diff --git a/tests/golden_tests.rs b/tests/golden_tests.rs
index a1abda466..f45e066e0 100644
--- a/tests/golden_tests.rs
+++ b/tests/golden_tests.rs
@@ -15,6 +15,7 @@ use std::{
   collections::HashMap,
   fmt::Write,
   fs,
+  io::Read,
   path::{Path, PathBuf},
   str::FromStr,
   sync::{Arc, RwLock},
@@ -72,7 +73,7 @@ fn run_golden_test_dir_multiple(test_name: &str, run: &[&dyn Fn(&str, &Path) ->
 
   let walker = WalkDir::new(&root).sort_by_file_name().max_depth(2).into_iter().filter_entry(|e| {
     let path = e.path();
-    path == root || (path.is_file() && path.extension().is_some_and(|x| x == "hvm"))
+    path == root || path.is_dir() || (path.is_file() && path.extension().is_some_and(|x| x == "hvm"))
   });
 
   for entry in walker {
@@ -305,3 +306,21 @@ fn run_entrypoint() {
     Ok(format!("{}{}", display_readback_errors(&info.readback_errors), res))
   })
 }
+
+#[test]
+fn cli() {
+  run_golden_test_dir(function_name!(), &|_code, path| {
+    let mut args_path = PathBuf::from(path);
+    assert!(args_path.set_extension("args"));
+
+    let mut args_buf = String::with_capacity(16);
+    let mut args_file = fs::File::open(args_path).expect("File exists");
+    args_file.read_to_string(&mut args_buf).expect("Read args");
+    let args = args_buf.lines();
+
+    let output =
+      std::process::Command::new("cargo").arg("run").arg("-q").args(args).output().expect("Run process");
+
+    Ok(format!("{}\n{}", String::from_utf8_lossy(&output.stderr), String::from_utf8_lossy(&output.stdout)))
+  })
+}
diff --git a/tests/golden_tests/cli/compile_all.args b/tests/golden_tests/cli/compile_all.args
new file mode 100644
index 000000000..8d1a454ff
--- /dev/null
+++ b/tests/golden_tests/cli/compile_all.args
@@ -0,0 +1,3 @@
+compile
+tests/golden_tests/cli/compile_all.hvm
+-Oall
diff --git a/tests/golden_tests/cli/compile_all.hvm b/tests/golden_tests/cli/compile_all.hvm
new file mode 100644
index 000000000..39799e5be
--- /dev/null
+++ b/tests/golden_tests/cli/compile_all.hvm
@@ -0,0 +1,6 @@
+data Pair
+  = (Pair fst snd)
+
+Pair.get f (Pair fst snd) = (f fst snd)
+
+main = (Pair.get @x @y (+ x y) (Pair 40 2))
diff --git a/tests/golden_tests/cli/compile_no_opts.args b/tests/golden_tests/cli/compile_no_opts.args
new file mode 100644
index 000000000..997cd69b0
--- /dev/null
+++ b/tests/golden_tests/cli/compile_no_opts.args
@@ -0,0 +1,11 @@
+compile
+tests/golden_tests/cli/compile_no_opts.hvm
+-Ono-all
+-Ono-eta
+-Ono-prune
+-Ono-ref-to-ref
+-Ono-pre-reduce
+-Ono-float-combinators
+-Ono-simplify-main
+-Ono-merge
+-Ono-inline
diff --git a/tests/golden_tests/cli/compile_no_opts.hvm b/tests/golden_tests/cli/compile_no_opts.hvm
new file mode 100644
index 000000000..c6ec074e6
--- /dev/null
+++ b/tests/golden_tests/cli/compile_no_opts.hvm
@@ -0,0 +1 @@
+main = *
diff --git a/tests/golden_tests/cli/compile_pre_reduce.args b/tests/golden_tests/cli/compile_pre_reduce.args
new file mode 100644
index 000000000..8347d2f98
--- /dev/null
+++ b/tests/golden_tests/cli/compile_pre_reduce.args
@@ -0,0 +1,3 @@
+compile
+tests/golden_tests/cli/compile_pre_reduce.hvm
+-Opre-reduce
diff --git a/tests/golden_tests/cli/compile_pre_reduce.hvm b/tests/golden_tests/cli/compile_pre_reduce.hvm
new file mode 100644
index 000000000..1bb88cb5e
--- /dev/null
+++ b/tests/golden_tests/cli/compile_pre_reduce.hvm
@@ -0,0 +1,3 @@
+I = (+ 2 3)
+
+main = *
diff --git a/tests/golden_tests/cli/compile_wrong_opt.args b/tests/golden_tests/cli/compile_wrong_opt.args
