Module guard 

Shared guard-hook plumbing.

The harness-specific verdict shaping lives with each harness’s guard module (crate::adapters::<harness>::guard): the CLI handler reads the hook payload from stdin and the marker path from argv, and the harness guard calls [parse_tool_call] + decide to evaluate it. Both layers fail open — a malformed payload or unreadable marker yields “allow”, so the guard can never brick a session.

Functions

read_marker

Read and parse the guard marker. Missing or unparseable → None (the guard then allows everything — fail open).