrollbackDemotion', () => {
-  // Why: module state outlives the host, so a stale verdict would demote a pane
-  // that remounts before any effect recomputes it.
-  it('clears every verdict and notifies subscribers', () => {
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-1', 'wt-2']))
-    const listener = vi.fn()
-    const unsubscribe = subscribeTerminalScrollbackDemotion(listener)
-    resetTerminalScrollbackDemotion()
-    expect(isTerminalWorktreeScrollbackDemoted('wt-1')).toBe(false)
-    expect(isTerminalWorktreeScrollbackDemoted('wt-2')).toBe(false)
-    expect(listener).toHaveBeenCalledTimes(1)
-    unsubscribe()
-  })
-})
-
-describe('demotedTerminalScrollbackRows', () => {
-  it('never exceeds the configured rows', () => {
-    expect(demotedTerminalScrollbackRows(50_000)).toBe(TERMINAL_DEMOTED_SCROLLBACK_ROWS)
-    expect(demotedTerminalScrollbackRows(500)).toBe(500)
-  })
-})
-
-describe('resolveTerminalMountScrollbackRows', () => {
-  // Why: pane births (splits) under an already-demoted worktree bypass the
-  // post-mount demotion effect entirely — the mount options must demote.
-  it('demotes new xterms while the worktree verdict is set, restores after clear', () => {
-    setScrollbackDemotedTerminalWorktrees(new Set(['wt-demoted']))
-    expect(resolveTerminalMountScrollbackRows('wt-demoted', 50_000)).toBe(
-      TERMINAL_DEMOTED_SCROLLBACK_ROWS
-    )
-    expect(resolveTerminalMountScrollbackRows('wt-other', 50_000)).toBe(50_000)
-    resetTerminalScrollbackDemotion()
-    expect(resolveTerminalMountScrollbackRows('wt-demoted', 50_000)).toBe(50_000)
-  })
-})

src/renderer/src/components/terminal-pane/terminal-hidden-scrollback-demotion.ts

@@ -1,72 +0,0 @@
-import { useSyncExternalStore } from 'react'
-import { DESKTOP_TERMINAL_SCROLLBACK_ROWS_MIN } from '../../../../shared/terminal-scrollback-policy'
-
-/** Demoted hidden panes keep the minimum retention tier (~1.3MB V8 heap vs
- *  ~19MB at 50k rows, measured); trimmed history is gone by design — reveal
- *  restores the configured cap for future output only. */
-export const TERMINAL_DEMOTED_SCROLLBACK_ROWS = DESKTOP_TERMINAL_SCROLLBACK_ROWS_MIN
-
-// Why module state (same pattern as parked watchers): the verdict is computed
-// in Terminal.tsx but applied by each mounted pane's lifecycle hook — prop
-// threading would cross three component layers for a per-worktree boolean.
-const demotedWorktreeIds = new Set<string>()
-const listeners = new Set<() => void>()
-
-export function setScrollbackDemotedTerminalWorktrees(next: ReadonlySet<string>): void {
-  if (
-    next.size === demotedWorktreeIds.size &&
-    [...next].every((id) => demotedWorktreeIds.has(id))
-  ) {
-    return
-  }
-  demotedWorktreeIds.clear()
-  for (const id of next) {
-    demotedWorktreeIds.add(id)
-  }
-  for (const listener of listeners) {
-    listener()
-  }
-}
-
-/**
- * Clear every verdict — the demotion host is gone, so nothing recomputes them.
- * Without this a pane remounting later reads a stale demotion (React runs the
- * pane's scrollback effect BEFORE the host effect that would clear it) and
- * xterm trims its restore replay to 1 000 rows, unrecoverably.
- */
-export function resetTerminalScrollbackDemotion(): void {
-  setScrollbackDemotedTerminalWorktrees(new Set())
-}
-
-export function isTerminalWorktreeScrollbackDemoted(worktreeId: string): boolean {
-  return demotedWorktreeIds.has(worktreeId)
-}
-
-export function subscribeTerminalScrollbackDemotion(listener: () => void): () => void {
-  listeners.add(listener)
-  return () => listeners.delete(listener)
-}
-
-/** Live per-worktree demotion verdict for a mounted pane host. */
-export function useTerminalWorktreeScrollbackDemoted(worktreeId: string): boolean {
-  return useSyncExternalStore(subscribeTerminalScrollbackDemotion, () =>
-    demotedWorktreeIds.has(worktreeId)
-  )
-}
-
-export function demotedTerminalScrollbackRows(configuredRows: number): number {
-  return Math.min(TERMINAL_DEMOTED_SCROLLBACK_ROWS, configuredRows)
-}
-
-/** Scrollback for a NEW xterm in this worktree. Pane births under an
- *  already-demoted worktree (splits, layout replays) must take the demoted
- *  tier at create — the post-mount demotion effect only re-runs when the
- *  verdict or setting flips, so it never covers them. */
-export function resolveTerminalMountScrollbackRows(
-  worktreeId: string,
-  configuredRows: number
-): number {
-  return demotedWorktreeIds.has(worktreeId)
-    ? demotedTerminalScrollbackRows(configuredRows)
-    : configuredRows
-}