new file mode 100644
index 000000000..f00d73fee
--- /dev/null
+++ b/tests/golden_tests/cli/compile_wrong_opt.args
@@ -0,0 +1,3 @@
+compile
+tests/golden_tests/cli/compile_wrong_opt.hvm
+-Ofoo
diff --git a/tests/golden_tests/cli/compile_wrong_opt.hvm b/tests/golden_tests/cli/compile_wrong_opt.hvm
new file mode 100644
index 000000000..c6ec074e6
--- /dev/null
+++ b/tests/golden_tests/cli/compile_wrong_opt.hvm
@@ -0,0 +1 @@
+main = *
diff --git a/tests/golden_tests/cli/desugar_bool_scott.args b/tests/golden_tests/cli/desugar_bool_scott.args
new file mode 100644
index 000000000..feba903b6
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_bool_scott.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_bool_scott.hvm
+-Oadt-scott
diff --git a/tests/golden_tests/cli/desugar_bool_scott.hvm b/tests/golden_tests/cli/desugar_bool_scott.hvm
new file mode 100644
index 000000000..5278329e0
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_bool_scott.hvm
@@ -0,0 +1,3 @@
+data Boolean = True | False
+
+main = True
diff --git a/tests/golden_tests/cli/desugar_bool_tagged.args b/tests/golden_tests/cli/desugar_bool_tagged.args
new file mode 100644
index 000000000..a4d9ed077
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_bool_tagged.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_bool_tagged.hvm
+-Oadt-tagged-scott
diff --git a/tests/golden_tests/cli/desugar_bool_tagged.hvm b/tests/golden_tests/cli/desugar_bool_tagged.hvm
new file mode 100644
index 000000000..5278329e0
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_bool_tagged.hvm
@@ -0,0 +1,3 @@
+data Boolean = True | False
+
+main = True
diff --git a/tests/golden_tests/cli/desugar_eta.args b/tests/golden_tests/cli/desugar_eta.args
new file mode 100644
index 000000000..b7547139e
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_eta.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_eta.hvm
+-Oeta
diff --git a/tests/golden_tests/cli/desugar_eta.hvm b/tests/golden_tests/cli/desugar_eta.hvm
new file mode 100644
index 000000000..93e6d7a1b
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_eta.hvm
@@ -0,0 +1,4 @@
+id x = x
+id2 x = (id x)
+
+main = (id2 42)
diff --git a/tests/golden_tests/cli/desugar_float_combinators.args b/tests/golden_tests/cli/desugar_float_combinators.args
new file mode 100644
index 000000000..b432da5ab
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_float_combinators.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_float_combinators.hvm
+-Ofloat-combinators
diff --git a/tests/golden_tests/cli/desugar_float_combinators.hvm b/tests/golden_tests/cli/desugar_float_combinators.hvm
new file mode 100644
index 000000000..5af1723a7
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_float_combinators.hvm
@@ -0,0 +1,6 @@
+Z =    @s @z z
+S = @x @s @z (s (x s z))
+
+get = @Nat (Nat @x (+ x 1) 0)
+
+main = (get (S (S Z)))
diff --git a/tests/golden_tests/cli/desugar_inline.args b/tests/golden_tests/cli/desugar_inline.args
new file mode 100644
index 000000000..983091dda
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_inline.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_inline.hvm
+-Oinline
diff --git a/tests/golden_tests/cli/desugar_inline.hvm b/tests/golden_tests/cli/desugar_inline.hvm
new file mode 100644
index 000000000..6ce0570da
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_inline.hvm
@@ -0,0 +1,3 @@
+id x = x
+
+main = (id id)
