diff --git a/cmd/odek/subagent.go b/cmd/odek/subagent.go
index dfabea5..fa5aeb0 100644
--- a/cmd/odek/subagent.go
+++ b/cmd/odek/subagent.go
@@ -617,7 +617,12 @@ func subagentCmd(args []string) error {
 		// is workspace-relative infrastructure (an ordinary local_write for
 		// the child's file tools). Inside the fence it would be neutralized
 		// for untrusted tasks, silently disabling artifacts exactly where
-		// they matter.
+		// they matter. The workspace is also self-healed here: stale
+		// sibling staging from crashed runs is swept at start.
+		if cwd, err := os.Getwd(); err == nil {
+			ensureStagingRoot(cwd)
+			sweepStagingOrphans(cwd, taskTaskID, stagingSweepMaxAge)
+		}
 		prompt += childArtifactNote(".odek-artifacts/" + taskTaskID)
 	}
 
@@ -852,6 +857,9 @@ func subagentCmd(args []string) error {
 				flags = append(flags, "[artifact] staging relocation failed: "+err.Error())
 			}
 		}
+		// Re-create the staging root with its self-gitignore (relocation
+		// removed the whole subtree, root included).
+		ensureStagingRoot(cwd)
 		refs, scanFlags := scanArtifacts(taskArtifactRoot, maxArtifactTaskBudget)
 		result.Artifacts = refs
 		flags = append(flags, scanFlags...)
diff --git a/cmd/odek/subagent_artifact_registry.go b/cmd/odek/subagent_artifact_registry.go
index c9ac159..4f2ccfd 100644
--- a/cmd/odek/subagent_artifact_registry.go
+++ b/cmd/odek/subagent_artifact_registry.go
@@ -261,3 +261,52 @@ func copyFileContents(src, dst string) error {
 	}
 	return out.Close()
 }
+
+const (
+	// stagingSweepMaxAge matches the janitor backstop retention: orphaned
+	// staging subtrees (crash/kill before relocation) older than this are
+	// swept by the next artifact-bearing run in the same workspace.
+	stagingSweepMaxAge = 24 * time.Hour
+	// stagingGitignore keeps staged deliverables out of the user's
+	// repository — the staging root lives INSIDE the workspace.
+	stagingGitignore = "*\n!.gitignore\n"
+)
+
+// ensureStagingRoot creates the staging root (0700) and drops a
+// self-gitignore so staged deliverables never land in the user's
+// repository. Idempotent; best-effort.
+func ensureStagingRoot(cwd string) {
+	root := filepath.Join(cwd, stagingDirName)
+	if err := os.MkdirAll(root, 0o700); err != nil {
+		return
+	}
+	_ = os.WriteFile(filepath.Join(root, ".gitignore"), []byte(stagingGitignore), 0o600)
+}
+
+// sweepStagingOrphans removes sibling staging task dirs older than maxAge —
+// crash/kill orphans the runner could not clean (the janitor only knows
+// ~/.odek, not user workspaces). The current task's dir is never touched,
+// and fresh siblings may belong to in-flight parallel tasks in the same
+// workspace. Returns the number of subtrees removed.
+func sweepStagingOrphans(cwd, currentTaskID string, maxAge time.Duration) int {
+	root := filepath.Join(cwd, stagingDirName)
+	entries, err := os.ReadDir(root)
+	if err != nil {
+		return 0
+	}
+	cutoff := time.Now().Add(-maxAge)
+	removed := 0
+	for _, e := range entries {
+		if !e.IsDir() || e.Name() == currentTaskID {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil || info.ModTime().After(cutoff) {
+			continue
+		}
+		if os.RemoveAll(filepath.Join(root, e.Name())) == nil {
+			removed++
+		}
+	}
+	return removed
+}
diff --git a/cmd/odek/subagent_staging_sweep_test.go b/cmd/odek/subagent_staging_sweep_test.go
new file mode 100644
index 0000000..fb1c432
--- /dev/null
+++ b/cmd/odek/subagent_staging_sweep_test.go
@@ -0,0 +1,101 @@
+package main
+
+// TDD RED phase — staging-dir hygiene (fix/staging-sweep). The workspace
+// staging root (.odek-artifacts/) had three gaps: crash-orphans with
+// content were never cleaned (the janitor only knows ~/.odek), the empty
+// parent persisted, and staged deliverables were visible to the user's
+// git. Every artifact-bearing child run now self-heals its workspace.
