diff --git a/crates/aiken-lang/src/ast.rs b/crates/aiken-lang/src/ast.rs
index c5ffd510..23cf2925 100644
--- a/crates/aiken-lang/src/ast.rs
+++ b/crates/aiken-lang/src/ast.rs
@@ -691,6 +691,7 @@ pub struct ArgVia<T, Expr> {
     pub location: Span,
     pub via: Expr,
     pub tipo: T,
+    pub annotation: Option<Annotation>,
 }
 
 impl<T, Ann> From<ArgVia<T, Ann>> for Arg<T> {
diff --git a/crates/aiken-lang/src/parser/definition/snapshots/def_invalid_property_test.snap b/crates/aiken-lang/src/parser/definition/snapshots/def_invalid_property_test.snap
index 66cabfe5..e7c37498 100644
--- a/crates/aiken-lang/src/parser/definition/snapshots/def_invalid_property_test.snap
+++ b/crates/aiken-lang/src/parser/definition/snapshots/def_invalid_property_test.snap
@@ -12,12 +12,13 @@ Test(
                     location: 9..10,
                     is_validator_param: false,
                 },
-                location: 9..16,
+                location: 9..10,
                 via: Var {
                     location: 15..16,
                     name: "f",
                 },
                 tipo: (),
+                annotation: None,
             },
             ArgVia {
                 arg_name: Named {
@@ -26,12 +27,13 @@ Test(
                     location: 18..19,
                     is_validator_param: false,
                 },
-                location: 18..25,
+                location: 18..19,
                 via: Var {
                     location: 24..25,
                     name: "g",
                 },
                 tipo: (),
+                annotation: None,
             },
         ],
         body: Var {
diff --git a/crates/aiken-lang/src/parser/definition/snapshots/def_property_test.snap b/crates/aiken-lang/src/parser/definition/snapshots/def_property_test.snap
index b159b1f5..db3b686e 100644
--- a/crates/aiken-lang/src/parser/definition/snapshots/def_property_test.snap
+++ b/crates/aiken-lang/src/parser/definition/snapshots/def_property_test.snap
@@ -12,7 +12,7 @@ Test(
                     location: 9..10,
                     is_validator_param: false,
                 },
-                location: 9..27,
+                location: 9..10,
                 via: FieldAccess {
                     location: 15..27,
                     label: "any_int",
@@ -22,6 +22,7 @@ Test(
                     },
                 },
                 tipo: (),
+                annotation: None,
             },
         ],
         body: Var {
diff --git a/crates/aiken-lang/src/parser/definition/snapshots/def_property_test_annotated_fuzzer.snap b/crates/aiken-lang/src/parser/definition/snapshots/def_property_test_annotated_fuzzer.snap
new file mode 100644
index 00000000..295bde81
--- /dev/null
+++ b/crates/aiken-lang/src/parser/definition/snapshots/def_property_test_annotated_fuzzer.snap
@@ -0,0 +1,55 @@
+---
+source: crates/aiken-lang/src/parser/definition/test.rs
+description: "Code:\n\ntest foo(x: Int via foo()) {\n    True\n}\n"
+---
+Test(
+    Function {
+        arguments: [
+            ArgVia {
+                arg_name: Named {
+                    name: "x",
+                    label: "x",
+                    location: 9..10,
+                    is_validator_param: false,
+                },
+                location: 9..15,
+                via: Call {
+                    arguments: [],
+                    fun: Var {
+                        location: 20..23,
+                        name: "foo",
+                    },
+                    location: 20..25,
+                },
+                tipo: (),
+                annotation: Some(
+                    Constructor {
+                        location: 12..15,
+                        module: None,
+                        name: "Int",
+                        arguments: [],
+                    },
+                ),
+            },
+        ],
+        body: Var {
+            location: 33..37,
+            name: "True",
+        },
+        doc: None,
+        location: 0..26,
+        name: "foo",
+        public: false,
+        return_annotation: Some(
+            Constructor {
+                location: 0..39,
+                module: None,
+                name: "Bool",
+                arguments: [],
+            },
+        ),
+        return_type: (),
+        end_position: 38,
+        can_error: false,
+    },
+)
diff --git a/crates/aiken-lang/src/parser/definition/test.rs b/crates/aiken-lang/src/parser/definition/test.rs
index 748c187e..cbd57a23 100644
--- a/crates/aiken-lang/src/parser/definition/test.rs
+++ b/crates/aiken-lang/src/parser/definition/test.rs
@@ -4,6 +4,7 @@ use crate::{
     ast,
     expr::UntypedExpr,
     parser::{
+        annotation,
         chain::{call::parser as call, field_access, tuple_index::parser as tuple_index, Chain},
         error::ParseError,
         expr::{self, var},
@@ -67,11 +68,13 @@ pub fn via() -> impl Parser<Token, ast::UntypedArgVia, Error = ParseError> {
             }
         }),
     ))
+    .then(just(Token::Colon).ignore_then(annotation()).or_not())
     .then_ignore(just(Token::Via))
     .then(fuzzer())
-    .map_with_span(|(arg_name, via), location| ast::ArgVia {
+    .map_with_span(|((arg_name, annotation), via), location| ast::ArgVia {
         arg_name,
         via,
+        annotation,
         tipo: (),
         location,
     })
@@ -144,4 +147,15 @@ mod tests {
             "#
         );
     }
+
+    #[test]
+    fn def_property_test_annotated_fuzzer() {
+        assert_definition!(
+            r#"
+            test foo(x: Int via foo()) {
+                True
+            }
+            "#
+        );
+    }
 }
diff --git a/crates/aiken-lang/src/tipo/infer.rs b/crates/aiken-lang/src/tipo/infer.rs
index 10027676..5c02eb94 100644
--- a/crates/aiken-lang/src/tipo/infer.rs
+++ b/crates/aiken-lang/src/tipo/infer.rs
@@ -344,9 +344,16 @@ fn infer_definition(
                     let typed_via =
                         ExprTyper::new(environment, lines, tracing).infer(arg.via.clone())?;
 
-                    let (annotation, inner_type) = infer_fuzzer(&typed_via.tipo(), &arg.location)?;
+                    let (inferred_annotation, inner_type) =
+                        infer_fuzzer(&typed_via.tipo(), &arg.location)?;
 
-                    Ok((Some((typed_via, inner_type)), Some(annotation)))
+                    if let Some(ref provided_annotation) = arg.annotation {
+                        if !provided_annotation.is_logically_equal(&inferred_annotation) {
+                            todo!("Inferred annotation doesn't match actual annotation.")
+                        }
+                    }
+
+                    Ok((Some((typed_via, inner_type)), Some(inferred_annotation)))
                 }
                 None => Ok((None, None)),
             }?;
@@ -401,6 +408,7 @@ fn infer_definition(
                             .to_owned();
 
                         vec![ArgVia {
+                            annotation,
                             arg_name,
                             location,
                             tipo,