teamleaderleo · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026
@@ -28,6 +28,20 @@ on:
         required: false
         default: ""
         type: string
+      # Space-separated cmuxTests/ suites when `unit_suite` came from a diff
+      # that only edits those suites. `app-host unit tests` then runs just
+      # them on one worker instead of every suite on seven. Empty runs all.
+      unit_selectors:
+        required: false
+        default: ""
+        type: string
+      # `|`-delimited names of the strict steps below that own a suite in
+      # unit_selectors. A changed-suites run runs those steps as they are,
+      # since each gives its suites an app host and settings of their own.
+      unit_strict_steps:
+        required: false
+        default: ""
+        type: string
       product_artifacts:
         required: false
         default: "layered"
@@ -967,7 +981,7 @@ jobs:
     # transitive skip otherwise marks every macOS job skipped even when
     # linux-preflight itself succeeds. Require the direct needs explicitly.
     if: ${{ !cancelled() && needs.macos-compile-admission.result == 'success' && inputs.macos == 'true' && (inputs.full_suite == 'true' || inputs.unit_suite == 'true') }}
-    name: app-host unit tests (${{ matrix.shard }}/7)
+    name: ${{ inputs.unit_selectors != '' && 'app-host unit tests (changed suites)' || format('app-host unit tests ({0}/7)', matrix.shard) }}
     # App-host XCTest needs a runner that can broker testmanagerd control
     # sessions, so route through the shared MACOS_RUNNER_15 var like the other
     # macOS jobs. The fallback is what fork pull requests get, because
@@ -980,7 +994,9 @@ jobs:
       # only needs a verdict, and the first failure already is one.
       fail-fast: ${{ github.event_name == 'merge_group' }}
       matrix:
-        shard: [1, 2, 3, 4, 5, 6, 7]
+        # Shard 8 matches none of the numbered shards below that own a strict
+        # step, so a changed-suites run executes only its own batch.
+        shard: ${{ fromJSON(inputs.unit_selectors != '' && '[8]' || '[1, 2, 3, 4, 5, 6, 7]') }}
     env:
       CMUX_NODE_PRODUCT_CACHE_ROOT: ${{ vars.CMUX_NODE_PRODUCT_CACHE_ROOT }}
       CMUX_NODE_PRODUCT_CACHE_MAX_BYTES: ${{ vars.CMUX_NODE_PRODUCT_CACHE_MAX_BYTES }}
@@ -991,6 +1007,7 @@ jobs:
       # closed if a setup step or environment handoff loses either redirect.
       CMUX_CI_APP_HOST_ISOLATION_REQUIRED: "1"
       CMUX_APP_HOST_SHARD: ${{ matrix.shard }}
+      CMUX_APP_HOST_UNIT_SELECTORS: ${{ inputs.unit_selectors }}
       CMUX_APP_HOST_CAPTURE_XCRESULTS: "1"
       CMUX_CI_XCODE_APP: ${{ github.event_name == 'pull_request' && (vars.CMUX_CI_XCODE_APP_PR || vars.CMUX_CI_XCODE_APP_MACOS_15) || vars.CMUX_CI_XCODE_APP_MACOS_15 }}
       CMUX_CI_REQUIRED_MACOS_SDK_MAJOR: "26"
@@ -1241,7 +1258,7 @@ jobs:
           echo "CMUX_APP_HOST_TEST_INVENTORY=$inventory_json" >> "$GITHUB_ENV"
 
       - name: Upload built app-host test inventory
-        if: ${{ matrix.shard == 1 }}
+        if: ${{ matrix.shard == 1 || inputs.unit_selectors != '' }}
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: cmux-app-host-test-inventory-${{ github.run_id }}-${{ github.run_attempt }}
@@ -1266,7 +1283,7 @@ jobs:
           fi
 
       - name: Run My Devices regressions
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) || contains(inputs.unit_strict_steps, '|Run My Devices regressions|')) }}
         env:
           CMUX_APP_HOST_XCODEBUILD_ATTEMPTS: "1"
         run: |
@@ -1315,7 +1332,7 @@ jobs:
             test-without-building
 
