feat(host-agent): add mcp-token CLI subcommand

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/device-host-agent/host_agent/cli.py

@@ -10,6 +10,7 @@ from host_agent.app import create_application
 from host_agent.config import load_host_agent_config
 from host_agent.instance_lock import InstanceAlreadyRunningError
 from host_agent.local_account import LocalAccountStore
+from host_agent.mcp_token import McpTokenStore
 
 
 class LocalAccountSetupError(RuntimeError):
@@ -20,8 +21,16 @@ def main(argv: Sequence[str] | None = None) -> None:
     parser = argparse.ArgumentParser(description="Run the Device Host Agent")
     subparsers = parser.add_subparsers(dest="command")
     subparsers.add_parser("setup", help="Create the local operator account")
+    subparsers.add_parser(
+        "mcp-token",
+        help="Print the MCP server bearer token (generating if missing)",
+    )
     args = parser.parse_args(argv)
 
+    if args.command == "mcp-token":
+        _print_mcp_token()
+        return
+
     try:
         if args.command == "setup":
             _run_setup()
@@ -54,6 +63,12 @@ def _run_setup() -> None:
     print(f"Local account '{account.username}' created.")
 
 
+def _print_mcp_token() -> None:
+    config = load_host_agent_config()
+    store = McpTokenStore(config.identity_path.parent / "host_mcp_token.json")
+    print(store.load_or_create().token)
+
+
 def _resolve_config_with_local_account():
     config = load_host_agent_config()
     store = LocalAccountStore(config.local_account_path)

apps/device-host-agent/tests/test_cli.py

@@ -146,3 +146,19 @@ def test_duplicate_instance_exits_with_clear_error(
     err = capsys.readouterr().err
     assert "another Host Agent instance" in err
     assert str(lock_path) in err
+
+
+def test_mcp_token_subcommand_prints_token(tmp_path, capsys, monkeypatch) -> None:
+    monkeypatch.setenv("HOST_AGENT_IDENTITY_PATH", str(tmp_path / "host_identity.json"))
+    monkeypatch.setenv("HOST_AGENT_LOCAL_ACCOUNT_PATH", str(tmp_path / "host_local_account.json"))
+    # Also set control plane URL to satisfy config loading
+    monkeypatch.setenv("HOST_AGENT_CONTROL_PLANE_URL", "https://cloud.example")
+    from host_agent.cli import main
+
+    main(["mcp-token"])
+    out = capsys.readouterr().out.strip()
+    assert len(out) >= 40  # token is ~43 chars
+    # Subsequent invocation prints the same token (idempotent).
+    main(["mcp-token"])
+    out2 = capsys.readouterr().out.strip()
+    assert out == out2