diff --git a/niar/__init__.py b/niar/__init__.py
index aa239e1..36415c7 100644
--- a/niar/__init__.py
+++ b/niar/__init__.py
@@ -12,15 +12,13 @@ def cli(np: Project):
     subparsers = parser.add_subparsers(required=True)
 
     build.add_arguments(
-        np,
-        subparsers.add_parser(
-            "build", help="build the design, and optionally program it"
-        ),
-    )
+        np, subparsers.add_parser("build", help="build the design, and optionally program it"))
     if np.cxxrtl_targets:
         cxxrtl.add_arguments(
-            np, subparsers.add_parser("cxxrtl", help="run the C++ simulator tests")
-        )
+            np, subparsers.add_parser("cxxrtl", help="run the C++ simulator tests"))
+
+    for command in np.commands:
+        command.add_arguments(np, subparsers.add_parser(command.name, help=command.help))
 
     args = parser.parse_args()
     args.func(args)
diff --git a/niar/command.py b/niar/command.py
new file mode 100644
index 0000000..8acc1da
--- /dev/null
+++ b/niar/command.py
@@ -0,0 +1,13 @@
+from typing import Callable
+
+__all__ = ["Command"]
+
+class Command:
+    add_arguments: Callable
+    name: str
+    help: str
+
+    def __init__(self, *, add_arguments, help):
+        self.add_arguments = add_arguments
+        self.name = add_arguments.__name__
+        self.help = help
diff --git a/niar/project.py b/niar/project.py
index ff84eea..9ef1e28 100644
--- a/niar/project.py
+++ b/niar/project.py
@@ -6,6 +6,7 @@ from typing import Optional
 from amaranth import Elaboratable
 from amaranth.build import Platform
 
+from .command import Command
 from .cxxrtl_platform import CxxrtlPlatform
 
 __all__ = ["Project"]
@@ -84,6 +85,7 @@ class Project:
     targets: list[type[Platform]]
     cxxrtl_targets: list[type[CxxrtlPlatform]] = []
     externals: list[str] = []
+    commands: list[Command] = []
 
     origin: Path
 
@@ -118,6 +120,12 @@ class Project:
             required=False,
             isinstance_list=str,
         ),
+        Prop(
+            "commands",
+            description="a list of Command objects which extend the CLI",
+            required=False,
+            isinstance_list=Command,
+        ),
     ]
 
     def __init_subclass__(cls):
@@ -164,6 +172,15 @@ class Project:
     def path(self):
         return ProjectPath(self)
 
+    @classmethod
+    def command(cls, *, help):
+        def inner(add_arguments):
+            cls.commands.append(Command(
+                add_arguments=add_arguments,
+                help=help,
+            ))
+        return inner
+
 
 class ProjectPath:
     def __init__(self, np: Project):