diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 3d0bb37ca..2cdd06e0c 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -187,6 +187,7 @@ jobs:
               - 'operator/config/**'
               - 'charts/gameplane/crds/**'
               - 'charts/gameplane/crd-manifests/**'
+              - 'hack/check-codegen-drift_test.sh'
             ci:
               - '.github/workflows/ci.yaml'
               - '.github/actions/**'
@@ -517,6 +518,32 @@ jobs:
       - name: test up.sh registry/context bootstrap
         run: make test-up-registry
 
+  # Spec 013 G5: regenerated files (deepcopy, operator/config/{crd,rbac}, chart
+  # CRDs, go.mod/go.sum) must be committed with the change that needs them. The
+  # proof step shows the gate goes red on a types edit committed without regenerating.
+  codegen-drift:
+    name: codegen drift
+    needs: [changes]
+    if: needs.changes.outputs.codegen == 'true' || github.event_name == 'push'
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: ./.github/actions/go-cache
+        with:
+          key-suffix: codegen-drift
+      - uses: azure/setup-helm@9bc31f4ebc9c6b171d7bfbaa5d006ae7abdb4310 # v5.0.1
+      - name: regenerate deepcopy, CRDs, RBAC and chart CRD copies
+        run: make generate manifests
+      - name: go mod tidy across modules
+        run: make tidy
+      - name: fail on drift
+        run: git diff --exit-code
+      - name: prove the gate fails on a stale types edit
+        run: ./hack/check-codegen-drift_test.sh
+
   lint:
     name: lint (${{ matrix.module }})
     needs: [changes]
@@ -1957,6 +1984,7 @@ jobs:
         build-images-arm64,
         capture-sidecar-setcap-proof,
         docs,
+        codegen-drift,
         lint,
         go,
         web,
@@ -2068,7 +2096,7 @@ jobs:
 
