diff --git a/app/renderer/sections/Compare.test.tsx b/app/renderer/sections/Compare.test.tsx
index c547099f..edfa6641 100644
--- a/app/renderer/sections/Compare.test.tsx
+++ b/app/renderer/sections/Compare.test.tsx
@@ -3,6 +3,7 @@ import { render, screen, waitFor, within } from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
+import { __resetPolledMemo } from '../hooks/usePolled'
 import type { CohortComparisonReport, CompareJsonReport, ModelStats } from '../lib/types'
 import { Compare } from './Compare'
 
@@ -162,6 +163,21 @@ describe('Compare', () => {
     expect(mocks.getCompareModels).toHaveBeenCalledWith('30days', 'all')
   })
 
+  it('never requests the previous pair against a period whose models do not include it', async () => {
+    __resetPolledMemo()
+    const haiku = { ...modelA, model: 'Haiku 5' }
+    const gpt = { ...modelB, model: 'GPT-6' }
+    mocks.getCompareModels.mockImplementation(async period => period === 'today' ? [haiku, gpt] : [modelA, modelB])
+    mocks.getCompare.mockResolvedValue(report)
+    const { rerender } = render(<Compare period="30days" provider="all" />)
+    await waitFor(() => expect(mocks.getCompare).toHaveBeenCalledWith('30days', 'all', 'Opus 4.8', 'Sonnet 5'))
+
+    rerender(<Compare period="today" provider="all" />)
+    await waitFor(() => expect(mocks.getCompare).toHaveBeenCalledWith('today', 'all', 'Haiku 5', 'GPT-6'))
+    const stale = mocks.getCompare.mock.calls.filter(([period, , a, b]) => period === 'today' && (a === 'Opus 4.8' || b === 'Sonnet 5'))
+    expect(stale).toEqual([])
+  })
+
   it('renders the need-two-models note without requesting a report', async () => {
     mocks.getCompareModels.mockResolvedValue([modelA])
     render(<Compare period="week" provider="all" />)
@@ -334,6 +350,23 @@ describe('Compare cohorts mode', () => {
     })
   })
 
+  it('never requests the previous pair against a period whose models do not include it', async () => {
+    __resetPolledMemo()
+    const haiku = { ...modelA, model: 'Haiku 5' }
+    const gpt = { ...modelB, model: 'GPT-6' }
+    mocks.getCompareCohortModels.mockImplementation(async period =>
+      period === 'today' ? { ...facets, models: [haiku, gpt] } : facets)
+    const user = userEvent.setup()
+    const { rerender } = render(<Compare period="30days" provider="all" />)
+    await user.click(await screen.findByRole('tab', { name: 'Cohorts' }))
+    await waitFor(() => expect(mocks.getCompareCohort).toHaveBeenCalledWith('30days', 'all', 'Opus 4.8', 'Sonnet 5', undefined, undefined, undefined))
+
+    rerender(<Compare period="today" provider="all" />)
+    await waitFor(() => expect(mocks.getCompareCohort).toHaveBeenCalledWith('today', 'all', 'Haiku 5', 'GPT-6', undefined, undefined, undefined))
+    const stale = mocks.getCompareCohort.mock.calls.filter(([period, , a, b]) => period === 'today' && (a === 'Opus 4.8' || b === 'Sonnet 5'))
+    expect(stale).toEqual([])
+  })
+
   it('returns to the classic comparison unchanged', async () => {
     const user = await openCohorts()
     mocks.getCompareModels.mockResolvedValue([modelA, modelB])
diff --git a/app/renderer/sections/Compare.tsx b/app/renderer/sections/Compare.tsx
index 22b6e9bb..28d41475 100644
--- a/app/renderer/sections/Compare.tsx
+++ b/app/renderer/sections/Compare.tsx
@@ -194,7 +194,7 @@ function ClassicCompare({
           }}
         />
       </div>
-      {modelA && modelB && modelA !== modelB && (
+      {modelA && modelB && modelA !== modelB && modelRows.some(row => row.model === modelA) && modelRows.some(row => row.model === modelB) && (
         <CompareReport
           period={period}
           provider={provider}
@@ -432,11 +432,15 @@ function CohortCompare({
     })
   }, [facets.data])
 
+  // facets.data is masked to the current period/provider, so this keeps the
+  // previous selection from being requested before the effect above resets it
+  // (the CLI exits 1 on a model it cannot find).
+  const listed = (model: string | null) => !!model && !!facets.data?.models.some(row => row.model === model)
   const report = usePolled<CohortComparisonReport>(
     () => codeburn.getCompareCohort(period, provider, modelA ?? '', modelB ?? '', range ?? undefined, project ? [project] : undefined, category || undefined),
     [period, provider, modelA, modelB, range?.from, range?.to, project, category, refreshToken],
     {
-      enabled: ready && !!modelA && !!modelB && modelA !== modelB,
+      enabled: ready && listed(modelA) && listed(modelB) && modelA !== modelB,
       memoKey: reportMemoKey('cohort-v2', period, provider, range, JSON.stringify([modelA, modelB, project, category])),
     },
   )