diff --git a/src/db.rs b/src/db.rs
index cfb416c..5ceb9dd 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -30,8 +30,6 @@ fn encode_volumes(v: &[String]) -> String {
     serde_json::to_string(v).unwrap()
 }
 
-/// Pure: compute exclusive upper bound for prefix range queries.
-/// Increments the last byte that isn't 0xFF.
 /// Examples: "abc" -> Some("abd"), "ab\xff" -> Some("ac"), "\xff\xff" -> None
 pub fn prefix_upper_bound(prefix: &str) -> Option<String> {
     let mut bytes = prefix.as_bytes().to_vec();
@@ -44,7 +42,6 @@ pub fn prefix_upper_bound(prefix: &str) -> Option<String> {
     None
 }
 
-/// A single SQLite connection behind a mutex, used for both reads and writes.
 #[derive(Clone)]
 pub struct Db {
     conn: Arc<Mutex<Connection>>,
@@ -207,19 +204,17 @@ mod tests {
 
     #[test]
     fn test_prefix_upper_bound_range_correctness() {
-        // The only test that matters: does the bound actually work for range queries?
-        // All strings starting with "foo" should be >= "foo" and < upper_bound("foo")
         let prefix = "foo";
         let upper = prefix_upper_bound(prefix).unwrap();
         let upper = upper.as_str();
 
-        // These should be in range [prefix, upper)
+        // in range [prefix, upper)
         assert!("foo" >= prefix && "foo" < upper);
         assert!("foo/bar" >= prefix && "foo/bar" < upper);
         assert!("foobar" >= prefix && "foobar" < upper);
-        assert!("foo\x7f" >= prefix && "foo\x7f" < upper); // high ASCII
+        assert!("foo\x7f" >= prefix && "foo\x7f" < upper);
 
-        // These should be out of range
+        // out of range
         assert!("fop" >= upper);
         assert!("fon" < prefix);
     }
diff --git a/src/rebuild.rs b/src/rebuild.rs
index 33d4ec2..ddea3e7 100644
--- a/src/rebuild.rs
+++ b/src/rebuild.rs
@@ -12,9 +12,7 @@ struct NginxEntry {
     size: Option<i64>,
 }
 
-/// Pure: merge volume scan results into a unified index.
-/// Each scan is (volume_url, list of (key, size) pairs).
-/// Returns a map of key -> (volumes containing it, max size seen).
+/// If a key has different sizes across volumes, takes the max.
 pub fn merge_volume_scans(
     scans: &[(String, Vec<(String, i64)>)],
 ) -> HashMap<String, (Vec<String>, i64)> {
@@ -77,7 +75,6 @@ pub async fn run(args: &Args) {
 
     let db = db::Db::new(db_path);
 
-    // I/O: scan each volume
     let mut scans = Vec::new();
     for vol_url in &args.volumes {
         eprintln!("Scanning {vol_url}...");
@@ -90,7 +87,6 @@ pub async fn run(args: &Args) {
         }
     }
 
-    // Pure: merge scan results
     let index = merge_volume_scans(&scans);
 
     let records: Vec<_> = index
@@ -108,9 +104,7 @@ mod tests {
 
     #[test]
     fn test_merge_takes_max_size() {
-        // Edge case: same key with different sizes across volumes
-        // (can happen due to incomplete writes or corruption)
-        // We take the max size as the authoritative value
+        // Can happen due to incomplete writes or corruption
         let scans = vec![
             ("http://vol1".to_string(), vec![("key".to_string(), 50)]),
             ("http://vol2".to_string(), vec![("key".to_string(), 200)]),
diff --git a/src/server.rs b/src/server.rs
index 1fd8923..c251b1b 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -15,17 +15,12 @@ pub struct AppState {
     pub http: reqwest::Client,
 }
 
-/// Result of probing volumes for a key.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ProbeResult {
-    /// Found a healthy volume at this URL
     Found(String),
-    /// All volumes were probed, none healthy
     AllFailed,
 }
 
-/// Pure function: given volumes and their probe results (true = healthy),
-/// returns the first healthy volume URL for the key, or None.
 pub fn first_healthy_volume(key: &str, volumes: &[String], results: &[bool]) -> ProbeResult {
     for (vol, &healthy) in volumes.iter().zip(results) {
         if healthy {
@@ -35,8 +30,6 @@ pub fn first_healthy_volume(key: &str, volumes: &[String], results: &[bool]) ->
     ProbeResult::AllFailed
 }
 
-/// Pure function: shuffle volumes for load balancing.
-/// Takes a seed for deterministic testing.
 pub fn shuffle_volumes(volumes: Vec<String>, seed: u64) -> Vec<String> {
     use rand::seq::SliceRandom;
     use rand::SeedableRng;
@@ -55,14 +48,12 @@ pub async fn get_key(
         return Err(AppError::CorruptRecord { key });
     }
 
-    // Shuffle for load balancing (random seed in production)
     let seed = std::time::SystemTime::now()
         .duration_since(std::time::UNIX_EPOCH)
         .map(|d| d.as_nanos() as u64)
         .unwrap_or(0);
     let volumes = shuffle_volumes(record.volumes, seed);
 
-    // Probe volumes and collect results
     let mut results = Vec::with_capacity(volumes.len());
     for vol in &volumes {
         let url = format!("{vol}/{key}");
@@ -78,7 +69,6 @@ pub async fn get_key(
             }
         };
         results.push(healthy);
-        // Early exit on first healthy volume
         if healthy {
             break;
         }
@@ -107,7 +97,6 @@ pub async fn put_key(
         });
     }
 
-    // Fan out PUTs to all target volumes concurrently
     let mut handles = Vec::with_capacity(target_volumes.len());
     for vol in &target_volumes {
         let url = format!("{vol}/{key}");
@@ -243,7 +232,3 @@ pub async fn list_keys(
     Ok((StatusCode::OK, keys.join("\n")).into_response())
 }
 
-// Note: first_healthy_volume and shuffle_volumes are trivial functions
-// (essentially .find() and .shuffle()). Testing them would just test
-// that standard library functions work. The real test is integration:
-// does failover work with actual down volumes?