diff --git a/tools/skill_manager_tool.py b/tools/skill_manager_tool.py
index eaf30dd41a..debea52642 100644
--- a/tools/skill_manager_tool.py
+++ b/tools/skill_manager_tool.py
@@ -374,6 +374,23 @@ def _background_review_write_guard(
                     f"skill '{name}'."
                 ),
             }
+        # Manually authored skills (created_by != "agent") are off-limits
+        # to autonomous curation. This prevents the LLM consolidation pass
+        # from archiving skills the user placed manually (e.g. via URL
+        # install or direct SKILL.md authoring), which lack the
+        # `created_by: "agent"` marker.
+        usage_data = skill_usage.load_usage()
+        usage_rec = usage_data.get(name)
+        if isinstance(usage_rec, dict) and not skill_usage._is_curator_managed_record(usage_rec):
+            return {
+                "success": False,
+                "error": (
+                    f"Refusing background curator {action} for skill "
+                    f"'{name}': the skill records show it is not agent-created "
+                    f"(created_by={usage_rec.get('created_by')!r}). Manually authored "
+                    f"skills are off-limits to autonomous curation."
+                ),
+            }
     except Exception:
         logger.debug("owned skill guard lookup failed for %s", name, exc_info=True)
     return None