diff --git a/.github/workflows/test-iseberg.yml b/.github/workflows/test-iseberg.yml
index dc33dde..79c8d10 100644
--- a/.github/workflows/test-iseberg.yml
+++ b/.github/workflows/test-iseberg.yml
@@ -15,6 +15,7 @@ on:
       - "NuGet.Config"
       - "global.json"
       - "scripts/Install-IsebergTestPowerShell.ps1"
+      - "scripts/Test-IsebergCore.ps1"
   pull_request:
     paths:
       - ".github/workflows/test-iseberg.yml"
@@ -27,6 +28,7 @@ on:
       - "NuGet.Config"
       - "global.json"
       - "scripts/Install-IsebergTestPowerShell.ps1"
+      - "scripts/Test-IsebergCore.ps1"
   schedule:
     - cron: "0 6 * * 1"
   workflow_dispatch:
@@ -70,24 +72,10 @@ jobs:
         shell: pwsh
         run: ./scripts/Install-IsebergTestPowerShell.ps1
 
-      - name: Test engine, workbench, and settings
-        timeout-minutes: 120
+      - name: Test Iseberg core
+        timeout-minutes: 20
         shell: pwsh
-        run: |
-          $ErrorActionPreference = 'Stop'
-          $PSNativeCommandUseErrorActionPreference = $true
-          foreach ($project in @(
-            'Devolutions.Terminal.App.Tests',
-            'Devolutions.Terminal.UI.Tests',
-            'Devolutions.Terminal.Settings.Tests',
-            'Devolutions.Terminal.Settings.Editor.Tests'
-          )) {
-            dotnet test "tests/$project/$project.csproj" -c Release -m:1 `
-              -p:EnablePowerShellIse=true `
-              --logger "console;verbosity=normal" --logger trx `
-              --results-directory "artifacts/test-results/$project" `
-              --blame-hang --blame-hang-timeout 5min --blame-hang-dump-type none
-          }
+        run: ./scripts/Test-IsebergCore.ps1
 
       - name: Upload test diagnostics
         if: always()
diff --git a/docs/iseberg.md b/docs/iseberg.md
index ae5d2c7..d0a3cfd 100644
--- a/docs/iseberg.md
+++ b/docs/iseberg.md
@@ -268,15 +268,31 @@ excluded when the feature is off.
 CI publishes the feature-enabled NativeAOT desktop and verifies its package
 and module signatures. The separate `test-iseberg.yml` workflow tests Iseberg
 on Windows, Linux, and macOS using the pinned PowerShell 7.6.6 runtime. It runs
-the App, UI, Settings, and Settings.Editor test projects, not the entire
-solution, and checks terminal-only Windows x64/ARM64 NativeAOT publishes.
+`scripts/Test-IsebergCore.ps1` to select a fast core from the App, UI, Settings,
+and Settings.Editor projects, and checks terminal-only Windows x64/ARM64
+NativeAOT publishes. The core retains 220 of the 1,104 Iseberg cases in the
+original Windows run (80% fewer): inexpensive editor, installation, handshake,
+protocol, and child-process checks plus representative native-console execution,
+input, cancellation, recovery, profile, and settings-editor workflows. Exhaustive
+hosted workbench, theme, and native-input permutations are outside the CI core;
+the terminal-only workflow already covers unrelated terminal tests.
 Source/dependency changes, a weekly schedule, and
-manual dispatch trigger it; the extended suite does not gate release publication.
+manual dispatch trigger it; the core suite does not gate release publication.
 Iseberg CI runs test projects sequentially (`-m:1`) to avoid concurrent test-host
 startup starving short broker deadlines. It retains TRX results and per-test
-hang diagnostics and a 120-minute test-step budget for the slower hosted Windows
+hang diagnostics and a 20-minute test-step budget for the slower hosted Windows
 runner. A failed App test project stops the step before starting the UI suite.
 