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestEnsureStagingRoot_Gitignore(t *testing.T) {
+	cwd := t.TempDir()
+	ensureStagingRoot(cwd)
+
+	gitignore := filepath.Join(cwd, stagingDirName, ".gitignore")
+	b, err := os.ReadFile(gitignore)
+	if err != nil {
+		t.Fatalf("staging root must carry a self-gitignore: %v", err)
+	}
+	if string(b) != "*\n!.gitignore\n" {
+		t.Errorf("gitignore content = %q, want %q", b, "*\n!.gitignore\n")
+	}
+	// Idempotent: a second call must not fail or duplicate.
+	ensureStagingRoot(cwd)
+	b2, _ := os.ReadFile(gitignore)
+	if string(b2) != "*\n!.gitignore\n" {
+		t.Errorf("second ensure must keep content stable: %q", b2)
+	}
+}
+
+func TestSweepStagingOrphans_AgedRemovedOthersKept(t *testing.T) {
+	cwd := t.TempDir()
+	root := filepath.Join(cwd, stagingDirName)
+	aged := filepath.Join(root, "task-dead")
+	fresh := filepath.Join(root, "task-live")
+	current := "task-current"
+	for _, d := range []string{filepath.Join(aged, "t"), fresh} {
+		if err := os.MkdirAll(d, 0o700); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := os.WriteFile(filepath.Join(aged, "t", "big.bin"), []byte("orphan"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	old := time.Now().Add(-48 * time.Hour)
+	if err := os.Chtimes(aged, old, old); err != nil {
+		t.Fatal(err)
+	}
+
+	removed := sweepStagingOrphans(cwd, current, 24*time.Hour)
+	if removed != 1 {
+		t.Fatalf("want 1 orphan removed, got %d", removed)
+	}
+	if _, err := os.Stat(aged); !os.IsNotExist(err) {
+		t.Error("aged orphan must be removed")
+	}
+	if _, err := os.Stat(fresh); err != nil {
+		t.Error("fresh sibling must be kept (may be an in-flight parallel task)")
+	}
+}
+
+func TestSweepStagingOrphans_MissingRootNoop(t *testing.T) {
+	if n := sweepStagingOrphans(t.TempDir(), "task-x", 24*time.Hour); n != 0 {
+		t.Errorf("missing staging root must be a no-op, got %d", n)
+	}
+}
+
+func TestStagingRoot_TidiedAfterRelocation(t *testing.T) {
+	// After relocation the staging root keeps only the self-gitignore —
+	// no empty task dirs, no deliverable residue.
+	root := t.TempDir()
+	staging := filepath.Join(root, stagingDirName, "task-1")
+	if err := os.MkdirAll(staging, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	writeArtifactFile(t, staging, "report.md", "content")
+	canonical := filepath.Join(root, "canonical")
+
+	if _, err := relocateStagingArtifacts(staging, canonical); err != nil {
+		t.Fatal(err)
+	}
+	ensureStagingRoot(root)
+
+	entries, err := os.ReadDir(filepath.Join(root, stagingDirName))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, e := range entries {
+		if e.IsDir() {
+			t.Errorf("task dir %q must be gone after relocation", e.Name())
+		}
+	}
+	if _, err := os.Stat(filepath.Join(canonical, "report.md")); err != nil {
+		t.Errorf("relocated artifact missing: %v", err)
+	}
+}