       - name: Run Pi Feed ownership regressions
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) || contains(inputs.unit_strict_steps, '|Run Pi Feed ownership regressions|')) }}
         run: |
           # Swift Testing assertion failures are tolerated in the full sharded
           # app-host suite. Keep Feed ingestion and ownership on a non-tolerant
@@ -1339,7 +1356,7 @@ jobs:
 
       - name: Run remote tmux mirror detach and placement regressions
         id: remote-tmux-mirror
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) || contains(inputs.unit_strict_steps, '|Run remote tmux mirror detach and placement regressions|')) }}
         run: |
           # Closing a mirrored workspace must never kill the remote tmux session,
           # and --new-window must consolidate mirrors moved across source windows.
@@ -1444,7 +1461,7 @@ jobs:
           retention-days: 7
 
       - name: Run focused browser regressions
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run focused browser regressions|')) }}
         run: |
           # Focused gates for https://github.com/manaflow-ai/cmux/issues/7380 and #8054.
           # The tolerant full-suite step can crash-skip late suites (see #5888
@@ -1467,7 +1484,7 @@ jobs:
           done
 
       - name: Run remote tmux mirror active-pane regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run remote tmux mirror active-pane regression|')) }}
         run: |
           # Focused gates for https://github.com/manaflow-ai/cmux/issues/7372.
           # The tolerant full-suite step can crash-skip late suites (see #5888
@@ -1483,7 +1500,7 @@ jobs:
             test-without-building
 
       - name: Run remote tmux mirror layout identity regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run remote tmux mirror layout identity regression|')) }}
         run: |
           # The tolerant full-suite step may accept expected failures or stop
           # after an app-host crash. Keep #7833's identity suite non-tolerant
@@ -1498,7 +1515,7 @@ jobs:
             test-without-building
 
       - name: Run socket ACL reload regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run socket ACL reload regression|')) }}
         run: |
           # The tolerant full-suite step can accept assertion failures or
           # crash-skip late suites. Keep #7984's live reload and denial tests
@@ -1531,7 +1548,7 @@ jobs:
           CMUX_CLI_BIN="$CLI_BIN" python3 tests/test_cli_creation_initial_command.py
 
       - name: Run settings file-store no-op persistence regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run settings file-store no-op persistence regression|')) }}
         run: |
           # The broad app-host suite tolerates expected failures and can stop
           # after an app-host crash. Keep the settings persistence regression
@@ -1546,7 +1563,7 @@ jobs:
             test-without-building
 
       - name: Run issue 8373 sidebar convergence regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run issue 8373 sidebar convergence regression|')) }}
         timeout-minutes: 5
         run: |
           # The broad app-host suite tolerates Swift Testing assertion failures.
@@ -1572,7 +1589,7 @@ jobs:
           grep -F "ISSUE_8373_STRESS " "$test_log"
 
       - name: Run sidebar workspace-switch layout regression
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run sidebar workspace-switch layout regression|')) }}
         run: |
           # The tolerant full-suite step can accept Swift Testing assertion
           # failures when XCTest reports "0 unexpected". Keep #9612's real
@@ -1588,7 +1605,7 @@ jobs:
             test-without-building
 
       - name: Run terminal portal visibility regressions
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run terminal portal visibility regressions|')) }}
         run: |
           # These tests mutate the process-wide terminal portal registry and
           # include Swift Testing assertions that the tolerant broad shard can
@@ -1630,7 +1647,7 @@ jobs:
           node-version: "20"
 
       - name: Run Ghostty numeric locale tests
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_B_SHARD) || contains(inputs.unit_strict_steps, '|Run Ghostty numeric locale tests|')) }}
         run: |
           # LC_NUMERIC is process-global. Keep these tests in their own app-host
           # invocation and disable Xcode's parallel test execution for it.
@@ -1645,7 +1662,7 @@ jobs:
             test-without-building
 
