diff --git a/codex-rs/core/src/agent/control.rs b/codex-rs/core/src/agent/control.rs
index 10cbd441b48..d2a7cbf9db8 100644
--- a/codex-rs/core/src/agent/control.rs
+++ b/codex-rs/core/src/agent/control.rs
@@ -1,6 +1,6 @@
 use crate::agent::AgentStatus;
-use crate::agent::guards::AgentMetadata;
-use crate::agent::guards::Guards;
+use crate::agent::registry::AgentMetadata;
+use crate::agent::registry::AgentRegistry;
 use crate::agent::role::DEFAULT_ROLE_NAME;
 use crate::agent::role::resolve_role_config;
 use crate::agent::status::is_final;
@@ -80,14 +80,14 @@ fn agent_nickname_candidates(
 /// spawn new agents and the inter-agent communication layer.
 /// An `AgentControl` instance is intended to be created at most once per root thread/session
 /// tree. That same `AgentControl` is then shared with every sub-agent spawned from that root,
-/// which keeps the guards scoped to that root thread rather than the entire `ThreadManager`.
+/// which keeps the registry scoped to that root thread rather than the entire `ThreadManager`.
 #[derive(Clone, Default)]
 pub(crate) struct AgentControl {
     /// Weak handle back to the global thread registry/state.
     /// This is `Weak` to avoid reference cycles and shadow persistence of the form
     /// `ThreadManagerState -> CodexThread -> Session -> SessionServices -> ThreadManagerState`.
     manager: Weak<ThreadManagerState>,
-    state: Arc<Guards>,
+    state: Arc<AgentRegistry>,
 }
 
 impl AgentControl {
@@ -686,7 +686,7 @@ impl AgentControl {
     #[allow(clippy::too_many_arguments)]
     fn prepare_thread_spawn(
         &self,
-        reservation: &mut crate::agent::guards::SpawnReservation,
+        reservation: &mut crate::agent::registry::SpawnReservation,
         config: &crate::config::Config,
         parent_thread_id: ThreadId,
         depth: i32,
diff --git a/codex-rs/core/src/agent/mod.rs b/codex-rs/core/src/agent/mod.rs
index 681f993a943..350962dc081 100644
--- a/codex-rs/core/src/agent/mod.rs
+++ b/codex-rs/core/src/agent/mod.rs
@@ -1,11 +1,11 @@
 pub(crate) mod agent_resolver;
 pub(crate) mod control;
-mod guards;
+mod registry;
 pub(crate) mod role;
 pub(crate) mod status;
 
 pub(crate) use codex_protocol::protocol::AgentStatus;
 pub(crate) use control::AgentControl;
-pub(crate) use guards::exceeds_thread_spawn_depth_limit;
-pub(crate) use guards::next_thread_spawn_depth;
+pub(crate) use registry::exceeds_thread_spawn_depth_limit;
+pub(crate) use registry::next_thread_spawn_depth;
 pub(crate) use status::agent_status_from_event;
diff --git a/codex-rs/core/src/agent/guards.rs b/codex-rs/core/src/agent/registry.rs
similarity index 98%
rename from codex-rs/core/src/agent/guards.rs
rename to codex-rs/core/src/agent/registry.rs
index 665c02ebfbe..af545e8c97c 100644
--- a/codex-rs/core/src/agent/guards.rs
+++ b/codex-rs/core/src/agent/registry.rs
@@ -20,7 +20,7 @@ use std::sync::atomic::Ordering;
 /// This structure is shared by all agents in the same user session (because the `AgentControl`
 /// is).
 #[derive(Default)]
-pub(crate) struct Guards {
+pub(crate) struct AgentRegistry {
     active_agents: Mutex<ActiveAgents>,
     total_count: AtomicUsize,
 }
@@ -75,7 +75,7 @@ pub(crate) fn exceeds_thread_spawn_depth_limit(depth: i32, max_depth: i32) -> bo
     depth > max_depth
 }
 
-impl Guards {
+impl AgentRegistry {
     pub(crate) fn reserve_spawn_slot(
         self: &Arc<Self>,
         max_threads: Option<usize>,
@@ -263,7 +263,7 @@ impl Guards {
 }
 
 pub(crate) struct SpawnReservation {
-    state: Arc<Guards>,
+    state: Arc<AgentRegistry>,
     active: bool,
     reserved_agent_nickname: Option<String>,
     reserved_agent_path: Option<AgentPath>,
@@ -311,5 +311,5 @@ impl Drop for SpawnReservation {
 }
 
