diff --git a/crates/goose-bench/src/runners/eval_runner.rs b/crates/goose-bench/src/runners/eval_runner.rs
index 57bebc44..09c4259a 100644
--- a/crates/goose-bench/src/runners/eval_runner.rs
+++ b/crates/goose-bench/src/runners/eval_runner.rs
@@ -9,6 +9,7 @@ use std::fs;
 use std::future::Future;
 use std::path::PathBuf;
 use std::process::Command;
+use std::time::{SystemTime, UNIX_EPOCH};
 
 #[derive(Clone)]
 pub struct EvalRunner {
@@ -66,7 +67,8 @@ impl EvalRunner {
         work_dir.set_eval(&bench_eval.selector, run_id);
 
         if let Some(eval) = EvaluationSuite::from(&bench_eval.selector) {
-            let session_id = bench_eval.selector.clone();
+            let now_stamp = SystemTime::now().duration_since(UNIX_EPOCH)?.as_nanos();
+            let session_id = format!("{}-{}", bench_eval.selector.clone(), now_stamp);
             let mut agent = agent_generator(eval.required_extensions(), session_id).await;
 
             let mut result = EvaluationResult::new(eval.name().to_string());