diff --git a/tests/golden_tests/cli/desugar_linearize_matches.args b/tests/golden_tests/cli/desugar_linearize_matches.args
new file mode 100644
index 000000000..144ea324a
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_linearize_matches.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_linearize_matches.hvm
+-Olinearize-matches
diff --git a/tests/golden_tests/cli/desugar_linearize_matches.hvm b/tests/golden_tests/cli/desugar_linearize_matches.hvm
new file mode 100644
index 000000000..3980330ab
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_linearize_matches.hvm
@@ -0,0 +1 @@
+main = λa λb match a { 0: b; 1+: b }
diff --git a/tests/golden_tests/cli/desugar_linearize_matches_extra.args b/tests/golden_tests/cli/desugar_linearize_matches_extra.args
new file mode 100644
index 000000000..2d6822111
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_linearize_matches_extra.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_linearize_matches_extra.hvm
+-Olinearize-matches-extra
diff --git a/tests/golden_tests/cli/desugar_linearize_matches_extra.hvm b/tests/golden_tests/cli/desugar_linearize_matches_extra.hvm
new file mode 100644
index 000000000..64a20adb8
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_linearize_matches_extra.hvm
@@ -0,0 +1 @@
+main = λa λb λc match a { 0: b; 1+: c }
diff --git a/tests/golden_tests/cli/desugar_merge.args b/tests/golden_tests/cli/desugar_merge.args
new file mode 100644
index 000000000..698a9b365
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_merge.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_merge.hvm
+-Omerge
diff --git a/tests/golden_tests/cli/desugar_merge.hvm b/tests/golden_tests/cli/desugar_merge.hvm
new file mode 100644
index 000000000..fb7c11a81
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_merge.hvm
@@ -0,0 +1,4 @@
+F = @t @f f
+Z = @s @z z
+
+main = (F)
diff --git a/tests/golden_tests/cli/desugar_prune.args b/tests/golden_tests/cli/desugar_prune.args
new file mode 100644
index 000000000..4b1dc1b4e
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_prune.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_prune.hvm
+-Oprune
diff --git a/tests/golden_tests/cli/desugar_prune.hvm b/tests/golden_tests/cli/desugar_prune.hvm
new file mode 100644
index 000000000..e1368b9e3
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_prune.hvm
@@ -0,0 +1,3 @@
+id x = x
+
+main = *
diff --git a/tests/golden_tests/cli/desugar_ref_to_ref.args b/tests/golden_tests/cli/desugar_ref_to_ref.args
new file mode 100644
index 000000000..41568b563
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_ref_to_ref.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_ref_to_ref.hvm
+-Oref-to-ref
diff --git a/tests/golden_tests/cli/desugar_ref_to_ref.hvm b/tests/golden_tests/cli/desugar_ref_to_ref.hvm
new file mode 100644
index 000000000..17dc21c52
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_ref_to_ref.hvm
@@ -0,0 +1,5 @@
+Foo = λ* 0
+
+Bar = Foo
+
+Main = (Bar *)
diff --git a/tests/golden_tests/cli/desugar_simplify_main.args b/tests/golden_tests/cli/desugar_simplify_main.args
new file mode 100644
index 000000000..27b9743c7
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_simplify_main.args
@@ -0,0 +1,3 @@
+desugar
+tests/golden_tests/cli/desugar_simplify_main.hvm
+-Osimplify-main
diff --git a/tests/golden_tests/cli/desugar_simplify_main.hvm b/tests/golden_tests/cli/desugar_simplify_main.hvm
new file mode 100644
