diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 2ac5eb7..bc03f39 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -9,6 +9,14 @@ on:
   schedule:
     - cron: '0 6 * * 1'
 
+# Estate guardrail: cancel superseded runs so re-pushes / rebased PR
+# updates do not pile up queued runs against the shared account-wide
+# Actions concurrency pool. Applied only to read-only check workflows
+# (no publish/mutation), so cancelling a superseded run is always safe.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/governance.yml b/.github/workflows/governance.yml
index 76bd1a0..4bb50e9 100644
--- a/.github/workflows/governance.yml
+++ b/.github/workflows/governance.yml
@@ -18,6 +18,14 @@ on:
   pull_request:
   workflow_dispatch:
 
+# Estate guardrail: cancel superseded runs so re-pushes / rebased PR
+# updates do not pile up queued runs against the shared account-wide
+# Actions concurrency pool. Applied only to read-only check workflows
+# (no publish/mutation), so cancelling a superseded run is always safe.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/scorecard-enforcer.yml b/.github/workflows/scorecard-enforcer.yml
index 0b7ab03..e7bcc59 100644
--- a/.github/workflows/scorecard-enforcer.yml
+++ b/.github/workflows/scorecard-enforcer.yml
@@ -8,6 +8,14 @@ on:
     - cron: '0 6 * * 1'
   workflow_dispatch:
 
+# Estate guardrail: cancel superseded runs so re-pushes / rebased PR
+# updates do not pile up queued runs against the shared account-wide
+# Actions concurrency pool. Applied only to read-only check workflows
+# (no publish/mutation), so cancelling a superseded run is always safe.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/scorecard.yml b/.github/workflows/scorecard.yml
index 007344c..700eeb3 100644
--- a/.github/workflows/scorecard.yml
+++ b/.github/workflows/scorecard.yml
@@ -7,6 +7,14 @@ on:
     - cron: '0 4 * * *'
   workflow_dispatch:
 
+# Estate guardrail: cancel superseded runs so re-pushes / rebased PR
+# updates do not pile up queued runs against the shared account-wide
+# Actions concurrency pool. Applied only to read-only check workflows
+# (no publish/mutation), so cancelling a superseded run is always safe.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/secret-scanner.yml b/.github/workflows/secret-scanner.yml
index 740b59d..1810bee 100644
--- a/.github/workflows/secret-scanner.yml
+++ b/.github/workflows/secret-scanner.yml
@@ -6,6 +6,14 @@ on:
   push:
     branches: [main]
 
+# Estate guardrail: cancel superseded runs so re-pushes / rebased PR
+# updates do not pile up queued runs against the shared account-wide
+# Actions concurrency pool. Applied only to read-only check workflows
+# (no publish/mutation), so cancelling a superseded run is always safe.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read