src/renderer/src/components/terminal-pane/terminal-hidden-worktree-retention.test.ts

@@ -4,7 +4,6 @@ import {
   TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS,
   isEvictionExemptTerminalPty,
   selectRetentionForceParkedTerminalWorktrees,
-  selectScrollbackDemotedTerminalWorktrees,
   type TerminalWorktreeRetentionCandidate
 } from './terminal-hidden-worktree-retention'
 
@@ -175,157 +174,3 @@ describe('selectRetentionForceParkedTerminalWorktrees', () => {
     }
   })
 })
-
-describe('selectScrollbackDemotedTerminalWorktrees', () => {
-  const nowMs = 5_000_000
-  const aged = nowMs - TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS
-  const base = {
-    parkingEnabled: true,
-    retentionBudgetEnabled: true,
-    demotionEnabled: true,
-    nowMs
-  }
-
-  function exemptCandidate(
-    worktreeId: string,
-    hiddenSinceMs: number | null,
-    partial: Partial<TerminalWorktreeRetentionCandidate> = {}
-  ): TerminalWorktreeRetentionCandidate {
-    return {
-      worktreeId,
-      hiddenSinceMs,
-      isVisible: false,
-      shouldMeasureHiddenWorktree: false,
-      hasActivityTerminalPortal: false,
-      ordinaryParkingCovers: false,
-      hasEvictionExemptTab: true,
-      hasPendingSpawnWork: false,
-      ...partial
-    }
-  }
-
-  it('demotes only eviction-exempt worktrees hidden past the TTL', () => {
-    const selected = selectScrollbackDemotedTerminalWorktrees({
-      ...base,
-      worktrees: [
-        exemptCandidate('wt-aged', aged),
-        exemptCandidate('wt-recent', nowMs - 60_000),
-        exemptCandidate('wt-not-exempt', aged, { hasEvictionExemptTab: false }),
-        exemptCandidate('wt-visible', aged, { isVisible: true }),
-        exemptCandidate('wt-portal', aged, { hasActivityTerminalPortal: true }),
-        exemptCandidate('wt-pending', aged, { hasPendingSpawnWork: true }),
-        exemptCandidate('wt-unhidden', null)
-      ]
-    })
-    expect(selected).toEqual(new Set(['wt-aged']))
-  })
-
-  it('returns empty when the master or demotion switch is off', () => {
-    const worktrees = [exemptCandidate('wt-aged', aged)]
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, parkingEnabled: false })
-    ).toEqual(new Set())
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, demotionEnabled: false })
-    ).toEqual(new Set())
-  })
-
-  it('demotes independently of the slice-B retention-budget switch', () => {
-    const worktrees = [exemptCandidate('wt-aged', aged)]
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({
-        ...base,
-        worktrees,
-        retentionBudgetEnabled: false
-      })
-    ).toEqual(new Set(['wt-aged']))
-  })
-
-  it('demotes an exempt worktree as soon as it force-parks under the count budget, before the TTL', () => {
-    // Why: after a force-park the exempt tabs' panes are the only ones left
-    // mounted in that worktree, so they take the demoted scrollback tier.
-    const underTtl = nowMs - TERMINAL_WORKTREE_PARK_DELAY_MS
-    const worktrees = [
-      exemptCandidate('wt-a', underTtl - 3),
-      exemptCandidate('wt-b', underTtl - 2),
-      exemptCandidate('wt-c', underTtl - 1),
-      exemptCandidate('wt-d', underTtl)
-    ]
