diff --git a/src/ed25519.rs b/src/ed25519.rs
index 0b55f58..4942e6b 100644
--- a/src/ed25519.rs
+++ b/src/ed25519.rs
@@ -12,8 +12,12 @@ static ED25519AGENT: LazyLock<Vec<Mutex<Agent>>> = LazyLock::new(|| {
         .expect("ED25519_AGENT_PATH environment variable missing");
     let keyfile_path =
         std::env::var("ED25519_KEYFILE").expect("Ed25519_KEYFILE environment variable missing");
-    let mut agents = Vec::with_capacity(5);
-    for _ in 0..5 {
+    let num_agents: usize = std::env::var("NUM_AGENTS")
+        .expect("NUM_AGENTS environment variable missing")
+        .parse()
+        .expect("NUM_AGENTS should be an integer");
+    let mut agents = Vec::with_capacity(num_agents);
+    for _ in 0..num_agents {
         let agent = unsafe {
             Agent::new(Path::new(&agent_path), Path::new(&keyfile_path))
                 .expect("Agent failed to start")