diff --git a/techtree-manager/src/main.rs b/techtree-manager/src/main.rs
index cba851d..eda6053 100644
--- a/techtree-manager/src/main.rs
+++ b/techtree-manager/src/main.rs
@@ -145,7 +145,7 @@ async fn run() -> anyhow::Result<()> {
     }
 
     'issues: for issue in tree.iter_issues() {
-        let subtree = tree.subtree_for_issue(issue).expect("TODO");
+        let subtree = tree.subtree_for_issue(issue).expect("issue from tree not found in tree");
         let hash = subtree.stable_hash();
 
         let (bot_comment, _is_new) = issue::find_or_make_bot_comment(&ctx, issue)
diff --git a/techtree-manager/src/tree.rs b/techtree-manager/src/tree.rs
index e3911fc..3ec271f 100644
--- a/techtree-manager/src/tree.rs
+++ b/techtree-manager/src/tree.rs
@@ -165,8 +165,12 @@ impl Tree {
     }
 
     pub fn add_dependency_by_issue_number(&mut self, dependant: u64, dependency: u64) {
-        let a = self.find_element_by_issue_number(dependant).expect("TODO");
-        let b = self.find_element_by_issue_number(dependency).expect("TODO");
+        let a = self
+            .find_element_by_issue_number(dependant)
+            .expect("dependant element does not exist");
+        let b = self
+            .find_element_by_issue_number(dependency)
+            .expect("dependency element does not exist");
         self.graph.add_edge(a, b, ());
     }
 
@@ -422,7 +426,8 @@ impl<'a> Subtree<'a> {
             .collect();
         edges.sort();
 
-        let json_data = serde_json::ser::to_string(&(nodes, edges, HASH_EPOCH)).expect("TODO");
+        let json_data = serde_json::ser::to_string(&(nodes, edges, HASH_EPOCH))
+            .expect("serialization for a stable hash failed");
         sha256::digest(json_data)
     }
 }