diff --git a/src/cleveragents/cli/commands/plan.py b/src/cleveragents/cli/commands/plan.py
index 13c2f78ad..9268bddf6 100644
--- a/src/cleveragents/cli/commands/plan.py
+++ b/src/cleveragents/cli/commands/plan.py
@@ -1345,6 +1345,70 @@ def _get_lifecycle_service():
     return container.plan_lifecycle_service()
 
 
+def _cleanup_stale_sandbox(repo_path: str, plan_id: str) -> None:
+    """Remove a stale worktree branch and directory for a plan.
+
+    If a previous execute left behind a worktree branch
+    ``cleveragents/plan-<plan_id>``, this function removes the worktree
+    directory and deletes the branch so that a fresh sandbox can be
+    created.  Silently does nothing if no stale branch exists.
+    """
+    import subprocess
+
+    branch_name = f"cleveragents/plan-{plan_id}"
+
+    # Check if the branch exists
+    check = subprocess.run(
+        ["git", "rev-parse", "--verify", f"refs/heads/{branch_name}"],
+        cwd=repo_path,
+        capture_output=True,
+        check=False,
+        timeout=10,
+    )
+    if check.returncode != 0:
+        return  # No stale branch — nothing to clean
+
+    # Find and remove the worktree directory
+    wt_list = subprocess.run(
+        ["git", "worktree", "list", "--porcelain"],
+        cwd=repo_path,
+        capture_output=True,
+        text=True,
+        check=False,
+        timeout=10,
+    )
+    for wt_block in wt_list.stdout.split("\n\n"):
+        if f"branch refs/heads/{branch_name}" in wt_block:
+            for line in wt_block.splitlines():
+                if line.startswith("worktree "):
+                    wt_path = line.split("worktree ", 1)[1]
+                    subprocess.run(
+                        ["git", "worktree", "remove", "--force", wt_path],
+                        cwd=repo_path,
+                        capture_output=True,
+                        check=False,
+                        timeout=10,
+                    )
+
+    # Delete the branch
+    subprocess.run(
+        ["git", "branch", "-D", branch_name],
+        cwd=repo_path,
+        capture_output=True,
+        check=False,
+        timeout=10,
+    )
+
+    # Prune stale worktree references
+    subprocess.run(
+        ["git", "worktree", "prune"],
+        cwd=repo_path,
+        capture_output=True,
+        check=False,
+        timeout=10,
+    )
+
+
 def _create_sandbox_for_plan(
     plan_id: str,
     service: PlanLifecycleService,
@@ -1387,6 +1451,10 @@ def _create_sandbox_for_plan(
                 and resource.location
                 and os.path.isdir(os.path.join(resource.location, ".git"))
             ):
+                _cleanup_stale_sandbox(
+                    resource.location,
+                    plan_id,
+                )
                 sandbox = GitWorktreeSandbox(
                     resource_id=resource.resource_id,
                     original_path=resource.location,