lawrencecchen · May 30, 2026 · May 30, 2026 · May 30, 2026 · Jun 1, 2026 · Jun 2, 2026
diff --git a/.github/actionlint.yaml b/.github/actionlint.yaml
@@ -1,12 +1,10 @@
 self-hosted-runner:
   labels:
-    # Active default lives in the MACOS_RUNNER_15 / MACOS_RUNNER_26 repo
-    # variables; these are the literal labels referenced as fallbacks or as
-    # manual workflow_dispatch choices. See docs/macos-ci-runners.md.
+    # macOS jobs run on Blacksmith (hardcoded in the workflows). These are the
+    # labels referenced directly or offered as manual workflow_dispatch choices.
+    # See docs/macos-ci-runners.md.
     - blacksmith-6vcpu-macos-15
     - blacksmith-6vcpu-macos-26
     - blacksmith-6vcpu-macos-latest
-    - warp-macos-15-arm64-6x
-    - warp-macos-26-arm64-6x
     - depot-macos-latest
     - depot-macos-14
@@ -9,7 +9,7 @@ concurrency:
 
 jobs:
   build-ghosttykit:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 20
     env:
       GHOSTTYKIT_CRASH_REPORT_SUBDIR: cmux/crash

@@ -9,12 +9,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+          - os: blacksmith-6vcpu-macos-15
             timeout: 30
             startup_smoke: true
             virtual_display: true
             skip_zig: false
-          - os: ${{ vars.MACOS_RUNNER_26 || 'warp-macos-26-arm64-6x' }}
+          - os: blacksmith-6vcpu-macos-26
             timeout: 30
             startup_smoke: true
             virtual_display: false

@@ -170,7 +170,13 @@ jobs:
           bun test tests/vm-db-read-model.test.ts
 
   tests:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    # macOS CI runs on Blacksmith (hardcoded, git-tracked; no override variable).
+    # To change provider or roll back to Warp, edit the runs-on labels in a PR.
+    # macos-15 vs macos-26: helper / GhosttyKit / nightly jobs build on macos-15
+    # because zig can only cross-link the universal Ghostty CLI helper against a
+    # pre-26 SDK; the app and SDK-validation builds use macos-26 (Liquid Glass).
+    # See docs/macos-ci-runners.md.
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 75
     env:
       CMUX_SKIP_ZIG_BUILD: "1"
@@ -427,7 +433,7 @@ jobs:
     # Keep lag validation separate from UI regressions so functional UI failures
     # and performance regressions stay isolated. Broader interactive UI suites
     # still run via test-e2e.yml on GitHub-hosted runners.
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     # A cold DerivedData cache (any project.pbxproj or Package.resolved change
     # mints a new cache key with no restore-keys fallback) forces a full
     # cmux build whose Swift codegen alone can run 20+ min. Project/package
@@ -622,7 +628,7 @@ jobs:
           rm -f /tmp/create-virtual-display
 
   release-ghostty-cli-helper:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 20
     steps:
       - name: Checkout
@@ -661,7 +667,7 @@ jobs:
     # mistakes before they reach main.
     # Keep the app build on macOS 26 so SDK-gated SwiftUI Liquid Glass code
     # compiles into the same artifact shape as nightly and stable releases.
-    runs-on: ${{ vars.MACOS_RUNNER_26 || 'warp-macos-26-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-26
     timeout-minutes: 20
     steps:
       - name: Checkout
@@ -770,7 +776,7 @@ jobs:
           [[ "$SDK_VERSION" == 26.* ]]
 
   ui-regressions:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     # Cold builds after project/package changes can spend more than 25 minutes
     # in build-for-testing before the UI regression script starts.
     timeout-minutes: 45

@@ -107,7 +107,7 @@ jobs:
     # and injected before signing (see Select Xcode + the helper build/inject
     # steps). Building the whole app with Xcode 16 (#5022) shipped a macOS 15 SDK
     # binary that Tahoe forced into the legacy non-Liquid-Glass appearance.
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 30
     steps:
       - name: Checkout build ref

