docs(routines): clarify automatic workspace variables

server/src/services/routines.ts

@@ -282,6 +282,8 @@ function resolveRoutineVariableValues(
   const missing: string[] = [];
 
   for (const variable of variables) {
+    // Workspace-derived automatic values are authoritative for variables that
+    // Paperclip manages from execution context, so callers cannot override them.
     const candidate = automaticVariables[variable.name] !== undefined
       ? automaticVariables[variable.name]
       : provided[variable.name] !== undefined