+Run the same core locally after installing the test runtime:
+
+```powershell
+. ./scripts/Install-IsebergTestPowerShell.ps1
+./scripts/Test-IsebergCore.ps1
+```
+
+The full regression suite remains available through the unfiltered solution test
+command above; no regression tests have been deleted.
+
 Native libraries/helpers and legal notices remain loose for package signing and
 license checks. Ship only `Devolutions.Iseberg.PowerShell.dll` as loose
 content directly beside `dt.exe` and the desktop executable; it is not loaded into DT. Shared contract sources
diff --git a/scripts/Test-IsebergCore.ps1 b/scripts/Test-IsebergCore.ps1
new file mode 100644
index 0000000..62c9f6b
--- /dev/null
+++ b/scripts/Test-IsebergCore.ps1
@@ -0,0 +1,81 @@
+#Requires -Version 7.4
+[CmdletBinding()]
+param()
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = 'Stop'
+$PSNativeCommandUseErrorActionPreference = $true
+
+# Keep inexpensive editor/transport coverage and representative hosted workflows,
+# not the exhaustive workbench, theme, and native-input permutations.
+$tests = [ordered]@{
+    'Devolutions.Terminal.App.Tests' = @(
+        'PortableIseInstallationTests.'
+        'PortableIseHandshakeTests.'
+        'PortableIseProtocolTests.'
+        'PortableIseProcessTests.'
+        'PortableIseCoreTests.PersistenceLeaseContentionPreservesFirstOwnerAndLockBytes'
+        'PortableIseCoreTests.ReleasedRecoveryPreservesDirtyDraftFields'
+        'PortableIseCoreTests.LiveRecoveryRecordsOwnProcessButIsNotEligibleUntilReleased'
+        'PortableIseCoreTests.DirtySavedRecoveryRecordsAbsolutePathAndCurrentEncoding'
+        'PortableIseCoreTests.CleanSaveRemovesOnlyOwnSnapshot'
+        'PowerShellIseWorkspaceCatalogTests.ConcurrentProfileRecordsPublishOneOwnerAndNeverRebind'
+        'PowerShellIseWorkspaceCatalogTests.SameProfileReleasedWorkspaceIsFoundWithoutConsumingOrRewritingData'
+    )
+    'Devolutions.Terminal.UI.Tests' = @(
+        'PortableIseEditorTests.'
+        'IsebergTerminalBridgeTests.ScriptAndNativeConsoleSharePersistentRunspace'
+        'IsebergTerminalBridgeTests.NativeReadHostAcceptsResponseAndKeepsRunspaceUsable'
+        'IsebergTerminalBridgeTests.NativeCtrlCStopsRunningCommandAndRestoresInput'
+        'IsebergTerminalBridgeTests.MultilinePasteWaitsForExplicitEnter'
+        'IsebergTerminalBridgeTests.ResizeUpdatesRawUiColumnsWithoutReplacingEngine'
+        'IsebergNativeContinuationTests.ParenthesizedContinuationCompletedAfterFirstEnterExecutesExactlyOnce'
+        'IsebergNativeContinuationTests.CompleteInvalidInputPublishesOneParseErrorWithoutEnteringContinuation'
+        'PowerShellIseTabTests.DirtyCloseCancellationPreservesDocumentAndEngine'
+        'MainWindowPowerShellIseTests.SavedIseProfileLaunchesAndCapturesRealWorkbenchTab'
+        'PortableIseWorkbenchTests.ExplicitRecoverySavesExactDocumentsSelectionCaretAndReleasedOwnership'
+        'PortableIseWorkbenchTests.RecoverRoutesSameNamedDocumentsToSavedSessionsAndRestoresActiveSession'
+    )
+    'Devolutions.Terminal.Settings.Tests' = @(
+        'PowerShellIseProfileTests.IseDiscriminatorAndExplicitOptInResolve'
+        'PowerShellIseProfileTests.AddedIseProfileRoundTripsKindOptionsAndIdentity'
+        'PowerShellIseProfileTests.UnknownProfileTypeIsUnsupportedWithError'
+        'PowerShellIseProfileTests.NewIseProfileUsesIsebergNameAndDistinctIdentity'
+        'PowerShellIseProfileTests.TerminalProfilesAndOverridesRemainTerminal'
+        'PowerShellIseProfileTests.IseThemeDefaultsToClassicWithoutAddingThemeToLegacyTerminal'
+        'PowerShellIseProfileTests.UnknownIseThemeIsPreservedWithoutDefaultOrTerminalFallback'
+    )
+    'Devolutions.Terminal.Settings.Editor.Tests' = @(
+        'IseProfileHarmonizationTests.'
+    )
+}
+
+$elapsed = [Diagnostics.Stopwatch]::StartNew()
+Push-Location (Join-Path $PSScriptRoot '..')
+try {
+    foreach ($selection in $tests.GetEnumerator()) {
+        $project = $selection.Key
+        $filter = ($selection.Value | ForEach-Object { "FullyQualifiedName~$project.$_" }) -join '|'
+        $projectPath = Join-Path 'tests' (Join-Path $project "$project.csproj")
+        $resultsDirectory = Join-Path (Join-Path 'artifacts' 'test-results') $project
+        $resultsPath = Join-Path $resultsDirectory 'iseberg-core.trx'
+        if (Test-Path -LiteralPath $resultsPath) {
+            Remove-Item -LiteralPath $resultsPath
+        }
+
+        dotnet test $projectPath -c Release -m:1 `
+            -p:EnablePowerShellIse=true --filter $filter `
+            --logger 'console;verbosity=normal' --logger 'trx;LogFileName=iseberg-core.trx' `
+            --results-directory $resultsDirectory `
+            --blame-hang --blame-hang-timeout 5min --blame-hang-dump-type none
+
+        [xml]$results = Get-Content -LiteralPath $resultsPath -Raw
+        if ([int]$results.TestRun.ResultSummary.Counters.executed -eq 0) {
+            throw "The Iseberg core filter did not execute any tests in $project."
+        }
+    }
+    Write-Host "Iseberg core suite completed in $($elapsed.Elapsed)."
+}
+finally {
+    Pop-Location
+}