 #[cfg(test)]
-#[path = "guards_tests.rs"]
+#[path = "registry_tests.rs"]
 mod tests;
diff --git a/codex-rs/core/src/agent/guards_tests.rs b/codex-rs/core/src/agent/registry_tests.rs
similarity index 70%
rename from codex-rs/core/src/agent/guards_tests.rs
rename to codex-rs/core/src/agent/registry_tests.rs
index 9da4cec8487..43d91952a7c 100644
--- a/codex-rs/core/src/agent/guards_tests.rs
+++ b/codex-rs/core/src/agent/registry_tests.rs
@@ -52,22 +52,22 @@ fn non_thread_spawn_subagents_default_to_depth_zero() {
 
 #[test]
 fn reservation_drop_releases_slot() {
-    let guards = Arc::new(Guards::default());
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("reserve slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("reserve slot");
     drop(reservation);
 
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("slot released");
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("slot released");
     drop(reservation);
 }
 
 #[test]
 fn commit_holds_slot_until_release() {
-    let guards = Arc::new(Guards::default());
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("reserve slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("reserve slot");
     let thread_id = ThreadId::new();
     reservation.commit(agent_metadata(thread_id));
 
-    let err = match guards.reserve_spawn_slot(Some(1)) {
+    let err = match registry.reserve_spawn_slot(Some(1)) {
         Ok(_) => panic!("limit should be enforced"),
         Err(err) => err,
     };
@@ -76,8 +76,8 @@ fn commit_holds_slot_until_release() {
     };
     assert_eq!(max_threads, 1);
 
-    guards.release_spawned_thread(thread_id);
-    let reservation = guards
+    registry.release_spawned_thread(thread_id);
+    let reservation = registry
         .reserve_spawn_slot(Some(1))
         .expect("slot released after thread removal");
     drop(reservation);
@@ -85,14 +85,14 @@ fn commit_holds_slot_until_release() {
 
 #[test]
 fn release_ignores_unknown_thread_id() {
-    let guards = Arc::new(Guards::default());
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("reserve slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("reserve slot");
     let thread_id = ThreadId::new();
     reservation.commit(agent_metadata(thread_id));
 
-    guards.release_spawned_thread(ThreadId::new());
+    registry.release_spawned_thread(ThreadId::new());
 
-    let err = match guards.reserve_spawn_slot(Some(1)) {
+    let err = match registry.reserve_spawn_slot(Some(1)) {
         Ok(_) => panic!("limit should still be enforced"),
         Err(err) => err,
     };
@@ -101,8 +101,8 @@ fn release_ignores_unknown_thread_id() {
     };
     assert_eq!(max_threads, 1);
 
-    guards.release_spawned_thread(thread_id);
-    let reservation = guards
+    registry.release_spawned_thread(thread_id);
+    let reservation = registry
         .reserve_spawn_slot(Some(1))
         .expect("slot released after real thread removal");
     drop(reservation);
@@ -110,20 +110,20 @@ fn release_ignores_unknown_thread_id() {
 
 #[test]
 fn release_is_idempotent_for_registered_threads() {
-    let guards = Arc::new(Guards::default());
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("reserve slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("reserve slot");
     let first_id = ThreadId::new();
     reservation.commit(agent_metadata(first_id));
 
-    guards.release_spawned_thread(first_id);
+    registry.release_spawned_thread(first_id);
 
-    let reservation = guards.reserve_spawn_slot(Some(1)).expect("slot reused");
+    let reservation = registry.reserve_spawn_slot(Some(1)).expect("slot reused");
     let second_id = ThreadId::new();
     reservation.commit(agent_metadata(second_id));
 
-    guards.release_spawned_thread(first_id);
+    registry.release_spawned_thread(first_id);
 
-    let err = match guards.reserve_spawn_slot(Some(1)) {
+    let err = match registry.reserve_spawn_slot(Some(1)) {
         Ok(_) => panic!("limit should still be enforced"),
         Err(err) => err,
     };
@@ -132,8 +132,8 @@ fn release_is_idempotent_for_registered_threads() {
     };
     assert_eq!(max_threads, 1);
 
