.agents/skills/lib_py/agents/__main__.py

@@ -1,6 +1,6 @@
 # __main__.py — CLI bridge for lib_py.agents facts and resolution (N4)
 
-import os, sys, json, shlex
+import os, sys, json, shlex, time
 from lib_py.agents.registry import get_adapter, own_key, agent_of_row
 
 # `purge auto` probes adapters in this order; opencode last because its
@@ -151,6 +151,38 @@ def main():
         print(json.dumps({"agent": name, "purged": purged, "residual": residual, "in_use": False}))
         sys.exit(0)
 
+    elif cmd == 'in-use':
+        # in-use <agent> <uuid> [workspace] [--wait <sec>]  (Issue #31)
+        # The purge CLI's own in-use verdict, for stop_session.sh to ask
+        # before it purges. Re-checks every 0.25 s for up to --wait seconds.
+        # Prints {"agent", "in_use"}. Exit 0 free; 4 still in use; 1 bad args.
+        args = sys.argv[2:]
+        wait = 0.0
+        if '--wait' in args:
+            i = args.index('--wait')
+            try:
+                wait = float(args[i + 1])
+            except (IndexError, ValueError):
+                print("ERROR: --wait requires seconds", file=sys.stderr)
+                sys.exit(1)
+            del args[i:i + 2]
+        agent_name = args[0] if args else ''
+        uuid = args[1] if len(args) > 1 else ''
+        workspace = args[2] if len(args) > 2 and args[2] else os.getcwd()
+        adapter = get_adapter(agent_name)
+        if not adapter or not uuid:
+            print("ERROR: in-use requires <agent> <uuid>", file=sys.stderr)
+            sys.exit(1)
+        from lib_py.agents.base import DiscoveryContext
+        ctx = DiscoveryContext(workspace, agent_name)
+        deadline = time.monotonic() + wait
+        in_use = adapter.conversation_in_use(uuid, ctx)
+        while in_use and time.monotonic() < deadline:
+            time.sleep(0.25)
+            in_use = adapter.conversation_in_use(uuid, ctx)
+        print(json.dumps({"agent": agent_name, "in_use": in_use}))
+        sys.exit(4 if in_use else 0)
+
     else:
         print(f"ERROR: Unknown CLI command {cmd!r}", file=sys.stderr)
         sys.exit(1)

.agents/skills/multi-agent-mux-stop/scripts/stop_session.sh

@@ -282,6 +282,23 @@ if [ "$PURGE" = "1" ] && [ "$HERDR_ALIVE" = "1" ]; then
   fi
 fi
 
+# Purge process gate (Issue #31): a closed herdr session is not an exited
+# agent - the process may still be shutting down, or may have outlived a dead
+# herdr ("herdr already dead" above runs no gate at all). The purge asks the
+# adapter's own in-use verdict, the one the purge CLI uses, outside the
+# registry lock. Any answer but "free" (0) keeps everything.
+if [ "$PURGE" = "1" ] && [ -n "$PURGE_UUID" ]; then
+  inuse_rc=0
+  "$(_delegate_py_bin)" -m lib_py.agents in-use "$AGENT" "$PURGE_UUID" "$TARGET_CWD" --wait 5 >/dev/null || inuse_rc=$?
+  if [ "$inuse_rc" != "0" ]; then
+    echo "ERROR: conversation $PURGE_UUID is still held by a live agent process (rc=$inuse_rc)." >&2
+    echo "  Refusing purge — records preserved (no state was modified)." >&2
+    echo "  For claude, see the session files naming it under ~/.claude/sessions/." >&2
+    delegate_publish_event "$DELEGATE_JOB_ID" cancelled "purge aborted: conversation still in use; no state was modified" "$DELEGATE_JOB_TOKEN" "$DELEGATE_JOB_ATTEMPT"
+    exit 4
+  fi
+fi
+
 # INVARIANT: Terminal events for a job must be published AFTER atomic_dump_yaml updates the session status
 atomic_dump_yaml "$AGENT_SESSIONS_YAML" \
   SESSION_NAME="$SESSION_NAME" AGENT="$AGENT" PURGE="$PURGE" \