diff --git a/.github/workflows/wai-conformance.yml b/.github/workflows/wai-conformance.yml
index 080668132..09ffa3f0c 100644
--- a/.github/workflows/wai-conformance.yml
+++ b/.github/workflows/wai-conformance.yml
@@ -713,7 +713,7 @@ jobs:
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
     name: v2 vocabulary · manifests validate as stated
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-python@v5
@@ -743,7 +743,7 @@ jobs:
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
     name: independent verifiers · claims, JWP, key discovery and integer payloads (Python)
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
 
@@ -903,7 +903,7 @@ jobs:
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
     name: delivery telemetry · CMCD and CMSD against an independent library
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-node@v4
@@ -1049,7 +1049,7 @@ jobs:
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
     name: C2PA manifest emission · signed, read back, validated
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v4
 
diff --git a/.github/workflows/wai-http.yml b/.github/workflows/wai-http.yml
index 29cddddae..6e77740b0 100644
--- a/.github/workflows/wai-http.yml
+++ b/.github/workflows/wai-http.yml
@@ -165,7 +165,7 @@ jobs:
   # schedule has no pull-request context and runs everything.
   relevant:
     name: WAI HTTP · does this change touch it
-    runs-on: linux
+    runs-on: linux-arm64
     outputs:
       run: ${{ steps.gate.outputs.run }}
     steps:
@@ -187,7 +187,7 @@ jobs:
     name: HTTP corpus · falsify ${{ matrix.shard }}
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     strategy:
       fail-fast: false
       matrix:
@@ -233,7 +233,7 @@ jobs:
     name: HTTP corpus · every patch and mutation in exactly one shard
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - shell: bash
@@ -247,7 +247,7 @@ jobs:
     name: HTTP corpus · verified both ways, and the differential
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
 
@@ -285,7 +285,7 @@ jobs:
     name: cache rules · controls and labelled caches
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
 
diff --git a/.github/workflows/wai-pack.yml b/.github/workflows/wai-pack.yml
index ef3999f3d..3462a69db 100644
--- a/.github/workflows/wai-pack.yml
+++ b/.github/workflows/wai-pack.yml
@@ -74,7 +74,7 @@ jobs:
   # `true` — a push to main runs everything, as before.
   relevant:
     name: wai-pack · does this change touch it
-    runs-on: linux
+    runs-on: linux-arm64
     outputs:
       run: ${{ steps.gate.outputs.run }}
     steps:
@@ -160,7 +160,7 @@ jobs:
     name: wai-pack · independent verifier (Python)
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-python@v5
@@ -238,7 +238,7 @@ jobs:
     name: wai-pack · the floor through a media prober
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - name: Install a media prober
@@ -274,7 +274,7 @@ jobs:
     name: wai-pack · dependency licences
     needs: relevant
     if: needs.relevant.outputs.run == 'true'
-    runs-on: linux
+    runs-on: linux-arm64
     steps:
       - uses: actions/checkout@v5
       - name: Install Rust 1.98.0