-    guards.release_spawned_thread(second_id);
-    let reservation = guards
+    registry.release_spawned_thread(second_id);
+    let reservation = registry
         .reserve_spawn_slot(Some(1))
         .expect("slot released after second thread removal");
     drop(reservation);
@@ -141,15 +141,15 @@ fn release_is_idempotent_for_registered_threads() {
 
 #[test]
 fn failed_spawn_keeps_nickname_marked_used() {
-    let guards = Arc::new(Guards::default());
-    let mut reservation = guards.reserve_spawn_slot(None).expect("reserve slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let mut reservation = registry.reserve_spawn_slot(None).expect("reserve slot");
     let agent_nickname = reservation
         .reserve_agent_nickname_with_preference(&["alpha"], /*preferred*/ None)
         .expect("reserve agent name");
     assert_eq!(agent_nickname, "alpha");
     drop(reservation);
 
-    let mut reservation = guards.reserve_spawn_slot(None).expect("reserve slot");
+    let mut reservation = registry.reserve_spawn_slot(None).expect("reserve slot");
     let agent_nickname = reservation
         .reserve_agent_nickname_with_preference(&["alpha", "beta"], /*preferred*/ None)
         .expect("unused name should still be preferred");
@@ -158,8 +158,10 @@ fn failed_spawn_keeps_nickname_marked_used() {
 
 #[test]
 fn agent_nickname_resets_used_pool_when_exhausted() {
-    let guards = Arc::new(Guards::default());
-    let mut first = guards.reserve_spawn_slot(None).expect("reserve first slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let mut first = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve first slot");
     let first_name = first
         .reserve_agent_nickname_with_preference(&["alpha"], /*preferred*/ None)
         .expect("reserve first agent name");
@@ -167,14 +169,14 @@ fn agent_nickname_resets_used_pool_when_exhausted() {
     first.commit(agent_metadata(first_id));
     assert_eq!(first_name, "alpha");
 
-    let mut second = guards
+    let mut second = registry
         .reserve_spawn_slot(None)
         .expect("reserve second slot");
     let second_name = second
         .reserve_agent_nickname_with_preference(&["alpha"], /*preferred*/ None)
         .expect("name should be reused after pool reset");
     assert_eq!(second_name, "alpha the 2nd");
-    let active_agents = guards
+    let active_agents = registry
         .active_agents
         .lock()
         .unwrap_or_else(std::sync::PoisonError::into_inner);
@@ -183,9 +185,11 @@ fn agent_nickname_resets_used_pool_when_exhausted() {
 
 #[test]
 fn released_nickname_stays_used_until_pool_reset() {
-    let guards = Arc::new(Guards::default());
+    let registry = Arc::new(AgentRegistry::default());
 
-    let mut first = guards.reserve_spawn_slot(None).expect("reserve first slot");
+    let mut first = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve first slot");
     let first_name = first
         .reserve_agent_nickname_with_preference(&["alpha"], /*preferred*/ None)
         .expect("reserve first agent name");
@@ -193,9 +197,9 @@ fn released_nickname_stays_used_until_pool_reset() {
     first.commit(agent_metadata(first_id));
     assert_eq!(first_name, "alpha");
 
-    guards.release_spawned_thread(first_id);
+    registry.release_spawned_thread(first_id);
 
-    let mut second = guards
+    let mut second = registry
         .reserve_spawn_slot(None)
         .expect("reserve second slot");
     let second_name = second
@@ -204,15 +208,17 @@ fn released_nickname_stays_used_until_pool_reset() {
     assert_eq!(second_name, "beta");
     let second_id = ThreadId::new();
     second.commit(agent_metadata(second_id));
-    guards.release_spawned_thread(second_id);
+    registry.release_spawned_thread(second_id);
 
-    let mut third = guards.reserve_spawn_slot(None).expect("reserve third slot");
+    let mut third = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve third slot");
     let third_name = third
         .reserve_agent_nickname_with_preference(&["alpha", "beta"], /*preferred*/ None)
         .expect("pool reset should permit a duplicate");
     let expected_names = HashSet::from(["alpha the 2nd".to_string(), "beta the 2nd".to_string()]);
     assert!(expected_names.contains(&third_name));
-    let active_agents = guards
+    let active_agents = registry
         .active_agents
         .lock()
         .unwrap_or_else(std::sync::PoisonError::into_inner);
@@ -221,18 +227,20 @@ fn released_nickname_stays_used_until_pool_reset() {
 
