diff --git a/crates/hiroz-codegen/src/resolver.rs b/crates/hiroz-codegen/src/resolver.rs
index d657201db..d9f6720c5 100644
--- a/crates/hiroz-codegen/src/resolver.rs
+++ b/crates/hiroz-codegen/src/resolver.rs
@@ -517,6 +517,7 @@ impl Resolver {
         // Add goal type description
         let goal_desc = goal.type_description();
         deps.insert(goal_desc.type_name.clone(), goal_desc.clone());
+        self.collect_nested_deps(&goal_desc, &mut deps);
 
         // Calculate action service hash (uses /action/ path instead of /srv/)
         let service_hash = crate::hashing::calculate_service_type_hash(
@@ -622,6 +623,7 @@ impl Resolver {
         // Add result type description
         let result_desc = result.type_description();
         deps.insert(result_desc.type_name.clone(), result_desc.clone());
+        self.collect_nested_deps(&result_desc, &mut deps);
 
         // Calculate action service hash
         let service_hash = crate::hashing::calculate_service_type_hash(
@@ -681,7 +683,8 @@ impl Resolver {
 
         // Add feedback type description
         let feedback_desc = feedback.type_description();
-        deps.insert(feedback_desc.type_name.clone(), feedback_desc);
+        deps.insert(feedback_desc.type_name.clone(), feedback_desc.clone());
+        self.collect_nested_deps(&feedback_desc, &mut deps);
 
         // Build TypeDescriptionMsg and calculate hash
         use crate::hashing::{TypeDescriptionMsg, to_hash_version, to_ros2_json};
diff --git a/crates/hiroz-codegen/tests/action_nested_deps.rs b/crates/hiroz-codegen/tests/action_nested_deps.rs
new file mode 100644
index 000000000..8cba2019c
--- /dev/null
+++ b/crates/hiroz-codegen/tests/action_nested_deps.rs
@@ -0,0 +1,83 @@
+//! Action Goal/Result/Feedback type hashing must include nested message
+//! dependencies, the same way plain service hashing already does.
+//!
+//! `tf2_msgs/LookupTransform` exercises both affected paths with one real,
+//! already-packaged fixture -- no synthetic types needed:
+//! - Result (`geometry_msgs/TransformStamped transform`, `tf2_msgs/TF2Error
+//!   error`): `TransformStamped` nests `std_msgs/Header` and
+//!   `geometry_msgs/Transform`, and `Transform` itself nests
+//!   `Vector3`/`Quaternion` -- multi-level nesting `calculate_get_result_hash`
+//!   silently dropped from its dependency set.
+//! - Goal (`builtin_interfaces/Duration timeout`, among primitives):
+//!   `Duration` is a nested dependency `calculate_send_goal_hash` never
+//!   inserted manually (unlike `builtin_interfaces/Time`, which every
+//!   action hash function adds by hand for the goal_id UUID) -- it was only
+//!   ever reachable via `collect_nested_deps`.
+//!
+//! Both were fixed by wiring `collect_nested_deps` into `resolver.rs`
+//! (fj#158, GitHub#334).
+
+use std::path::PathBuf;
+
+fn assets_dir() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("assets/jazzy")
+}
+
+#[test]
+fn test_lookup_transform_hashes_include_nested_deps() {
+    use hiroz_codegen::{
+        discovery::{discover_actions, discover_messages},
+        resolver::Resolver,
+    };
+
+    let assets = assets_dir();
+    let packages = [
+        "builtin_interfaces",
+        "unique_identifier_msgs",
+        "action_msgs",
+        "service_msgs",
+        "std_msgs",
+        "geometry_msgs",
+        "tf2_msgs",
+    ];
+    let mut all_messages = Vec::new();
+    for pkg in &packages {
+        let pkg_path = assets.join(pkg);
+        let msgs = discover_messages(&pkg_path, pkg).unwrap_or_default();
+        all_messages.extend(msgs);
+    }
+
+    let mut resolver = Resolver::new(false);
+    resolver
+        .resolve_messages(all_messages)
+        .expect("resolve messages");
+
+    let pkg_path = assets.join("tf2_msgs");
+    let actions = discover_actions(&pkg_path, "tf2_msgs").expect("discover actions");
+    let resolved = resolver.resolve_actions(actions).expect("resolve actions");
+    let lookup_transform = resolved
+        .iter()
+        .find(|a| a.parsed.name == "LookupTransform")
+        .expect("LookupTransform action");
+
+    // Pinned after fixing calculate_get_result_hash to call
+    // collect_nested_deps on the Result type, matching the plain-service
+    // path (resolver.rs:181-182). Before that fix this hash is computed
+    // over an incomplete dependency set (missing TransformStamped's own
+    // nested Header/Transform/Vector3/Quaternion types) and differs from
+    // this value -- this test must fail on unfixed code.
+    assert_eq!(
+        lookup_transform.get_result_hash.to_rihs_string(),
+        "RIHS01_3cd1715751899e3167b5aec3e4ac194f7da9e8493a77285f9f6a4c914f5e8b24",
+        "get_result hash mismatch -- nested dependency collection regressed"
+    );
+
+    // Same defect, the Goal side: calculate_send_goal_hash never inserted
+    // builtin_interfaces/Duration -- the Goal's `timeout` field -- so it
+    // was only ever reachable via collect_nested_deps too.
+    assert_eq!(
+        lookup_transform.send_goal_hash.to_rihs_string(),
+        "RIHS01_4646ff5706c86b04d0a1098d329951a9731a7517e16702905de6073cc72c8530",
+        "send_goal hash mismatch -- nested dependency collection regressed"
+    );
+}