index 000000000..9d8ed665e
--- /dev/null
+++ b/tests/golden_tests/cli/desugar_simplify_main.hvm
@@ -0,0 +1,3 @@
+id = λx x
+
+main = id
diff --git a/tests/golden_tests/cli/run_add.args b/tests/golden_tests/cli/run_add.args
new file mode 100644
index 000000000..7dcce0dd1
--- /dev/null
+++ b/tests/golden_tests/cli/run_add.args
@@ -0,0 +1,4 @@
+run
+tests/golden_tests/cli/run_add.hvm
+3
+6
diff --git a/tests/golden_tests/cli/run_add.hvm b/tests/golden_tests/cli/run_add.hvm
new file mode 100644
index 000000000..60f845976
--- /dev/null
+++ b/tests/golden_tests/cli/run_add.hvm
@@ -0,0 +1 @@
+main a b = (+ a b)
diff --git a/tests/snapshots/cli__compile_all.hvm.snap b/tests/snapshots/cli__compile_all.hvm.snap
new file mode 100644
index 000000000..e5dbf3122
--- /dev/null
+++ b/tests/snapshots/cli__compile_all.hvm.snap
@@ -0,0 +1,10 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/compile_all.hvm
+---
+@Pair = (a (b {2 {2 a {2 b c}} c}))
+@Pair.get = (a ({2 @Pair.get$S0 (a b)} b))
+@Pair.get$S0 = {2 a {2 b ((a (b c)) c)}}
+@main = a
+& @Pair.get ~ ((<+ b c> (b c)) (d a))
+& @Pair ~ (#40 (#2 d))
diff --git a/tests/snapshots/cli__compile_no_opts.hvm.snap b/tests/snapshots/cli__compile_no_opts.hvm.snap
new file mode 100644
index 000000000..e04fe3b66
--- /dev/null
+++ b/tests/snapshots/cli__compile_no_opts.hvm.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/compile_no_opts.hvm
+---
+@main = *
diff --git a/tests/snapshots/cli__compile_pre_reduce.hvm.snap b/tests/snapshots/cli__compile_pre_reduce.hvm.snap
new file mode 100644
index 000000000..e02d96d53
--- /dev/null
+++ b/tests/snapshots/cli__compile_pre_reduce.hvm.snap
@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/compile_pre_reduce.hvm
+---
+Warnings:
+Unused definition 'I'.
+
+@I = #5
+@main = *
diff --git a/tests/snapshots/cli__compile_wrong_opt.hvm.snap b/tests/snapshots/cli__compile_wrong_opt.hvm.snap
new file mode 100644
index 000000000..a515e011c
--- /dev/null
+++ b/tests/snapshots/cli__compile_wrong_opt.hvm.snap
@@ -0,0 +1,10 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/compile_wrong_opt.hvm
+---
+error: invalid value 'foo' for '-O <COMP_OPTS>'
+  [possible values: all, no-all, eta, no-eta, prune, no-prune, ref-to-ref, no-ref-to-ref, pre-reduce, no-pre-reduce, linearize-matches, linearize-matches-extra, no-linearize-matches, float-combinators, no-float-combinators, simplify-main, no-simplify-main, merge, no-merge, inline, no-inline, adt-scott, adt-tagged-scott]
+
+  tip: a similar value exists: 'float-combinators'
+
+For more information, try '--help'.
diff --git a/tests/snapshots/cli__desugar_bool_scott.hvm.snap b/tests/snapshots/cli__desugar_bool_scott.hvm.snap
new file mode 100644
index 000000000..b66ce163b
--- /dev/null
+++ b/tests/snapshots/cli__desugar_bool_scott.hvm.snap
@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_bool_scott.hvm
+---
+(main) = True
+
+(False) = λ* λb b
+
+(True) = λa λ* a
diff --git a/tests/snapshots/cli__desugar_bool_tagged.hvm.snap b/tests/snapshots/cli__desugar_bool_tagged.hvm.snap
new file mode 100644
index 000000000..ca24321d9
--- /dev/null
+++ b/tests/snapshots/cli__desugar_bool_tagged.hvm.snap
@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_bool_tagged.hvm
+---
+(main) = True
+
+(False) = #Boolean λ* #Boolean λb b
+
+(True) = #Boolean λa #Boolean λ* a
diff --git a/tests/snapshots/cli__desugar_eta.hvm.snap b/tests/snapshots/cli__desugar_eta.hvm.snap
new file mode 100644
