diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 1e8be8f62..6a4d51f15 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -24,6 +24,11 @@ env:
 # Pipeline (sequential, fail-fast):
 #   go-test → e2e-test → build-and-publish → deploy → publish-badges
 #   PRs stop after build-and-publish (no GHCR push). Master continues to deploy + badges.
+#
+# Fork guard: everything with an external side effect (GHCR login/push, release
+# upload, staging deploy, badge commits) additionally requires
+# github.repository == 'Kpa-clawbot/CoreScope'. On a fork (e.g. dborup/CoreScope)
+# only the tests, the local image build and CI artifact uploads run.
 
 jobs:
   # ───────────────────────────────────────────────────────────────
@@ -605,15 +610,15 @@ jobs:
           echo "Built Go staging image ✅"
 
       - name: Set up Docker Buildx
-        if: github.event_name == 'push'
+        if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
         uses: docker/setup-buildx-action@v3
 
       - name: Set up QEMU (arm64 runtime stage)
-        if: github.event_name == 'push'
+        if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
         uses: docker/setup-qemu-action@v3
 
       - name: Log in to GHCR
-        if: github.event_name == 'push'
+        if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
         uses: docker/login-action@v3
         with:
           registry: ghcr.io
@@ -621,7 +626,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Extract Docker metadata
-        if: github.event_name == 'push'
+        if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
         id: docker-meta
         uses: docker/metadata-action@v5
         with:
@@ -634,7 +639,7 @@ jobs:
             type=edge,branch=master
 
