diff --git a/desktop/src-tauri/src/managed_agents/session_policy.rs b/desktop/src-tauri/src/managed_agents/session_policy.rs
index fe4251761b..6c903860d9 100644
--- a/desktop/src-tauri/src/managed_agents/session_policy.rs
+++ b/desktop/src-tauri/src/managed_agents/session_policy.rs
@@ -67,6 +67,14 @@ pub(crate) fn acp_session_policy(state: &AppState) -> AcpSessionPolicy {
     )
 }
 
+/// Apply the captured launch policy after inherited and user environment.
+pub(crate) fn apply_acp_session_policy_env(
+    command: &mut std::process::Command,
+    policy: AcpSessionPolicy,
+) {
+    command.env(ACP_SESSION_POLICY_ENV_VAR, policy.as_str());
+}
+
 pub(crate) fn insert_acp_session_policy_env(
     policy_env: &mut BTreeMap<String, String>,
     policy: AcpSessionPolicy,
@@ -118,4 +126,14 @@ mod tests {
 
         assert_eq!(command_policy(&command), Some("thread"));
     }
+
+    #[test]
+    fn captured_local_policy_overrides_user_env_without_reading_live_state() {
+        for policy in [AcpSessionPolicy::Channel, AcpSessionPolicy::Thread] {
+            let mut command = std::process::Command::new("true");
+            command.env(ACP_SESSION_POLICY_ENV_VAR, "ambient");
+            apply_acp_session_policy_env(&mut command, policy);
+            assert_eq!(command_policy(&command), Some(policy.as_str()));
+        }
+    }
 }