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, retentionLimit: 2 })
-    ).toEqual(new Set(['wt-a', 'wt-b']))
-  })
-
-  it('demotes un-parkable non-exempt worktrees the force-park lever spared, past the TTL', () => {
-    // wt-solo is the only candidate → last-active exempt from force-park; its
-    // panes stay fully mounted forever unless demotion bounds them.
-    const solo = [exemptCandidate('wt-solo', aged, { hasEvictionExemptTab: false })]
-    expect(selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees: solo })).toEqual(
-      new Set(['wt-solo'])
-    )
-    // With slice B off nothing force-parks; every un-parkable worktree past
-    // the TTL demotes (C bounds independently).
-    const pair = [
-      exemptCandidate('wt-a', aged - 1, { hasEvictionExemptTab: false }),
-      exemptCandidate('wt-b', aged, { hasEvictionExemptTab: false })
-    ]
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({
-        ...base,
-        worktrees: pair,
-        retentionBudgetEnabled: false
-      })
-    ).toEqual(new Set(['wt-a', 'wt-b']))
-    // With slice B on, wt-a force-parks (unmounted — no demotion needed) and
-    // only the spared last-active wt-b demotes.
-    expect(selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees: pair })).toEqual(
-      new Set(['wt-b'])
-    )
-    // Ordinary-parking-covered worktrees are bounded by the warm cap already.
-    const covered = [
-      exemptCandidate('wt-covered', aged, {
-        hasEvictionExemptTab: false,
-        ordinaryParkingCovers: true
-      })
-    ]
-    expect(selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees: covered })).toEqual(
-      new Set()
-    )
-  })
-
-  it('is idempotent and only grows as time advances (flip-loop dwell)', () => {
-    const worktrees = [
-      exemptCandidate('wt-exempt', aged),
-      exemptCandidate('wt-force-parked', aged, { hasEvictionExemptTab: false }),
-      exemptCandidate('wt-last-active', nowMs - 60_000, { hasEvictionExemptTab: false })
-    ]
-    const first = selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees })
-    expect(selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees })).toEqual(first)
-    // Why: with unchanged inputs, a later evaluation may only ADD members —
-    // a verdict that oscillates with time is the React-#185 ingredient.
-    for (const laterMs of [nowMs + 1_000, nowMs + TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS]) {
-      const later = selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, nowMs: laterMs })
-      for (const id of first) {
-        expect(later.has(id)).toBe(true)
-      }
-    }
-  })
-
-  it('honors the retentionTtlMs override and stays time-monotone', () => {
-    const worktrees = [exemptCandidate('wt-1', nowMs - 500)]
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, retentionTtlMs: 400 })
-    ).toEqual(new Set(['wt-1']))
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({ ...base, worktrees, retentionTtlMs: 600 })
-    ).toEqual(new Set())
-    expect(
-      selectScrollbackDemotedTerminalWorktrees({
-        ...base,
-        worktrees,
-        retentionTtlMs: 600,
-        nowMs: nowMs + 200
-      })
-    ).toEqual(new Set(['wt-1']))
-  })
-})