       - name: Run global search shortcut regressions
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_GLOBAL_SEARCH_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_GLOBAL_SEARCH_SHARD) || contains(inputs.unit_strict_steps, '|Run global search shortcut regressions|')) }}
         timeout-minutes: 40
         run: |
           # This serialized container owns global shortcut settings. Keep its
@@ -1673,7 +1690,7 @@ jobs:
             "$test_log" cmuxTests/GlobalSearchShortcutBehaviorTests
 
       - name: Run Cloud machine ordering acceptance
-        if: ${{ !cancelled() && steps.prepare-app-host-home.outcome == 'success' && matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) }}
+        if: ${{ !cancelled() && steps.prepare-app-host-home.outcome == 'success' && (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) || contains(inputs.unit_strict_steps, '|Run Cloud machine ordering acceptance|')) }}
         timeout-minutes: 10
         run: |
           # Separate invocations prove each selector executed tests; a healthy
@@ -1705,6 +1722,11 @@ jobs:
           LOGICAL_BATCHES_PER_WORKER=2
           LOGICAL_SHARD_TOTAL=$((PHYSICAL_SHARD_TOTAL * LOGICAL_BATCHES_PER_WORKER))
           LOGICAL_SHARDS=("$PHYSICAL_SHARD" "$((PHYSICAL_SHARD + PHYSICAL_SHARD_TOTAL))")
+          if [ -n "${CMUX_APP_HOST_UNIT_SELECTORS:-}" ]; then
+            # A changed-suites run: one batch holding exactly those suites.
+            LOGICAL_SHARD_TOTAL=1
+            LOGICAL_SHARDS=(1)
+          fi
 
           # Each worker runs two balanced batches sequentially. Every invocation
           # writes to a regular file, and this script mirrors that file into the
@@ -1748,16 +1770,34 @@ jobs:
             for reservation in ${CMUX_APP_HOST_RESERVED_WALL_SECONDS:-}; do
               reserve_args+=(--reserve "$reservation")
             done
-            python3 scripts/ci/cmux_unit_test_shard.py \
-              --shard-index "$logical_shard" \
-              --shard-total "$LOGICAL_SHARD_TOTAL" \
-              --physical-shard-total "$PHYSICAL_SHARD_TOTAL" \
-              ${reserve_args[@]+"${reserve_args[@]}"} \
-              --output "$shard_args" || {
-                local shard_status=$?
-                echo "Failed to generate app-host unit-test batch ${logical_shard}/${LOGICAL_SHARD_TOTAL}"
-                return "$shard_status"
-              }
+            if [ -n "${CMUX_APP_HOST_UNIT_SELECTORS:-}" ]; then
+              # Suites a strict step owns ran in that step, not this batch.
+              python3 - "$shard_args" <<'PY'
+          import os
+          import sys
+          sys.path.insert(0, "scripts/ci")
+          from cmux_unit_test_shard import FOCUSED_GATE_SELECTORS
+          with open(sys.argv[1], "w", encoding="utf-8") as handle:
+              for selector in os.environ["CMUX_APP_HOST_UNIT_SELECTORS"].split():
+                  if selector not in FOCUSED_GATE_SELECTORS:
+                      handle.write(f"-only-testing:{selector}\n")
+          PY
+              if [ ! -s "$shard_args" ]; then
+                echo "Every changed suite ran in its strict step; no shared batch."
+                return 0
+              fi
+            else
+              python3 scripts/ci/cmux_unit_test_shard.py \
+                --shard-index "$logical_shard" \
+                --shard-total "$LOGICAL_SHARD_TOTAL" \
+                --physical-shard-total "$PHYSICAL_SHARD_TOTAL" \
+                ${reserve_args[@]+"${reserve_args[@]}"} \
+                --output "$shard_args" || {
+                  local shard_status=$?
+                  echo "Failed to generate app-host unit-test batch ${logical_shard}/${LOGICAL_SHARD_TOTAL}"
+                  return "$shard_status"
+                }
+            fi
             if [ ! -r "$shard_args" ]; then
               echo "Missing selector file for app-host unit-test batch ${logical_shard}/${LOGICAL_SHARD_TOTAL}"
               return 1
@@ -1936,7 +1976,7 @@ jobs:
           bun-version: "1.3.6"
 