 #[test]
 fn repeated_resets_advance_the_ordinal_suffix() {
-    let guards = Arc::new(Guards::default());
+    let registry = Arc::new(AgentRegistry::default());
 
-    let mut first = guards.reserve_spawn_slot(None).expect("reserve first slot");
+    let mut first = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve first slot");
     let first_name = first
         .reserve_agent_nickname_with_preference(&["Plato"], /*preferred*/ None)
         .expect("reserve first agent name");
     let first_id = ThreadId::new();
     first.commit(agent_metadata(first_id));
     assert_eq!(first_name, "Plato");
-    guards.release_spawned_thread(first_id);
+    registry.release_spawned_thread(first_id);
 
-    let mut second = guards
+    let mut second = registry
         .reserve_spawn_slot(None)
         .expect("reserve second slot");
     let second_name = second
@@ -241,14 +249,16 @@ fn repeated_resets_advance_the_ordinal_suffix() {
     let second_id = ThreadId::new();
     second.commit(agent_metadata(second_id));
     assert_eq!(second_name, "Plato the 2nd");
-    guards.release_spawned_thread(second_id);
+    registry.release_spawned_thread(second_id);
 
-    let mut third = guards.reserve_spawn_slot(None).expect("reserve third slot");
+    let mut third = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve third slot");
     let third_name = third
         .reserve_agent_nickname_with_preference(&["Plato"], /*preferred*/ None)
         .expect("reserve third agent name");
     assert_eq!(third_name, "Plato the 3rd");
-    let active_agents = guards
+    let active_agents = registry
         .active_agents
         .lock()
         .unwrap_or_else(std::sync::PoisonError::into_inner);
@@ -257,27 +267,29 @@ fn repeated_resets_advance_the_ordinal_suffix() {
 
 #[test]
 fn register_root_thread_indexes_root_path() {
-    let guards = Arc::new(Guards::default());
+    let registry = Arc::new(AgentRegistry::default());
     let root_thread_id = ThreadId::new();
 
-    guards.register_root_thread(root_thread_id);
+    registry.register_root_thread(root_thread_id);
 
     assert_eq!(
-        guards.agent_id_for_path(&AgentPath::root()),
+        registry.agent_id_for_path(&AgentPath::root()),
         Some(root_thread_id)
     );
 }
 
 #[test]
 fn reserved_agent_path_is_released_when_spawn_fails() {
-    let guards = Arc::new(Guards::default());
-    let mut first = guards.reserve_spawn_slot(None).expect("reserve first slot");
+    let registry = Arc::new(AgentRegistry::default());
+    let mut first = registry
+        .reserve_spawn_slot(None)
+        .expect("reserve first slot");
     first
         .reserve_agent_path(&agent_path("/root/researcher"))
         .expect("reserve first path");
     drop(first);
 
-    let mut second = guards
+    let mut second = registry
         .reserve_spawn_slot(None)
         .expect("reserve second slot");
     second
@@ -287,9 +299,9 @@ fn reserved_agent_path_is_released_when_spawn_fails() {
 
 #[test]
 fn committed_agent_path_is_indexed_until_release() {
-    let guards = Arc::new(Guards::default());
+    let registry = Arc::new(AgentRegistry::default());
     let thread_id = ThreadId::new();
-    let mut reservation = guards.reserve_spawn_slot(None).expect("reserve slot");
+    let mut reservation = registry.reserve_spawn_slot(None).expect("reserve slot");
     reservation
         .reserve_agent_path(&agent_path("/root/researcher"))
         .expect("reserve path");
@@ -300,13 +312,13 @@ fn committed_agent_path_is_indexed_until_release() {
     });
 
     assert_eq!(
-        guards.agent_id_for_path(&agent_path("/root/researcher")),
+        registry.agent_id_for_path(&agent_path("/root/researcher")),
         Some(thread_id)
     );
 
-    guards.release_spawned_thread(thread_id);
+    registry.release_spawned_thread(thread_id);
     assert_eq!(
-        guards.agent_id_for_path(&agent_path("/root/researcher")),
+        registry.agent_id_for_path(&agent_path("/root/researcher")),
         None
     );
 }