index 000000000..f45582f9b
--- /dev/null
+++ b/tests/snapshots/cli__desugar_eta.hvm.snap
@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_eta.hvm
+---
+(id) = λa a
+
+(id2) = id
+
+(main) = (id2 42)
diff --git a/tests/snapshots/cli__desugar_float_combinators.hvm.snap b/tests/snapshots/cli__desugar_float_combinators.hvm.snap
new file mode 100644
index 000000000..bf760b87d
--- /dev/null
+++ b/tests/snapshots/cli__desugar_float_combinators.hvm.snap
@@ -0,0 +1,13 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_float_combinators.hvm
+---
+(Z) = λ* λb b
+
+(S) = λa λb let {b b_2} = b; λc (b (a b_2 c))
+
+(get) = λa (a get$S0 0)
+
+(main) = (get (S (S Z)))
+
+(get$S0) = λb (+ b 1)
diff --git a/tests/snapshots/cli__desugar_inline.hvm.snap b/tests/snapshots/cli__desugar_inline.hvm.snap
new file mode 100644
index 000000000..e7dc94c19
--- /dev/null
+++ b/tests/snapshots/cli__desugar_inline.hvm.snap
@@ -0,0 +1,7 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_inline.hvm
+---
+(id) = λa a
+
+(main) = (λa a λa a)
diff --git a/tests/snapshots/cli__desugar_linearize_matches.hvm.snap b/tests/snapshots/cli__desugar_linearize_matches.hvm.snap
new file mode 100644
index 000000000..571a93b11
--- /dev/null
+++ b/tests/snapshots/cli__desugar_linearize_matches.hvm.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_linearize_matches.hvm
+---
+(main) = λa λb (match a { 0: λc c; 1+: λ* λf f } b)
diff --git a/tests/snapshots/cli__desugar_linearize_matches_extra.hvm.snap b/tests/snapshots/cli__desugar_linearize_matches_extra.hvm.snap
new file mode 100644
index 000000000..47e449878
--- /dev/null
+++ b/tests/snapshots/cli__desugar_linearize_matches_extra.hvm.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_linearize_matches_extra.hvm
+---
+(main) = λa λb λc (match a { 0: λd λ* d; 1+: λ* λ* λi i } b c)
diff --git a/tests/snapshots/cli__desugar_merge.hvm.snap b/tests/snapshots/cli__desugar_merge.hvm.snap
new file mode 100644
index 000000000..1a2ab0a4e
--- /dev/null
+++ b/tests/snapshots/cli__desugar_merge.hvm.snap
@@ -0,0 +1,7 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_merge.hvm
+---
+(F_$_Z) = λ* λb b
+
+(main) = F_$_Z
diff --git a/tests/snapshots/cli__desugar_prune.hvm.snap b/tests/snapshots/cli__desugar_prune.hvm.snap
new file mode 100644
index 000000000..bc2572e63
--- /dev/null
+++ b/tests/snapshots/cli__desugar_prune.hvm.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_prune.hvm
+---
+(main) = *
diff --git a/tests/snapshots/cli__desugar_ref_to_ref.hvm.snap b/tests/snapshots/cli__desugar_ref_to_ref.hvm.snap
new file mode 100644
index 000000000..01462e5f6
--- /dev/null
+++ b/tests/snapshots/cli__desugar_ref_to_ref.hvm.snap
@@ -0,0 +1,9 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_ref_to_ref.hvm
+---
+(Foo) = λ* 0
+
+(Bar) = Foo
+
+(Main) = (Foo *)
diff --git a/tests/snapshots/cli__desugar_simplify_main.hvm.snap b/tests/snapshots/cli__desugar_simplify_main.hvm.snap
new file mode 100644
index 000000000..33d622376
--- /dev/null
+++ b/tests/snapshots/cli__desugar_simplify_main.hvm.snap
@@ -0,0 +1,7 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/desugar_simplify_main.hvm
+---
+(id) = λa a
+
+(main) = λa a
diff --git a/tests/snapshots/cli__run_add.hvm.snap b/tests/snapshots/cli__run_add.hvm.snap
new file mode 100644
index 000000000..20a061607
--- /dev/null
+++ b/tests/snapshots/cli__run_add.hvm.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/cli/run_add.hvm
+---
+9