diff --git a/codex-rs/core/src/tools/handlers/multi_agents_tests.rs b/codex-rs/core/src/tools/handlers/multi_agents_tests.rs
index 4fe6ac0e9..ee81b961e 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_tests.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_tests.rs
@@ -9,8 +9,8 @@ use crate::state::TaskKind;
 use crate::tasks::SessionTask;
 use crate::tasks::SessionTaskContext;
 use crate::tools::context::ToolOutput;
-use crate::tools::handlers::multi_agents_v2::AssignTaskHandler as AssignTaskHandlerV2;
 use crate::tools::handlers::multi_agents_v2::CloseAgentHandler as CloseAgentHandlerV2;
+use crate::tools::handlers::multi_agents_v2::FollowupTaskHandler as FollowupTaskHandlerV2;
 use crate::tools::handlers::multi_agents_v2::ListAgentsHandler as ListAgentsHandlerV2;
 use crate::tools::handlers::multi_agents_v2::SendMessageHandler as SendMessageHandlerV2;
 use crate::tools::handlers::multi_agents_v2::SpawnAgentHandler as SpawnAgentHandlerV2;
@@ -710,7 +710,7 @@ async fn multi_agent_v2_send_message_accepts_root_target_from_child() {
 }
 
 #[tokio::test]
-async fn multi_agent_v2_assign_task_rejects_root_target_from_child() {
+async fn multi_agent_v2_followup_task_rejects_root_target_from_child() {
     let (mut session, mut turn) = make_session_and_context().await;
     let manager = thread_manager();
     let root = manager
@@ -758,11 +758,11 @@ async fn multi_agent_v2_assign_task_rejects_root_target_from_child() {
         agent_role: None,
     });
 
-    let err = AssignTaskHandlerV2
+    let err = FollowupTaskHandlerV2
         .handle(invocation(
             Arc::new(session),
             Arc::new(turn),
-            "assign_task",
+            "followup_task",
             function_payload(json!({
                 "target": "/root",
                 "message": "run this",
@@ -770,7 +770,7 @@ async fn multi_agent_v2_assign_task_rejects_root_target_from_child() {
             })),
         ))
         .await
-        .expect_err("assign_task should reject the root target");
+        .expect_err("followup_task should reject the root target");
 
     assert_eq!(
         err,
@@ -1161,7 +1161,7 @@ async fn multi_agent_v2_send_message_rejects_interrupt_parameter() {
 }
 
 #[tokio::test]
-async fn multi_agent_v2_assign_task_interrupts_busy_child_without_losing_message() {
+async fn multi_agent_v2_followup_task_interrupts_busy_child_without_losing_message() {
     let (mut session, mut turn) = make_session_and_context().await;
     let manager = thread_manager();
     let root = manager
@@ -1213,11 +1213,11 @@ async fn multi_agent_v2_assign_task_interrupts_busy_child_without_losing_message
         )
         .await;
 
-    AssignTaskHandlerV2
+    FollowupTaskHandlerV2
         .handle(invocation(
             session,
             turn,
-            "assign_task",
+            "followup_task",
             function_payload(json!({
                 "target": agent_id.to_string(),
                 "message": "continue",
@@ -1225,7 +1225,7 @@ async fn multi_agent_v2_assign_task_interrupts_busy_child_without_losing_message
             })),
         ))
         .await
-        .expect("interrupting v2 assign_task should succeed");
+        .expect("interrupting v2 followup_task should succeed");
 
     let ops = manager.captured_ops();
     let ops_for_agent: Vec<&Op> = ops
@@ -1281,7 +1281,7 @@ async fn multi_agent_v2_assign_task_interrupts_busy_child_without_losing_message
         }
     })
     .await
-    .expect("interrupting v2 assign_task should preserve the redirected message");
+    .expect("interrupting v2 followup_task should preserve the redirected message");
 
     let _ = thread
         .submit(Op::Shutdown {})
@@ -1290,7 +1290,7 @@ async fn multi_agent_v2_assign_task_interrupts_busy_child_without_losing_message
 }
 
 #[tokio::test]
-async fn multi_agent_v2_assign_task_completion_notifies_parent_on_every_turn() {
+async fn multi_agent_v2_followup_task_completion_notifies_parent_on_every_turn() {
     let (mut session, mut turn) = make_session_and_context().await;
     let manager = thread_manager();
     let root = manager
@@ -1342,18 +1342,18 @@ async fn multi_agent_v2_assign_task_completion_notifies_parent_on_every_turn() {
         )
         .await;
 
-    AssignTaskHandlerV2
+    FollowupTaskHandlerV2
         .handle(invocation(
             session,
             turn,
-            "assign_task",
+            "followup_task",
             function_payload(json!({
                 "target": agent_id.to_string(),
                 "message": "continue",
             })),
         ))
         .await
-        .expect("assign_task should succeed");
+        .expect("followup_task should succeed");
 
     let second_turn = thread.codex.session.new_default_turn().await;
     thread
@@ -1419,7 +1419,7 @@ async fn multi_agent_v2_assign_task_completion_notifies_parent_on_every_turn() {
 }
 