       - name: Build and push to GHCR
-        if: github.event_name == 'push'
+        if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
         uses: docker/build-push-action@v6
         with:
           context: .
@@ -654,7 +659,8 @@ jobs:
   # ───────────────────────────────────────────────────────────────
   release-artifacts:
     name: "📦 Release Artifacts"
-    if: startsWith(github.ref, 'refs/tags/v')
+    # Fork guard: release uploads only on the upstream repository.
+    if: startsWith(github.ref, 'refs/tags/v') && github.repository == 'Kpa-clawbot/CoreScope'
     needs: [go-test]
     runs-on: ubuntu-latest
     permissions:
@@ -690,9 +696,12 @@ jobs:
   # ───────────────────────────────────────────────────────────────
   deploy:
     name: "🚀 Deploy Staging"
+    # Fork guard (last clause): never scheduled on a fork, so no fork run can
+    # reach the self-hosted staging runner.
     if: |
       (github.event_name == 'push' || github.event_name == 'workflow_dispatch')
       && github.ref == 'refs/heads/master'
+      && github.repository == 'Kpa-clawbot/CoreScope'
     needs: [build-and-publish]
     runs-on: [self-hosted, meshcore-runner-2]
     steps:
@@ -780,7 +789,8 @@ jobs:
   # ───────────────────────────────────────────────────────────────
   publish:
     name: "📝 Publish Badges & Summary"
-    if: github.event_name == 'push'
+    # Fork guard: badge files are committed to master only on the upstream repository.
+    if: github.event_name == 'push' && github.repository == 'Kpa-clawbot/CoreScope'
     needs: [deploy]
     runs-on: ubuntu-latest
     steps:
diff --git a/.github/workflows/release-fast-path.yml b/.github/workflows/release-fast-path.yml
index 86abaf7f2..759f418de 100644
--- a/.github/workflows/release-fast-path.yml
+++ b/.github/workflows/release-fast-path.yml
@@ -25,6 +25,8 @@ concurrency:
 jobs:
   retag-or-fallback:
     name: "🏷️ Re-tag :edge → :vX.Y.Z (fast) or dispatch deploy.yml (fallback)"
+    # Fork guard: GHCR re-tag and the deploy.yml dispatch only on the upstream repository.
+    if: github.repository == 'Kpa-clawbot/CoreScope'
     runs-on: ubuntu-latest
     steps:
       - name: Log in to GHCR
diff --git a/cmd/server/fork_guard_workflow_test.go b/cmd/server/fork_guard_workflow_test.go
new file mode 100644
index 000000000..7e16ef383
--- /dev/null
+++ b/cmd/server/fork_guard_workflow_test.go
@@ -0,0 +1,130 @@
+// Tests for the fork side-effect guards in the CI workflows.
+//
+// These tests gate workflow config (not Go code) by reading the YAML as text,
+// following the same "config gate" pattern as release_fast_path_workflow_test.go.
+//
+// The workflows are shared with the upstream repository Kpa-clawbot/CoreScope,
+// where they publish images and releases, deploy staging on a self-hosted
+// runner and commit badge files. On a fork those side effects must never run,
+// while ordinary CI (tests, the local image build, CI artifact uploads) keeps
+// running. Every guard is ANDed with the job's or step's existing condition, so
+// upstream behaviour is unchanged.
+package main
+
+import (
+	"os"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+const upstreamRepoGuard = "github.repository == 'Kpa-clawbot/CoreScope'"
+
+func readWorkflow(t *testing.T, rel string) string {
+	t.Helper()
+	raw, err := os.ReadFile(rel)
+	if err != nil {
+		t.Fatalf("read %s: %v", rel, err)
+	}
+	return string(raw)
+}
+
+// workflowJob returns the text of a top-level job (two-space indented key)
+// up to the next top-level job.
+func workflowJob(t *testing.T, src, job string) string {
+	t.Helper()
+	re := regexp.MustCompile(`(?ms)^  ` + regexp.QuoteMeta(job) + `:[ \t]*\n(.*?)(?:^  [a-zA-Z0-9_-]+:[ \t]*\n|\z)`)
+	m := re.FindStringSubmatch(src)
+	if m == nil {
+		t.Fatalf("job %q not found", job)
+	}
+	return m[1]
+}
+
+// jobIf returns the job-level `if:` expression (single or multi-line), or "".
+func jobIf(job string) string {
+	m := regexp.MustCompile(`(?ms)^    if:(.*?)^    [a-zA-Z-]+:`).FindStringSubmatch(job)
+	if m == nil {
+		return ""
+	}
+	return m[1]
+}
+
+func TestForkGuardOnSideEffectJobs(t *testing.T) {
+	deploy := readWorkflow(t, deployWorkflowRel)
+	fastPath := readWorkflow(t, fastPathWorkflowRel)
+
+	cases := []struct {
+		file, src, job string
+		keep           []string // pre-existing conditions that must survive
+	}{
+		{"deploy.yml", deploy, "release-artifacts", []string{"startsWith(github.ref, 'refs/tags/v')"}},
+		{"deploy.yml", deploy, "deploy", []string{
+			"(github.event_name == 'push' || github.event_name == 'workflow_dispatch')",
+			"github.ref == 'refs/heads/master'",
+		}},
+		{"deploy.yml", deploy, "publish", []string{"github.event_name == 'push'"}},
+		{"release-fast-path.yml", fastPath, "retag-or-fallback", nil},
+	}
+	for _, c := range cases {
+		cond := jobIf(workflowJob(t, c.src, c.job))
+		if !strings.Contains(cond, upstreamRepoGuard) {
+			t.Errorf("%s job %q: job-level if must contain %q so it never runs on a fork; got %q", c.file, c.job, upstreamRepoGuard, cond)
+		}
+		for _, k := range c.keep {
+			if !strings.Contains(cond, k) {
+				t.Errorf("%s job %q: existing condition %q must be kept (guard is ANDed, not a replacement); got %q", c.file, c.job, k, cond)
+			}
+		}
+	}
+}
+
+func TestForkGuardOnPublishSteps(t *testing.T) {
+	job := workflowJob(t, readWorkflow(t, deployWorkflowRel), "build-and-publish")
+	if cond := jobIf(job); cond != "" {
+		t.Errorf("build-and-publish must stay unconditional at job level so the local image build still validates on forks; got if %q", cond)
+	}
+	steps := regexp.MustCompile(`(?m)^      - name:`).Split(job, -1)[1:]
+	publishMarkers := []string{"docker/setup-buildx-action", "docker/setup-qemu-action", "docker/login-action", "docker/metadata-action", "docker/build-push-action"}
+	guarded, sawLocalBuild := 0, false
+	for _, step := range steps {
+		ifLine := regexp.MustCompile(`(?m)^        if:(.*)$`).FindStringSubmatch(step)
+		cond := ""
+		if ifLine != nil {
+			cond = ifLine[1]
+		}
+		if strings.Contains(step, "Build Go Docker image (local staging)") {
+			sawLocalBuild = true
+			if strings.Contains(cond, "github.repository") {
+				t.Errorf("local staging image build must not be repository-guarded (it is fork-safe validation); got if %q", cond)
+			}
+		}
+		for _, marker := range publishMarkers {
+			if strings.Contains(step, marker) {
+				if !strings.Contains(cond, upstreamRepoGuard) || !strings.Contains(cond, "github.event_name == 'push'") {
+					t.Errorf("publish step using %s must require both push and %q; got if %q", marker, upstreamRepoGuard, cond)
+				}
+				guarded++
+			}
+		}
+	}
+	if !sawLocalBuild {
+		t.Errorf("build-and-publish: local staging image build step not found")
+	}
+	if guarded != len(publishMarkers) {
+		t.Errorf("build-and-publish: expected %d guarded publish steps, found %d", len(publishMarkers), guarded)
+	}
+}
+
+func TestForkGuardLeavesTestJobsRunning(t *testing.T) {
+	deploy := readWorkflow(t, deployWorkflowRel)
+	for _, name := range []string{"go-test", "e2e-test"} {
+		job := workflowJob(t, deploy, name)
+		if cond := jobIf(job); cond != "" {
+			t.Errorf("%s must not gain a job-level condition; got %q", name, cond)
+		}
+		if strings.Contains(job, "github.repository") {
+			t.Errorf("%s must not be repository-guarded: tests and CI artifact uploads run on forks too", name)
+		}
+	}
+}