src/renderer/src/components/terminal-pane/terminal-hidden-worktree-retention.ts

@@ -20,10 +20,10 @@ export const TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS = 45 * 60_000
 // Why: an eviction-exempt pty is a live local one a remount could not reattach
 // (daemon-fail-open separator-less ids, ptys minted under another worktree) — a
 // fresh spawn would orphan the live shell. Its TAB keeps its mounted pane when
-// the worktree force-parks (per-tab exclusion, mirroring Activity portals) and
-// relies on scrollback demotion instead. Per-PTY, not per-tab: the coverage
-// veto that makes a worktree a retention candidate walks every split pane, so
-// the exemption must too (see isEvictionExemptTerminalTab).
+// the worktree force-parks (per-tab exclusion, mirroring Activity portals).
+// Per-PTY, not per-tab: the coverage veto that makes a worktree a retention
+// candidate walks every split pane, so the exemption must too (see
+// isEvictionExemptTerminalTab).
 export function isEvictionExemptTerminalPty(
   ptyId: string | null | undefined,
   worktreeId: string
@@ -98,66 +98,3 @@ export function selectRetentionForceParkedTerminalWorktrees(
     hotRetainLimit: args.retentionLimit ?? TERMINAL_HIDDEN_WORKTREE_RETENTION_LIMIT
   })
 }
-
-/**
- * Scrollback demotion targets the hidden panes that stay mounted past the
- * retention deadlines: (a) eviction-exempt tabs' worktrees (their panes
- * survive force-park via the per-tab exclusion) demote past the TTL — or
- * immediately when their worktree force-parks under the count budget, since
- * the exempt panes are then the only ones left mounted; (b) un-parkable
- * worktrees the force-park lever spared (the last-active exemption, or slice
- * B switched off) demote past the TTL instead of holding full scrollback
- * forever. Time-monotone for fixed inputs: the force-parked and past-TTL sets
- * only ever grow with nowMs and the last-active pick is time-independent, so
- * membership only grows until a reveal resets hiddenSince — no oscillation
- * surface.
- *
- * Demotion is WORKTREE-scoped by design: one eviction-exempt leaf demotes
- * every still-mounted pane in the worktree, including parkable siblings a
- * mixed split tab keeps mounted (exemption is tab-granular). Coarser than
- * per-pane, deliberately — do not "fix" to per-pane demotion without
- * revisiting the retention-budget contract in the C1 PR body.
- */
-export function selectScrollbackDemotedTerminalWorktrees(
-  args: {
-    worktrees: readonly TerminalWorktreeRetentionCandidate[]
-    parkingEnabled: boolean
-    retentionBudgetEnabled: boolean
-    demotionEnabled: boolean
-    nowMs: number
-  } & TerminalColdParkPolicyOverrides
-): Set<string> {
-  // Why parkingEnabled still gates: it is the master kill switch — parking
-  // globally off means nothing parks OR demotes. Slice B's budget switch does
-  // not gate slice C; each slice reverts independently (approved contract).
-  if (!args.parkingEnabled || !args.demotionEnabled) {
-    return new Set()
-  }
-  const ttlMs = args.retentionTtlMs ?? TERMINAL_HIDDEN_WORKTREE_RETENTION_TTL_MS
-  const forceParked = selectRetentionForceParkedTerminalWorktrees(args)
-  const demoted = new Set<string>()
-  for (const worktree of args.worktrees) {
-    if (
-      worktree.hiddenSinceMs === null ||
-      worktree.isVisible ||
-      worktree.shouldMeasureHiddenWorktree ||
-      worktree.hasActivityTerminalPortal ||
-      worktree.hasPendingSpawnWork
-    ) {
-      continue
-    }
-    const pastTtl = args.nowMs - worktree.hiddenSinceMs >= ttlMs
-    if (worktree.hasEvictionExemptTab) {
-      if (pastTtl || forceParked.has(worktree.worktreeId)) {
-        demoted.add(worktree.worktreeId)
-      }
-      continue
-    }
-    // Force-park candidates the lever spared stay fully mounted, so demotion
-    // is their only bound; force-parked ones already unmounted.
-    if (!worktree.ordinaryParkingCovers && pastTtl && !forceParked.has(worktree.worktreeId)) {
-      demoted.add(worktree.worktreeId)
-    }
-  }
-  return demoted
-}