@@ -9,7 +9,7 @@ on:
         required: false
         default: ""
       runner:
-        description: macOS runner (auto follows the MACOS_RUNNER_15 repo variable, then warp)
+        description: macOS runner (auto uses the Blacksmith default)
         required: false
         default: auto
         type: choice
@@ -18,8 +18,6 @@ on:
           - blacksmith-6vcpu-macos-15
           - blacksmith-6vcpu-macos-26
           - blacksmith-6vcpu-macos-latest
-          - warp-macos-15-arm64-6x
-          - warp-macos-26-arm64-6x
       workspace_count:
         description: Fixture workspace count
         required: false
@@ -39,7 +37,7 @@ concurrency:
 
 jobs:
   activation-session:
-    runs-on: ${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}
+    runs-on: ${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}
     timeout-minutes: 45
     env:
       PERF_TAG: perfci
@@ -94,8 +92,8 @@ jobs:
         uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
         with:
           path: .ci-source-packages
-          key: spm-${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}-${{ hashFiles('cmux.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved') }}
-          restore-keys: spm-${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}-
+          key: spm-${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}-${{ hashFiles('cmux.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved') }}
+          restore-keys: spm-${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}-
 
       - name: Resolve Swift packages
         run: |

@@ -16,7 +16,7 @@ env:
 
 jobs:
   build-ghostty-cli-helper:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 20
     steps:
       - name: Checkout
@@ -53,7 +53,7 @@ jobs:
     # Build the app on macOS 26 so SDK-gated SwiftUI Liquid Glass code compiles
     # into stable releases. The real universal Ghostty CLI helper is built on
     # macOS 15 above because Zig 0.15.2 cannot link it on macOS 26.
-    runs-on: ${{ vars.MACOS_RUNNER_26 || 'warp-macos-26-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-26
     timeout-minutes: 20
     steps:
       - name: Checkout

@@ -28,7 +28,7 @@ on:
 
 jobs:
   tests:
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
     timeout-minutes: 20
     steps:
       - name: Checkout

@@ -1,5 +1,5 @@
 name: E2E test with video recording
-run-name: ${{ inputs.test_filter }} on ${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }} @ ${{ inputs.ref || github.ref_name }}
+run-name: ${{ inputs.test_filter }} on ${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }} @ ${{ inputs.ref || github.ref_name }}
 
 on:
   workflow_dispatch:
@@ -21,7 +21,7 @@ on:
         default: true
         type: boolean
       runner:
-        description: "Runner OS (auto follows the MACOS_RUNNER_15 repo variable, then warp; pick depot-macos-* for GUI activation)"
+        description: "Runner OS (auto uses the Blacksmith default; pick depot-macos-* for GUI activation)"
         required: false
         default: "auto"
         type: choice
@@ -30,26 +30,24 @@ on:
           - blacksmith-6vcpu-macos-15
           - blacksmith-6vcpu-macos-26
           - blacksmith-6vcpu-macos-latest
-          - warp-macos-15-arm64-6x
-          - warp-macos-26-arm64-6x
           - depot-macos-latest
           - depot-macos-14
 
 concurrency:
-  group: e2e-${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}-${{ inputs.ref || github.ref_name }}-${{ inputs.test_filter }}
+  group: e2e-${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}-${{ inputs.ref || github.ref_name }}-${{ inputs.test_filter }}
   cancel-in-progress: true
 
 jobs:
   e2e:
-    runs-on: ${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}
+    runs-on: ${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}
     timeout-minutes: 20
     env:
       TEST_REF: ${{ inputs.ref || github.ref }}
     steps:
       - name: Validate Depot runner identity
-        if: ${{ startsWith((!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner, 'depot-macos-') }}
+        if: ${{ startsWith((!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner, 'depot-macos-') }}
         env:
-          REQUESTED_RUNNER: ${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}
+          REQUESTED_RUNNER: ${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}
           RUNNER_CONTEXT_NAME: ${{ runner.name }}
         run: |
           set -euo pipefail
@@ -232,8 +230,8 @@ jobs:
         uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
         with:
           path: .ci-source-packages
-          key: spm-${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}-${{ hashFiles('cmux.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved') }}
-          restore-keys: spm-${{ (!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner }}-
+          key: spm-${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}-${{ hashFiles('cmux.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved') }}
+          restore-keys: spm-${{ (!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner }}-
 