             const NEEDS_ORDER = [
               'changes', 'build-images', 'build-images-arm64',
-              'capture-sidecar-setcap-proof', 'docs', 'lint', 'go',
+              'capture-sidecar-setcap-proof', 'docs', 'codegen-drift', 'lint', 'go',
               'web', 'web-e2e-mock', 'helm', 'chart-template', 'workflow-lint', 'go-e2e-unit',
               'api-postgres',
               'e2e-buckets', 'e2e-go', 'e2e-go-arm64', 'e2e-multicluster', 'e2e-multicluster-arm64', 'e2e-upgrade', 'e2e-upgrade-arm64',
@@ -2084,6 +2112,7 @@ jobs:
               'build-images-arm64': (n) => n === 'build e2e images (arm64)',
               'capture-sidecar-setcap-proof': (n) => n === 'capture-sidecar CAP_NET_RAW survival',
               docs: (n) => n === 'docs and repository checks',
+              'codegen-drift': (n) => n === 'codegen drift',
               lint: (n) => n.startsWith('lint ('),
               go: (n) => n.startsWith('go (') && n !== 'go (test/e2e)',
               web: (n) => n === 'web',
diff --git a/go.work.sum b/go.work.sum
index a5c49ede0..85adc7e80 100644
--- a/go.work.sum
+++ b/go.work.sum
@@ -457,6 +457,7 @@ github.com/poy/onpar v1.1.2/go.mod h1:6X8FLNoxyr9kkmnlqpK6LSoiOtrO6MICtWwEuWkLjz
 github.com/pquerna/cachecontrol v0.1.0/go.mod h1:NrUG3Z7Rdu85UNR3vm7SOsl1nFIeSiQnrHV5K9mBcUI=
 github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
 github.com/prometheus/client_golang v1.20.4/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
+github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
 github.com/prometheus/otlptranslator v0.0.2/go.mod h1:P8AwMgdD7XEr6QRUJ2QWLpiAZTgTE2UYgjlu3svompI=
 github.com/prometheus/otlptranslator v1.0.0/go.mod h1:vRYWnXvI6aWGpsdY/mOT/cbeVRBlPWtBNDb7kGR3uKM=
 github.com/prometheus/procfs v0.21.0/go.mod h1:aB55Cww9pdSJVHk0hUf0inxWyyjPogFIjmHKYgMKmtY=
diff --git a/hack/check-codegen-drift_test.sh b/hack/check-codegen-drift_test.sh
new file mode 100755
index 000000000..e200a884a
--- /dev/null
+++ b/hack/check-codegen-drift_test.sh
@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# check-codegen-drift_test.sh: Proof that the "codegen drift" CI gate fails on a
+# types edit committed without regenerating (spec 013 G5,
+# specs/013-expand-test-coverage/contracts/static-gates.md).
+#
+# The gate is: make generate manifests && make tidy && git diff --exit-code
+# run inside a checkout. This script runs it in a throwaway detached worktree:
+#
+#   Case 1 (must FAIL): a probe commit edits
+#     operator/api/v1alpha1/gameserver_types.go (doc comment + json tag of
+#     Suspend) without regenerating. The gate must exit non-zero.
+#   Case 2 (must PASS): the probe commit is dropped; the clean checkout must
+#     pass the gate.
+#
+# The main working tree is never modified. The worktree and temp dir are
+# removed on exit.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "$SCRIPT_DIR/.."
+REPO_ROOT="$(pwd)"
+
+TYPES_FILE="operator/api/v1alpha1/gameserver_types.go"
+TAG_OLD='json:"suspend,omitempty"'
+TAG_NEW='json:"suspendDriftProbe,omitempty"'
+DOC_LINE='// DriftProbe: doc comment added by hack/check-codegen-drift_test.sh.'
+
+tmp="$(mktemp -d)"
+wt="$tmp/wt"
+
+cleanup() {
+  git -C "$REPO_ROOT" worktree remove --force "$wt" >/dev/null 2>&1 || true
+  rm -rf "$tmp"
+}
+trap cleanup EXIT
+
+# gate DIR: regenerate, tidy, then require a clean tree.
+gate() {
+  local dir="$1"
+  (cd "$dir" && make generate manifests && make tidy && git diff --exit-code)
+}
+
+git worktree add --detach "$wt" HEAD >/dev/null
+
+echo "== Case 1: stale types edit committed without regenerating (expect FAIL)"
+
+# Insert the doc comment above the first `Suspend bool` field and rename its
+# json tag, on that same line only.
+line_no="$(grep -n -m1 -F "	Suspend bool \`$TAG_OLD\`" "$wt/$TYPES_FILE" | cut -d: -f1 || true)"
+if [[ -z "$line_no" ]]; then
+  echo "✗ could not find the Suspend field in $TYPES_FILE" >&2
+  exit 1
+fi
+awk -v ln="$line_no" -v old="$TAG_OLD" -v new="$TAG_NEW" -v doc="	$DOC_LINE" '
+  NR == ln {
+    print doc
+    sub(old, new)
+  }
+  { print }
+' "$wt/$TYPES_FILE" > "$tmp/types.go"
+cat "$tmp/types.go" > "$wt/$TYPES_FILE"
+
+if ! grep -q 'suspendDriftProbe' "$wt/$TYPES_FILE" || ! grep -q 'DriftProbe:' "$wt/$TYPES_FILE"; then
+  echo "✗ probe edit did not apply to $TYPES_FILE" >&2
+  exit 1
+fi
+
+git -C "$wt" -c user.name=drift-probe -c user.email=drift-probe@invalid \
+  commit -q --no-gpg-sign -am "drift probe"
+
+# Regeneration itself must succeed, so the failure below is the drift diff
+# and not a broken toolchain.
+(cd "$wt" && make generate manifests && make tidy)
+if git -C "$wt" diff --exit-code; then
+  echo "✗ gate passed on a stale types edit" >&2
+  exit 1
+fi
+echo "✓ gate failed on a stale types edit"
+
+echo
+echo "== Case 2: clean checkout (expect PASS)"
+
+git -C "$wt" reset -q --hard HEAD~1
+git -C "$wt" clean -fdq
+
+if ! gate "$wt"; then
+  echo "✗ gate failed on a clean checkout" >&2
+  exit 1
+fi
+echo "✓ gate passed on a clean checkout"
diff --git a/specs/013-expand-test-coverage/coverage-gaps.md b/specs/013-expand-test-coverage/coverage-gaps.md
index fbf685c0d..75e557132 100644
--- a/specs/013-expand-test-coverage/coverage-gaps.md
+++ b/specs/013-expand-test-coverage/coverage-gaps.md
@@ -1,7 +1,7 @@
 # Coverage Gap Record
 
