diff --git a/crates/walgit-config/src/lib.rs b/crates/walgit-config/src/lib.rs
index e3cdaf15..dbea88f5 100644
--- a/crates/walgit-config/src/lib.rs
+++ b/crates/walgit-config/src/lib.rs
@@ -1079,6 +1079,10 @@ impl Config {
     pub fn validate(&self) -> Result<()> {
         self.refs.validate()?;
         self.packs.validate()?;
+        anyhow::ensure!(
+            self.server.max_concurrent_per_repo > 0,
+            "server.max_concurrent_per_repo must be positive"
+        );
         anyhow::ensure!(
             self.packfile_uri.uri_min_bytes.as_u64() > 0,
             "packfile_uri.uri_min_bytes must be positive"
@@ -1354,6 +1358,14 @@ mod tests {
         assert_eq!(back.store.bucket, c.store.bucket);
     }
 
+    #[test]
+    fn zero_per_repo_concurrency_is_rejected() {
+        let mut c = Config::default();
+        c.server.max_concurrent_per_repo = 0;
+        let err = c.validate().unwrap_err().to_string();
+        assert!(err.contains("server.max_concurrent_per_repo must be positive"));
+    }
+
     #[test]
     fn example_configurations_parse_and_validate() {
         Config::parse(include_str!("../../../walgit.example.toml")).unwrap();