       - name: Resolve Swift packages
         run: |

@@ -61,7 +61,7 @@ jobs:
 
   terminal-nightly:
     if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
-    runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
+    runs-on: blacksmith-6vcpu-macos-15
-    runs-on: blacksmith-6vcpu-macos-15
+    runs-on: ${{ vars.MACOS_RUNNER_15 || 'blacksmith-6vcpu-macos-15' }}
-    runs-on: blacksmith-6vcpu-macos-15
+    runs-on: ${{ vars.MACOS_RUNNER_15 || 'blacksmith-6vcpu-macos-15' }}
     timeout-minutes: 30
     steps:
       - name: Checkout

diff --git a/docs/macos-ci-runners.md b/docs/macos-ci-runners.md
@@ -1,44 +1,22 @@
 # macOS CI runners
 
-All paid macOS CI/CD jobs pick their runner from two repository variables instead of a hardcoded label:
+All paid macOS CI/CD jobs run on Blacksmith. The runner labels are hardcoded in the workflows (git-tracked); there is no repo-variable override.
-All paid macOS CI/CD jobs run on Blacksmith. The runner labels are hardcoded in the workflows (git-tracked); there is no repo-variable override.
+All paid macOS CI/CD jobs default to Blacksmith. Runner labels are git-tracked in workflows, manual workflows can still choose explicit runner options, and there is no repo-variable override.
-All paid macOS CI/CD jobs run on Blacksmith. The runner labels are hardcoded in the workflows (git-tracked); there is no repo-variable override.
+All paid macOS CI/CD jobs default to Blacksmith. Runner labels are git-tracked in workflows, manual workflows can still choose explicit runner options, and there is no repo-variable override.
 
-- `MACOS_RUNNER_15` for jobs that build the real universal Release app, including nightly, stable release, `release-build`, and the e2e/perf defaults.
-- `MACOS_RUNNER_26` for macOS 26 compatibility coverage and jobs that do not need Zig to build the real universal Ghostty CLI helper.
+- `blacksmith-6vcpu-macos-15` for jobs that build the universal Ghostty CLI helper (zig 0.15.2 can only cross-link the x86_64 slice against a pre-26 SDK), for the GhosttyKit framework build, for unit/UI tests, and for the nightly app build (which uses Xcode 26 on the macOS 15 host).
+- `blacksmith-6vcpu-macos-26` for the app builds that must link the macOS 26 SDK so SDK-gated SwiftUI Liquid Glass code compiles in: stable `release` `build-sign-notarize` and the CI `release-build` SDK-validation lane. `ci-macos-compat.yml` also exercises macOS 26 with `CMUX_SKIP_ZIG_BUILD=1`.
 
-Workflows reference them as `runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}`. If a variable is unset, the job falls back to WarpBuild, so CI is never broken by a missing variable.
+Workflows reference these labels directly, e.g. `runs-on: blacksmith-6vcpu-macos-15`.
 
-Nightly and stable release stay on macOS 15 until Zig can link the real universal Ghostty CLI helper on macOS 26. `ci-macos-compat.yml` still covers macOS 26 by setting `CMUX_SKIP_ZIG_BUILD=1`, but publishing workflows cannot use that stub because the signed artifacts must include the real helper.
+## Changing the runner
 
-## Switch Blacksmith <-> WarpBuild
+To switch providers or roll back to Warp, edit the `runs-on` labels in `.github/workflows/*.yml` and open a PR. There is no variable to flip; the runner choice lives in git so every change is reviewed and recorded.
 
