hardening: fix command-injection in agent check_command + add double-launch guard

- check_agent() custom check_type: replace subprocess shell=True with
  shlex.split + shell=False (prevents agent-registry config from injecting
  arbitrary shell). Verified malicious '; touch' no longer executes.
- Add startup port guard in main: probe API port before uvicorn.run;
  exit 1 with clear message if already bound (stops the double-instance
  collision that caused phantom 'register does not persist' bugs).
- start_terminal_server (8082): pre-bind probe + try/except so a taken
  port logs a warning instead of crashing the whole process.

brain/recent-decisions.md

@@ -13,8 +13,13 @@
 - New skills added: firebase-* (10), notion-knowledge-capture, xcode-project-setup, audit-test-plugin, test-plugin.
 - `.gitignore` extended to exclude runtime artifacts (pid, graphify-out, logs).
 - VERIFIED live: server on :8081, all new endpoints return 200; register/unregister persists correctly.
-- CAVEAT (not yet fixed): agent `check_command` runs via `subprocess.run(..., shell=True)` — command-injection risk if a malicious agent config is registered. Local-admin-only exposure; flag for later hardening.
-- CAVEAT: avoid running two `server.py` instances on the same port — registration on one won't show in reads served by the other.
+- CAVEAT (FIXED 2026-07-25): agent `check_command` previously ran via `subprocess.run(..., shell=True)` — command-injection risk. Now uses `shlex.split` + `shell=False`. Verified: malicious `"; touch /tmp/PWNED"` no longer executes.
+- CAVEAT (FIXED 2026-07-25): running two `server.py` on same port caused phantom "register doesn't persist" + 8082 bind crash. Added startup port guard (exits cleanly with message) + terminal websocket now binds gracefully instead of crashing. Verified: 2nd instance bails with exit 1.
+
+## 2026-07-25 — Security & ops hardening (commit pending)
+- Fixed command-injection in `check_agent()` custom check_type: `shell=True` → `shlex.split` + `shell=False`.
+- Added double-launch guard in `main`: probe API port (8081) before `uvicorn.run`; exit 1 with clear message if already bound.
+- Made `start_terminal_server` (8082) fail gracefully — pre-bind probe + try/except, logs warning instead of crashing the process.
 
 ## Archived (older than 30 days)
 

server.py

@@ -2271,6 +2271,8 @@ import signal
 # redundant terminal implementations.
 
 
+
+
 # ─── Routes: Dashboard Static Files ──────────────────────────────
 
 dashboard_dir = BASE_DIR / "dashboard"
@@ -2385,6 +2387,7 @@ def favicon_svg():
 # ─── Main ─────────────────────────────────────────────────────────
 
 if __name__ == "__main__":
+    import argparse
     import socket
 
     import uvicorn