       - name: Run agent notification semantics
-        if: ${{ matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) }}
+        if: ${{ (matrix.shard == fromJSON(env.CMUX_APP_HOST_FOCUSED_REGRESSION_SHARD) || contains(inputs.unit_strict_steps, '|Run agent notification semantics|')) }}
         run: |
           set -euo pipefail
           # Reuse compile admission's product instead of rebuilding the app in

@@ -70,6 +70,8 @@ jobs:
       ghosttykit_release: ${{ steps.unchanged_inputs.outputs.compile_admitted == 'true' && 'false' || steps.linux_guards.outputs.ghosttykit_release }}
       full_suite: ${{ steps.suite.outputs.full_suite }}
       unit_suite: ${{ steps.suite.outputs.unit_suite }}
+      unit_selectors: ${{ steps.suite.outputs.unit_selectors }}
+      unit_strict_steps: ${{ steps.suite.outputs.unit_strict_steps }}
       coverage_gap: ${{ steps.suite.outputs.coverage_gap }}
       compile_admitted: ${{ steps.unchanged_inputs.outputs.compile_admitted == 'true' && 'true' || steps.admitted.outputs.compile_admitted }}
       source_tree: ${{ steps.source-identity.outputs.tree }}
@@ -150,6 +152,11 @@ jobs:
               emit_all_areas
               exit 0
             fi
+            # The changed lines of cmuxTests/, so choose_ci_suite.py can tell
+            # which declarations a test edit touched. Absent reads as "every
+            # line of each changed file".
+            git diff --no-renames -U0 "$BASE_SHA" "$MERGE_SHA" -- cmuxTests \
+              > /tmp/cmux-ci-tests.diff || rm -f /tmp/cmux-ci-tests.diff
 
             if [ ! -s /tmp/cmux-ci-changed-files.txt ]; then
               echo "PR diff is empty; skipping product-area CI."
@@ -465,6 +472,9 @@ jobs:
           if [ -f /tmp/cmux-ci-changed-files.txt ]; then
             files_args=(--files-from /tmp/cmux-ci-changed-files.txt)
           fi
+          if [ -f /tmp/cmux-ci-tests.diff ]; then
+            files_args+=(--diff-from /tmp/cmux-ci-tests.diff)
+          fi
           python3 scripts/ci/choose_ci_suite.py \
             --event-name "$EVENT_NAME" \
             --pull-request-policy "$PULL_REQUEST_POLICY" \
@@ -969,6 +979,8 @@ jobs:
       macos: ${{ needs.changes.outputs.macos }}
       full_suite: ${{ needs.changes.outputs.full_suite }}
       unit_suite: ${{ needs.changes.outputs.unit_suite }}
+      unit_selectors: ${{ needs.changes.outputs.unit_selectors }}
+      unit_strict_steps: ${{ needs.changes.outputs.unit_strict_steps }}
       swift_packages: ${{ needs.changes.outputs.swift_packages }}
       compile_admitted: ${{ needs.changes.outputs.compile_admitted }}
       release_build: ${{ needs.changes.outputs.release_build }}

diff --git a/CLAUDE.md b/CLAUDE.md
@@ -216,7 +216,10 @@ Add `full-ci` only when the user or agreed validation plan explicitly calls for
 the broad suite; state which additional lanes are needed and why.
 
 Normal PR CI can already run routed tests, including Swift package and CLI
-wrapper checks, without `full-ci`. The label permits eligible app-host shards,
+wrapper checks, without `full-ci`. A `cmuxTests/` diff runs the suites it
+declares or extends on one app-host worker, with no label. `unit-ci` runs every
+app-host suite across all seven workers; `full-ci` adds the other lanes on top.
+Neither is needed to test the suites you edited. The label permits eligible app-host shards,
 lag builds, and other full-suite lanes; path routing, release routing, and job
 dependencies still apply. It does not request every repository test. Inspect
 actual executed tests on the current SHA: a green skipped job is not coverage.