[Sahil-u07]

What's wrong

The Shell Shock challenge (shell_shock.yaml) sets min_prior_tool_calls: 1, so a one-shot reverse shell shouldn't complete it. The player is supposed to warm the agent up with a safe SystemUtils call first. Right now that gate doesn't hold.

CTFEventProcessor._process_event stores the event in ctf_events (_store_ctf_event) before it runs the detectors. By the time RCEDetector._count_prior_tool_calls queries the table, the execute_script call it's checking is already there, and it gets counted as its own prior call. So a single malicious call is enough.

Fix

Exclude the current event from the count by its external_event_id. The id is built the same way _store_ctf_event builds it, and I left a comment pointing there so the two don't drift apart.

Tests

New file tests/unit/ctf/test_rce_multi_turn_gate.py. Both tests store events through the real _store_ctf_event before calling the detector, so they follow the same order the processor uses:

• a single reverse-shell call with nothing before it is not detected
• the same call after one run_diagnostics call is still detected

On main the first test fails because the detector returns detected=True. With the fix both pass.

# main
FAILED tests/unit/ctf/test_rce_multi_turn_gate.py::test_single_shot_rce_does_not_pass_gate
1 failed, 1 passed

# this branch
2 passed

Before (on main):

After:

The full suite gives the same 4 failures I get on main (3 in test_specialized_agents.py, 1 in test_database_provider.py), nothing new.

Related: #300 is about the same function when workflow_id is missing. That's a separate problem and I haven't touched it here.