Secure prompt debug filesystem writes

docs/integrations/promptkit.md

@@ -32,6 +32,8 @@ Promptkit receives the YAML data package as an inline input and returns structur
 When capture is enabled, its preparation artifact projects a provider endpoint
 to its scheme and host and retains only reviewed execution settings. Provider
 extras and URL user information, paths, queries, and fragments are omitted.
+Capture storage remains confined to the operator-selected debug root; an unsafe
+filesystem path causes the requested execution to fail.
 
 ## Comparison Execution
 

docs/operations.md

@@ -147,6 +147,9 @@ Preparation captures retain only the provider endpoint origin and reviewed
 execution settings. URL user information, paths, queries, fragments, and
 unrecognized provider parameters are omitted.
 
+Capture writes are confined to the requested root and fail if an unsafe
+filesystem component prevents secure artifact creation.
+
 If capture creation or writing fails, the affected run fails rather than
 silently continuing without the requested diagnostics.