Merge branch 'fix/cli-45-credential-envvar'

# Conflicts:
#	archreview/2026-07-12/remediation/00-tracking.md

clients/python/src/zb_mom_ww_mxgateway_cli/commands.py

@@ -32,6 +32,11 @@ logger = logging.getLogger(__name__)
 
 MAX_AGGREGATE_EVENTS = 10_000
 
+#: Canonical CLI credential environment variable, shared by every official client
+#: CLI (CLI-45) so one exported variable drives the same operator workflow in all
+#: five languages.
+DEFAULT_VERIFY_PASSWORD_ENV = "MXGATEWAY_VERIFY_PASSWORD"
+
 _BATCH_EOR = "__MXGW_BATCH_EOR__"
 
 
@@ -328,7 +333,8 @@ def write_secured(**kwargs: Any) -> None:
 )
 @click.option(
     "--password-env",
-    default=None,
+    default=DEFAULT_VERIFY_PASSWORD_ENV,
+    show_default=True,
     help="Environment variable holding the user password.",
 )
 @click.option("--correlation-id", default="", help="Client correlation id.")
@@ -834,17 +840,23 @@ async def _authenticate_user(**kwargs: Any) -> dict[str, Any]:
 def _resolve_password(kwargs: dict[str, Any]) -> str:
     """Resolve the authenticate-user password from --password or --password-env.
 
-    Prefers the explicit flag, then falls back to the named environment
-    variable. The resolved secret is never echoed; callers pass it into the
-    ``secrets`` redaction list so it cannot leak through a surfaced error.
+    Prefers the explicit flag, then falls back to the environment variable named
+    by ``--password-env`` (default :data:`DEFAULT_VERIFY_PASSWORD_ENV`). A missing
+    *or empty* value from either source is a usage error (CLI-45): the CLI never
+    sends a fabricated empty credential to the wire. The error names the option
+    and the variable only — the resolved secret is never echoed, and callers pass
+    it into the ``secrets`` redaction list so it cannot leak through a surfaced
+    error either.
     """
 
+    env_name = kwargs.get("password_env") or DEFAULT_VERIFY_PASSWORD_ENV
     password = kwargs.get("password")
     if not password:
-        env_name = kwargs.get("password_env")
-        password = os.environ.get(env_name) if env_name else None
+        password = os.environ.get(env_name)
     if not password:
-        raise click.UsageError("a password is required via --password or --password-env")
+        raise click.UsageError(
+            f"a password is required via --password or the {env_name} environment variable"
+        )
     return password