diff --git a/pasch/__init__.py b/pasch/__init__.py
index e69de29..e6f54ec 100644
--- a/pasch/__init__.py
+++ b/pasch/__init__.py
@@ -0,0 +1,11 @@
+from . import modules
+from .cmd import run_capture, run_check
+from .orchestrator import Module, Orchestrator
+
+__all__: list[str] = [
+    "Module",
+    "Orchestrator",
+    "modules",
+    "run_capture",
+    "run_check",
+]
diff --git a/pasch/modules/__init__.py b/pasch/modules/__init__.py
new file mode 100644
index 0000000..6103a92
--- /dev/null
+++ b/pasch/modules/__init__.py
@@ -0,0 +1,5 @@
+from .echo import Echo
+
+__all__: list[str] = [
+    "Echo",
+]
diff --git a/pasch/modules/echo.py b/pasch/modules/echo.py
new file mode 100644
index 0000000..11a3202
--- /dev/null
+++ b/pasch/modules/echo.py
@@ -0,0 +1,14 @@
+from pasch.cmd import run_check
+from pasch.orchestrator import Module, Orchestrator
+
+
+class Echo(Module):
+    def __init__(self, orchestrator: Orchestrator) -> None:
+        super().__init__(orchestrator)
+        self.args: list[str] = []
+
+    def add(self, arg: str) -> None:
+        self.args.append(arg)
+
+    def realize(self) -> None:
+        run_check("echo", *self.args)
diff --git a/pasch/orchestrator.py b/pasch/orchestrator.py
new file mode 100644
index 0000000..d205629
--- /dev/null
+++ b/pasch/orchestrator.py
@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+
+
+class Module(ABC):
+    def __init__(self, orchestrator: Orchestrator) -> None:
+        self.orchestrator = orchestrator
+        self.orchestrator.register(self)
+
+    @abstractmethod
+    def realize(self) -> None: ...
+
+
+class Orchestrator:
+    def __init__(self) -> None:
+        self.frozen: bool = False
+        self.modules: list[Module] = []
+
+    def register(self, module: Module) -> None:
+        if self.frozen:
+            raise Exception("registering module wile orchestrator is frozen")
+        self.modules.append(module)
+
+    def realize(self) -> None:
+        self.frozen = True
+        for module in reversed(self.modules):
+            module.realize()
diff --git a/scripts/check b/scripts/check
new file mode 100755
index 0000000..40ef2a2
--- /dev/null
+++ b/scripts/check
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+uvx ruff check
+uvx pyrefly check