diff --git a/swh/vault/cli.py b/swh/vault/cli.py
index 9129cf4..194225b 100644
--- a/swh/vault/cli.py
+++ b/swh/vault/cli.py
@@ -1,60 +1,73 @@
+import os
 import logging
 
 import click
 
+from swh.core.config import SWH_CONFIG_DIRECTORIES, SWH_CONFIG_EXTENSIONS
 from swh.core.cli import CONTEXT_SETTINGS, AliasedGroup
 
+from swh.vault.api.server import make_app_from_configfile, DEFAULT_CONFIG_PATH
+
+CFG_HELP = """Software Heritage Vault RPC server.
+
+If the CONFIGFILE option is not set, the default config file search will
+be used; first the SWH_CONFIG_FILENAME environment variable will be
+checked, then the config file will be searched in:
+
+%s""" % ('\n\n'.join('- %s(%s)' % (
+    os.path.join(d, DEFAULT_CONFIG_PATH), '|'.join(SWH_CONFIG_EXTENSIONS))
+                     for d in SWH_CONFIG_DIRECTORIES))
 
 @click.group(name='vault', context_settings=CONTEXT_SETTINGS,
              cls=AliasedGroup)
 @click.pass_context
 def vault(ctx):
     '''Software Heritage Vault tools.'''
     pass
 
 
-@vault.command(name='rpc-serve')
+@vault.command(name='rpc-serve', help=CFG_HELP)
 @click.option('--config-file', '-C', default=None,
+              metavar='CONFIGFILE',
               type=click.Path(exists=True, dir_okay=False,),
               help="Configuration file.")
 @click.option('--no-stdout', is_flag=True, default=False,
               help="Do NOT output logs on the console")
-@click.option('--host', default='0.0.0.0', help="Host to run the server")
+@click.option('--host', default='0.0.0.0',
+              metavar='IP', show_default=True,
+              help="Host ip address to bind the server on")
 @click.option('--port', default=5005, type=click.INT,
+              metavar='PORT',
               help="Binding port of the server")
 @click.option('--debug/--no-debug', default=True,
               help="Indicates if the server should run in debug mode")
 @click.pass_context
 def serve(ctx, config_file, no_stdout, host, port, debug):
-    """Software Heritage Vault API server
-
-    """
     import aiohttp
     from swh.scheduler.celery_backend.config import setup_log_handler
-    from swh.vault.api.server import make_app_from_configfile
 
     ctx.ensure_object(dict)
     setup_log_handler(
         loglevel=ctx.obj.get('log_level', logging.INFO), colorize=False,
         format='[%(levelname)s] %(name)s -- %(message)s',
         log_console=not no_stdout)
 
     try:
         app = make_app_from_configfile(config_file, debug=debug)
     except EnvironmentError as e:
         click.echo(e.msg, err=True)
         ctx.exit(1)
 
     aiohttp.web.run_app(app, host=host, port=int(port))
 
 
 vault.add_alias(serve, 'serve')
 
 
 def main():
     logging.basicConfig()
     return serve(auto_envvar_prefix='SWH_VAULT')
 
 
 if __name__ == '__main__':
     main()