diff --git a/codex-rs/core/src/tools/runtimes/unified_exec.rs b/codex-rs/core/src/tools/runtimes/unified_exec.rs
index ed813f3f27..2a4c29fd01 100644
--- a/codex-rs/core/src/tools/runtimes/unified_exec.rs
+++ b/codex-rs/core/src/tools/runtimes/unified_exec.rs
@@ -103,6 +103,13 @@ pub struct UnifiedExecRuntime<'a> {
     shell_mode: UnifiedExecShellMode,
 }
 
+/// Lifecycle callback surface that lets unified exec mirror its generic spawn
+/// lifecycle into a resolved plugin-script execution.
+///
+/// Implementations must preserve the caller-provided callback order: unified
+/// exec invokes the generic `SpawnLifecycle` first, then forwards the matching
+/// plugin callback. Terminal callbacks may be repeated by cleanup paths, so
+/// implementations must keep cancellation and finish handling idempotent.
 trait PluginScriptLifecycle: Send + Sync {
     fn mark_started(&self);
     fn mark_cancelled(&self);
@@ -935,7 +942,7 @@ mod tests {
                 proposed_execpolicy_amendment: None,
             },
         );
-        request.environment = Arc::new(
+        request.turn_environment.environment = Arc::new(
             Environment::create_for_tests(Some("ws://127.0.0.1:1/remote-exec-server".to_string()))
                 .expect("remote environment"),
         );