src/renderer/src/components/terminal-pane/use-terminal-pane-lifecycle.ts

@@ -15,11 +15,6 @@ import {
   resolveTerminalCursorInactiveStyle
 } from '@/lib/pane-manager/pane-terminal-options'
 import { normalizeDesktopTerminalScrollbackRows } from '../../../../shared/terminal-scrollback-policy'
-import {
-  demotedTerminalScrollbackRows,
-  resolveTerminalMountScrollbackRows,
-  useTerminalWorktreeScrollbackDemoted
-} from './terminal-hidden-scrollback-demotion'
 import {
   configureTerminalOutputBacklogCap,
   writeTerminalOutput
@@ -574,8 +569,6 @@ export function useTerminalPaneLifecycle({
   const terminalScrollbackRows = normalizeDesktopTerminalScrollbackRows(
     settings?.terminalScrollbackRows
   )
-  // C1 slice C: hidden eviction-exempt worktrees drop to the minimum scrollback tier past the retention TTL.
-  const scrollbackDemoted = useTerminalWorktreeScrollbackDemoted(worktreeId)
   // Why here: backlog cap scales with the scrollback setting; set it where the setting is read to stay in lockstep.
   configureTerminalOutputBacklogCap(settings?.terminalScrollbackRows)
   const systemPrefersDarkRef = useRef(systemPrefersDark)
@@ -1334,12 +1327,8 @@ export function useTerminalPaneLifecycle({
           fontFamily: buildFontFamily(currentSettings?.terminalFontFamily ?? ''),
           fontWeight: terminalFontWeights.fontWeight,
           fontWeightBold: terminalFontWeights.fontWeightBold,
-          // Why resolveTerminalMountScrollbackRows: pane births while the
-          // worktree is already demoted (C1 slice C) must not resurrect the
-          // full tier — the post-mount demotion effect doesn't re-run for them.
-          scrollback: resolveTerminalMountScrollbackRows(
-            worktreeId,
-            normalizeDesktopTerminalScrollbackRows(currentSettings?.terminalScrollbackRows)
+          scrollback: normalizeDesktopTerminalScrollbackRows(
+            currentSettings?.terminalScrollbackRows
           ),
           cursorStyle,
           cursorInactiveStyle: resolveTerminalCursorInactiveStyle(cursorStyle),
@@ -1768,13 +1757,8 @@ export function useTerminalPaneLifecycle({
       return
     }
     // Why: live row-retention changes are xterm option updates only — must not recreate/replay/refit/resize/signal the PTY.
-    applyTerminalScrollbackRowsToMountedPanes(
-      manager,
-      scrollbackDemoted
-        ? demotedTerminalScrollbackRows(terminalScrollbackRows)
-        : terminalScrollbackRows
-    )
-  }, [managerRef, scrollbackDemoted, terminalScrollbackRows])
+    applyTerminalScrollbackRowsToMountedPanes(manager, terminalScrollbackRows)
+  }, [managerRef, terminalScrollbackRows])
 
   useEffect(() => {
     const manager = managerRef.current

src/shared/constants.ts

@@ -304,7 +304,6 @@ export function getDefaultSettings(homedir: string): GlobalSettings {
     // settings objects (which omit them) keep the default-on behavior.
     terminalSshViewParking: true,
     terminalHiddenWorktreeRetentionBudget: true,
-    terminalHiddenScrollbackDemotion: true,
     terminalMainSideEffectAuthority: true,
     terminalHiddenDeliveryGate: true,
     terminalModelQueryAuthority: true,

src/shared/types.ts

@@ -2852,8 +2852,6 @@ export type GlobalSettings = {
   terminalSshViewParking?: boolean
   /** Kill switch for the hidden-worktree retention budget (C1): force-parks the least-recently-hidden un-parkable worktrees beyond a count budget or TTL. */
   terminalHiddenWorktreeRetentionBudget?: boolean
-  /** Kill switch for scrollback demotion (C1): eviction-exempt hidden worktrees drop to the minimum scrollback tier past the retention TTL. */
-  terminalHiddenScrollbackDemotion?: boolean
   /** Kill switch for main-process PTY side-effect authority; on (default) = title/bell/agent facts via pty:sideEffect channel, not renderer byte parsing. */
   terminalMainSideEffectAuthority?: boolean
   /** Kill switch for main's hidden-delivery gate (Phase 4): drops PTY bytes to hidden views after model ingestion; requires terminalMainSideEffectAuthority. */