Writing node source, installing modules and any flow save that adds, retypes or repoints a code node (Function, Command), edits a Command node's settings or changes a node's resources.env now answer 403 for everyone but a superuser. MCP tools and the assistant reach the same routes, so they inherit the gate. Node types report runs_code. The editor shows code read-only with a note, disables a Command node's settings, leaves code nodes and reusable nodes out of the palette and paste, and the Modules page offers no install. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013GAeg4Jo6xjZzjwy9QDWMQ