-**Summary**: 2/24 closed · 0 closed unproven · 2 in progress · 19 open · 1 unit-only by design
-**Last updated**: 2026-10-11
+**Summary**: 3/24 closed · 0 closed unproven · 2 in progress · 18 open · 1 unit-only by design
+**Last updated**: 2026-10-12
 
 | ID | Category | Gap | Story | FR | Priority | Status | Evidence | Notes |
 |---|---|---|---|---|---|---|---|---|
@@ -9,7 +9,7 @@
 | G-02 | static | container image scan gate | US1 | FR-001 | P1 | open |  |  |
 | G-03 | static | Dockerfile lint gate | US1 | FR-001 | P1 | open |  |  |
 | G-04 | static | dependency-review gate | US1 | FR-001 | P1 | open |  |  |
-| G-05 | static | codegen / tidy drift gate | US1 | FR-001 | P1 | open |  |  |
+| G-05 | static | codegen / tidy drift gate | US1 | FR-001 | P1 | closed | `codegen drift` https://github.com/GameplanePanel/Gameplane/actions/runs/38189397259 | First run on #672 found no drift; the proof shows the job fails on injected drift. |
 | G-06 | static | submodule pointer freshness gate | US1 | FR-001 | P1 | open |  |  |
 | G-07 | e2e-dashboard | live: notification webhook config | US2 | FR-002 | P1 | open |  |  |
 | G-08 | e2e-dashboard | live: user create + role assignment | US2 | FR-002 | P1 | open |  |  |
diff --git a/specs/013-expand-test-coverage/tasks.md b/specs/013-expand-test-coverage/tasks.md
index 4b8252f39..b0a7d5cf6 100644
--- a/specs/013-expand-test-coverage/tasks.md
+++ b/specs/013-expand-test-coverage/tasks.md
@@ -105,19 +105,20 @@ description: "Task list for 013-expand-test-coverage"
 
 ### G5 codegen drift: PR `ci: codegen drift gate`
 
-- [ ] T012 [P] [US1] Write `hack/check-codegen-drift_test.sh`. In a `git worktree add` temp checkout it:
+- [X] T012 [P] [US1] Write `hack/check-codegen-drift_test.sh`. In a `git worktree add` temp checkout it:
   1. Appends a doc comment to a field in `operator/api/v1alpha1/gameserver_types.go`, edits the struct tag on that field, runs `make generate manifests && make tidy && git diff --exit-code`, and expects a non-zero exit.
   2. Resets the checkout, reruns the same command, and expects zero.
 
   It removes the worktree on exit.
-- [ ] T013 [US1] Add a `codegen-drift` job named `codegen drift` to `.github/workflows/ci.yaml`. Settings:
+- [X] T013 [US1] Add a `codegen-drift` job named `codegen drift` to `.github/workflows/ci.yaml`. Settings:
   - `needs: [changes]`
   - `if: needs.changes.outputs.codegen == 'true' || github.event_name == 'push'`
   - setup: `actions/checkout`, `./.github/actions/go-cache`, `azure/setup-helm`
   - steps: `make generate manifests`, then `make tidy`, then `git diff --exit-code`, then `./hack/check-codegen-drift_test.sh`
 
   Register the job in `report`. Depends on T007 and T012.
-- [ ] T014 [US1] If the first CI run of T013 shows drift, commit the regenerated files the job printed: deepcopy, `operator/config/**`, chart CRDs, `go.mod`/`go.sum`. Flip gap row G-05 with the job name and run link.
+- [X] T014 [US1] If the first CI run of T013 shows drift, commit the regenerated files the job printed: deepcopy, `operator/config/**`, chart CRDs, `go.mod`/`go.sum`. Flip gap row G-05 with the job name and run link.
+  *Implementation note (2026-10-12)*: the first run of `codegen drift` (run 38189397259) found no drift, so there was nothing to commit.
 
 ### G1 govulncheck: PR `ci: go vulnerability gate`