diff --git a/mcp_server.py b/mcp_server.py
index f2918f8..692c47f 100644
--- a/mcp_server.py
+++ b/mcp_server.py
@@ -225,6 +225,7 @@ def update_ticket(
     status:         str = "",
     type:           str = "",
     user:           str = "",
+    startup_script: str = "",
     parent_id:      int = -1,
     effort:         int = -1,
     environment_id: int = -1,
@@ -240,6 +241,10 @@ def update_ticket(
         status:         open, ongoing, completed, abandoned.
         type:           feature, bug, chore, project.
         user:           kevin or claude.
+        startup_script: Override the auto-generated claude startup command.
+                        Pass the full claude "..." --allowedTools "..." string.
+                        When omitted but title/description/type changes, the
+                        script is regenerated automatically.
         parent_id:      Set parent ticket ID; pass 0 to clear the parent.
                         Omit (default -1) to leave unchanged.
         effort:         Effort rating 1–10; pass 0 to clear it.
@@ -259,11 +264,16 @@ def update_ticket(
         body["effort"] = effort if effort > 0 else None
     if environment_id >= 0:
         body["environment_id"] = environment_id if environment_id > 0 else None
-    if not body:
+    if not body and not startup_script:
         raise ValueError("Provide at least one field to update")
     with _client() as c:
-        ticket = _check(c.patch(f"/api/tickets/{ticket_id}", json=body))
-        if title or description or type:
+        if body:
+            ticket = _check(c.patch(f"/api/tickets/{ticket_id}", json=body))
+        else:
+            ticket = _check(c.get(f"/api/tickets/{ticket_id}"))
+        if startup_script:
+            ticket = _check(c.patch(f"/api/tickets/{ticket_id}", json={"startup_script": startup_script}))
+        elif title or description or type:
             script = _generate_startup_script(
                 ticket["id"], ticket["human_id"],
                 ticket["title"], ticket["description"], ticket["type"],