guard --session <uuid> fails with 'Could not detect current session' on every invocation

[bdwelle]

Bug

When cozempic guard --daemon is invoked with an explicit --session <uuid> flag (as the SessionStart hook does via ${SESSION_ID:+--session $SESSION_ID}), the daemon starts, immediately prints ERROR: Could not detect current session, and exits — leaving a stale PID file behind and providing zero protection.

Note: I had Claude write this issue for me. I don't really understand enough about what's going on to file it myself, just that I got caught again this morning with the "Extra usage is required for long context requests" warning and asked omp/Claude to diagnose and fix it.

Environment

• cozempic 1.6.18
• macOS 26.1 Tahoe (Mac Mini M4)
• Oh My Pi coding harness (omp/14.1.0) — hooks fire correctly but guard always dies

Reproduction

The cozempic init-generated SessionStart hook runs:

cozempic guard --daemon --session <uuid> --cwd /path/to/project

This fails every time. Log output:

--- Guard daemon started at 2026-04-11T08:48:28 ---
CWD: /Users/bdwelle/lib/foilfinder
CMD: python3 -m cozempic.cli guard --cwd /Users/bdwelle/lib/foilfinder --threshold 50.0 --interval 30 -rx standard --session <uuid>

  ERROR: Could not detect current session.

Contrast: working invocation

Running without --session from the same directory succeeds — the daemon auto-detects the correct session ID and starts the 4-tier guard:

cozempic guard --daemon --threshold 50 -rx standard --interval 30

4-tier guard protecting context (200K window):
  Soft  (25%): gentle prune, no reload
  Hard1 (55%): standard prune + reload
  Hard2 (80%): aggressive prune + reload
  Hard3 (90%): manual aggressive

Impact

The SessionStart hook is the entire auto-protection mechanism. When --session breaks the daemon, every session silently goes unguarded. In our case: 66 consecutive guard processes spawned across multiple days, all dead on arrival, all leaving stale PID files in /tmp.

Workaround

Remove the explicit --session injection from the hook — replace:

cozempic guard --daemon ${SESSION_ID:+--session $SESSION_ID}

with:

cozempic guard --daemon

Guard auto-detects the session correctly when left to its own devices.

Suggested fix

Either:

1. Fix guard --session <uuid> to resolve the session file path the same way auto-detection does, or
2. Have cozempic init not inject --session into the hook (auto-detection already works)