-The switch is a repo-variable change. It takes effect on the next workflow run, with no PR or commit.
-
-Use Blacksmith (default):
-
-```bash
-gh variable set MACOS_RUNNER_15 --repo manaflow-ai/cmux -b blacksmith-6vcpu-macos-15
-gh variable set MACOS_RUNNER_26 --repo manaflow-ai/cmux -b blacksmith-6vcpu-macos-26
-```
-
-Fall back to WarpBuild (e.g. Blacksmith macOS capacity is queuing, as happened in https://github.com/manaflow-ai/cmux/pull/4926):
-
-```bash
-gh variable delete MACOS_RUNNER_15 --repo manaflow-ai/cmux
-gh variable delete MACOS_RUNNER_26 --repo manaflow-ai/cmux
-```
-
-Deleting the variables reverts to the WarpBuild fallback baked into the workflows. You can also set them explicitly to `warp-macos-15-arm64-6x` / `warp-macos-26-arm64-6x`.
-
-Check current values:
-
-```bash
-gh variable list --repo manaflow-ai/cmux
-```
+If a new runner label is introduced, add it to `.github/actionlint.yaml` so `actionlint` recognizes it.
 
 ## Manual runs
 
-`perf-activation.yml` and `test-e2e.yml` keep a `runner` choice input that defaults to `auto`. `auto` (and the empty `pull_request` case for perf) follows `MACOS_RUNNER_15` then the Warp fallback, so flipping the repo variable also redirects these workflows. An explicit choice wins over the variable; both dropdowns expose `warp-macos-15-arm64-6x` / `warp-macos-26-arm64-6x` so an operator can pick Warp directly during a Blacksmith outage. `test-e2e.yml` also keeps `depot-macos-*` choices and a Depot identity guard for GUI-activation runs.
+`perf-activation.yml` and `test-e2e.yml` keep a `runner` choice input that defaults to `auto`. `auto` (and the empty `pull_request` case for perf) resolves to the hardcoded Blacksmith default; an explicit choice wins. `test-e2e.yml` also keeps `depot-macos-*` choices and a Depot identity guard for GUI-activation runs.
 
 ## Guard
 
-`tests/test_ci_self_hosted_guard.sh` (run by the `workflow-guard-tests` job) asserts every paid macOS job references `vars.MACOS_RUNNER_*` or a Blacksmith/Warp label, so a job can never silently fall back to a free GitHub-hosted runner. Keep new labels in `.github/actionlint.yaml`.
+`tests/test_ci_self_hosted_guard.sh` (run by the `workflow-guard-tests` job) asserts every paid macOS job references a Blacksmith label, so a job can never silently fall back to a free GitHub-hosted runner. `tests/test_ci_release_sdk_lane.sh` asserts the release/CI app builds use macOS 26 with a macOS-15-built helper.
diff --git a/tests/test_ci_release_sdk_lane.sh b/tests/test_ci_release_sdk_lane.sh
@@ -32,25 +32,25 @@ require_job_contains() {
 require_job_contains \
   "$RELEASE_FILE" \
   "build-ghostty-cli-helper" \
-  'runs-on: ${{ vars.MACOS_RUNNER_15 || '\''warp-macos-15-arm64-6x'\'' }}' \
+  'runs-on: blacksmith-6vcpu-macos-15' \
   "release must build the real Ghostty CLI helper on macOS 15"
 
 require_job_contains \
   "$RELEASE_FILE" \
   "build-sign-notarize" \
-  'runs-on: ${{ vars.MACOS_RUNNER_26 || '\''warp-macos-26-arm64-6x'\'' }}' \
+  'runs-on: blacksmith-6vcpu-macos-26' \
   "release must build the app on macOS 26"
 
 require_job_contains \
   "$CI_FILE" \
   "release-ghostty-cli-helper" \
-  'runs-on: ${{ vars.MACOS_RUNNER_15 || '\''warp-macos-15-arm64-6x'\'' }}' \
+  'runs-on: blacksmith-6vcpu-macos-15' \
   "CI must build the real Ghostty CLI helper on macOS 15"
 
