diff --git a/src/lib/options.test.ts b/src/lib/options.test.ts
new file mode 100644
index 0000000..77c08cd
--- /dev/null
+++ b/src/lib/options.test.ts
@@ -0,0 +1,28 @@
+import { parse } from "../parser";
+import { Script, TextPiece } from "../words";
+import { getOpt, Options } from "./options";
+
+describe("getOpt", () => {
+  const expectOpts = <P extends Options>(command: string, opts: P) => {
+    const [ok, script] = parse(command);
+    expect(ok).toBeTruthy();
+    return expect(getOpt((script as Script)[0] as TextPiece[], opts));
+  };
+
+  it("parses empty arguments", () => expectOpts("cmd", {}).toEqual([{}]));
+  it("parses single positional arguments", () =>
+    expectOpts("cmd apple", {}).toEqual([{}, "apple"]));
+  it("parses multiple positional arguments", () =>
+    expectOpts("cmd apple banana", {}).toEqual([{}, "apple", "banana"]));
+
+  it("enforces minimum # of arguments", () =>
+    expectOpts("cmd", { $min: 1 }).toEqual([
+      { error: "cmd: Not enough arguments" },
+    ]));
+  it("enforces maximum # of arguments", () =>
+    expectOpts("cmd apple banana", { $max: 1 }).toEqual([
+      { error: "cmd: Too many arguments" },
+    ]));
+  it("allows # of arguments in-spec", () =>
+    expectOpts("cmd apple", { $min: 1, $max: 1 }).toEqual([{}, "apple"]));
+});
diff --git a/src/lib/options.ts b/src/lib/options.ts
index 3568f9d..7843fc3 100644
--- a/src/lib/options.ts
+++ b/src/lib/options.ts
@@ -1,11 +1,11 @@
-import { AsText, TextPiece } from '../words';
+import { AsText, TextPiece } from "../words";
 
-type SwitchPattern = Record<string, number> & {
-  min?: number;
-  max?: number;
+export type Options = Record<string, number> & {
+  $min?: number;
+  $max?: number;
 };
-type SwitchOutput<P extends SwitchPattern> = {
-  [K in keyof P]: K extends "min" | "max"
+type ParsedOptions<P extends Options> = {
+  [K in keyof P]: K extends "$min" | "$max"
     ? never
     : P[K] extends 0
     ? boolean
@@ -14,20 +14,39 @@ type SwitchOutput<P extends SwitchPattern> = {
   error?: string;
 };
 
-// TODO: tests and error handling
-export function getOpt<P extends SwitchPattern>(
+export function getOpt<P extends Options>(
   argv: TextPiece[],
-  switches: P
-): [SwitchOutput<P>, ...string[]] {
-  const [flags, textPieces] = getOptRaw(argv, switches);
+  options: P
+): [ParsedOptions<P>, ...string[]] {
+  const [flags, textPieces] = getOptRaw(argv, options);
   return [flags, ...textPieces.map(AsText)];
 }
 
-export function getOptRaw<P extends SwitchPattern>(
+export function getOptRaw<P extends Options>(
   argv: TextPiece[],
-  switches: P
-): [SwitchOutput<P>, TextPiece[]] {
-  const [, ...words] = argv;
-  // TODO: handle min/max
-  return [{} as SwitchOutput<P>, words];
+  options: P
+): [ParsedOptions<P>, TextPiece[]] {
+  const [cmd, ...words] = argv;
+  const result: ParsedOptions<P> = Object.fromEntries(
+    Object.entries(options)
+      .filter(([name]) => name != "$min" && name != "$max")
+      .map(([name]) => [])
+  );
+
+  // TODO: parse switches
+
+  if (options.$min !== undefined && options.$min > words.length) {
+    return [
+      { error: `${AsText(cmd)}: Not enough arguments` } as ParsedOptions<P>,
+      [],
+    ];
+  }
+  if (options.$max !== undefined && options.$max < words.length) {
+    return [
+      { error: `${AsText(cmd)}: Too many arguments` } as ParsedOptions<P>,
+      [],
+    ];
+  }
+
+  return [result, words];
 }