 require_job_contains \
   "$CI_FILE" \
   "release-build" \
-  'runs-on: ${{ vars.MACOS_RUNNER_26 || '\''warp-macos-26-arm64-6x'\'' }}' \
+  'runs-on: blacksmith-6vcpu-macos-26' \
   "CI release-build must compile the app on macOS 26"
 
 for workflow in "$CI_FILE" "$RELEASE_FILE"; do

diff --git a/tests/test_ci_self_hosted_guard.sh b/tests/test_ci_self_hosted_guard.sh
@@ -1,9 +1,8 @@
 #!/usr/bin/env bash
 # Regression test for https://github.com/manaflow-ai/cmux/issues/385.
-# Ensures paid CI jobs use a paid macOS runner (Blacksmith or WarpBuild, routed
-# through the MACOS_RUNNER_15 / MACOS_RUNNER_26 repo variables), never a free
-# GitHub-hosted runner. Flip Blacksmith<->Warp by editing those repo variables;
-# see docs/macos-ci-runners.md.
+# Ensures paid CI jobs use a paid macOS runner (a Blacksmith label), never a
+# free GitHub-hosted runner. Runners are hardcoded in the workflows; see
+# docs/macos-ci-runners.md.
 # Fork PRs are gated by GitHub's built-in "Require approval for outside
 # collaborators" setting, so workflow-level fork guards are not needed.
 set -euo pipefail
@@ -19,11 +18,11 @@ check_macos_runner() {
   if ! awk -v job="$job" '
     $0 ~ "^  "job":" { in_job=1; next }
     in_job && /^  [^[:space:]#][^:]*:[[:space:]]*(#.*)?$/ { in_job=0 }
-    in_job && /runs-on:.*(vars\.MACOS_RUNNER|blacksmith-[0-9]+vcpu-macos-|warp-macos-[0-9]+-arm64)/ { saw=1 }
-    in_job && /os:.*(vars\.MACOS_RUNNER|blacksmith-[0-9]+vcpu-macos-|warp-macos-[0-9]+-arm64)/ { saw=1 }
+    in_job && /runs-on:.*blacksmith-[0-9]+vcpu-macos-/ { saw=1 }
+    in_job && /os:.*blacksmith-[0-9]+vcpu-macos-/ { saw=1 }
     END { exit !(saw) }
   ' "$file"; then
-    echo "FAIL: $job in $(basename "$file") must run on a paid macOS runner (vars.MACOS_RUNNER_* or a Blacksmith/Warp label), not a GitHub-hosted runner"
+    echo "FAIL: $job in $(basename "$file") must run on a paid macOS runner (a Blacksmith label), not a GitHub-hosted runner"
     exit 1
   fi
   echo "PASS: $job in $(basename "$file") uses a paid macOS runner"
@@ -61,7 +60,7 @@ check_e2e_runner_fallbacks() {
     exit 1
   fi
 
-  if ! grep -Fq "startsWith((!inputs.runner || inputs.runner == 'auto') && (vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x') || inputs.runner, 'depot-macos-')" "$E2E_FILE"; then
+  if ! grep -Fq "startsWith((!inputs.runner || inputs.runner == 'auto') && 'blacksmith-6vcpu-macos-15' || inputs.runner, 'depot-macos-')" "$E2E_FILE"; then
     echo "FAIL: test-e2e.yml must validate all Depot macOS runner choices"
     exit 1
   fi
@@ -133,7 +132,7 @@ check_macos_runner "$CI_FILE" "ui-regressions"
 # build-ghosttykit.yml
 check_macos_runner "$GHOSTTYKIT_FILE" "build-ghosttykit"
 
-# ci-macos-compat.yml (matrix.os routed through the MACOS_RUNNER_* repo vars)
+# ci-macos-compat.yml (matrix.os uses hardcoded Blacksmith labels)
 check_macos_runner "$COMPAT_FILE" "compat-tests"
 
 # test-e2e.yml is manual, so keep the Depot GUI runner choices but cancel