 #[tokio::test]
-async fn multi_agent_v2_assign_task_rejects_legacy_items_field() {
+async fn multi_agent_v2_followup_task_rejects_legacy_items_field() {
     let (mut session, mut turn) = make_session_and_context().await;
     let manager = thread_manager();
     let root = manager
@@ -1455,14 +1455,14 @@ async fn multi_agent_v2_assign_task_rejects_legacy_items_field() {
     let invocation = invocation(
         session,
         turn,
-        "assign_task",
+        "followup_task",
         function_payload(json!({
             "target": agent_id.to_string(),
             "items": [{"type": "text", "text": "continue"}],
         })),
     );
 
-    let Err(err) = AssignTaskHandlerV2.handle(invocation).await else {
+    let Err(err) = FollowupTaskHandlerV2.handle(invocation).await else {
         panic!("legacy items field should be rejected in v2");
     };
     let FunctionCallError::RespondToModel(message) = err else {
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2.rs
index e572ec0af..44191ed85 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2.rs
@@ -28,15 +28,15 @@ use serde::Deserialize;
 use serde::Serialize;
 use serde_json::Value as JsonValue;
 
-pub(crate) use assign_task::Handler as AssignTaskHandler;
 pub(crate) use close_agent::Handler as CloseAgentHandler;
+pub(crate) use followup_task::Handler as FollowupTaskHandler;
 pub(crate) use list_agents::Handler as ListAgentsHandler;
 pub(crate) use send_message::Handler as SendMessageHandler;
 pub(crate) use spawn::Handler as SpawnAgentHandler;
 pub(crate) use wait::Handler as WaitAgentHandler;
 
-mod assign_task;
 mod close_agent;
+mod followup_task;
 mod list_agents;
 mod message_tool;
 mod send_message;
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/assign_task.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
similarity index 88%
rename from codex-rs/core/src/tools/handlers/multi_agents_v2/assign_task.rs
rename to codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
index c55c25d05..d0f87f342 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/assign_task.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs
@@ -1,4 +1,4 @@
-use super::message_tool::AssignTaskArgs;
+use super::message_tool::FollowupTaskArgs;
 use super::message_tool::MessageDeliveryMode;
 use super::message_tool::MessageToolResult;
 use super::message_tool::handle_message_string_tool;
@@ -20,7 +20,7 @@ impl ToolHandler for Handler {
 
     async fn handle(&self, invocation: ToolInvocation) -> Result<Self::Output, FunctionCallError> {
         let arguments = function_arguments(invocation.payload.clone())?;
-        let args: AssignTaskArgs = parse_arguments(&arguments)?;
+        let args: FollowupTaskArgs = parse_arguments(&arguments)?;
         handle_message_string_tool(
             invocation,
             MessageDeliveryMode::TriggerTurn,
diff --git a/codex-rs/core/src/tools/handlers/multi_agents_v2/message_tool.rs b/codex-rs/core/src/tools/handlers/multi_agents_v2/message_tool.rs
index 62835a12c..3123e93f4 100644
--- a/codex-rs/core/src/tools/handlers/multi_agents_v2/message_tool.rs
+++ b/codex-rs/core/src/tools/handlers/multi_agents_v2/message_tool.rs
@@ -1,6 +1,6 @@
 //! Shared argument parsing and dispatch for the v2 text-only agent messaging tools.
 //!
-//! `send_message` and `assign_task` share the same submission path and differ only in whether the
+//! `send_message` and `followup_task` share the same submission path and differ only in whether the
 //! resulting `InterAgentCommunication` should wake the target immediately.
 
 use super::*;
@@ -38,8 +38,8 @@ pub(crate) struct SendMessageArgs {
 
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
-/// Input for the MultiAgentV2 `assign_task` tool.
-pub(crate) struct AssignTaskArgs {
+/// Input for the MultiAgentV2 `followup_task` tool.
+pub(crate) struct FollowupTaskArgs {
     pub(crate) target: String,
     pub(crate) message: String,
     #[serde(default)]
@@ -79,7 +79,7 @@ fn message_content(message: String) -> Result<String, FunctionCallError> {
     Ok(message)
 }
 
-/// Handles the shared MultiAgentV2 plain-text message flow for both `send_message` and `assign_task`.
+/// Handles the shared MultiAgentV2 plain-text message flow for both `send_message` and `followup_task`.
 pub(crate) async fn handle_message_string_tool(
     invocation: ToolInvocation,
     mode: MessageDeliveryMode,
diff --git a/codex-rs/core/src/tools/spec.rs b/codex-rs/core/src/tools/spec.rs
index 341db2476..90b9a382a 100644
--- a/codex-rs/core/src/tools/spec.rs
+++ b/codex-rs/core/src/tools/spec.rs
@@ -60,8 +60,8 @@ pub(crate) fn build_specs_with_discoverable_tools(
     use crate::tools::handlers::multi_agents::SendInputHandler;
     use crate::tools::handlers::multi_agents::SpawnAgentHandler;
     use crate::tools::handlers::multi_agents::WaitAgentHandler;
-    use crate::tools::handlers::multi_agents_v2::AssignTaskHandler as AssignTaskHandlerV2;
     use crate::tools::handlers::multi_agents_v2::CloseAgentHandler as CloseAgentHandlerV2;
+    use crate::tools::handlers::multi_agents_v2::FollowupTaskHandler as FollowupTaskHandlerV2;
     use crate::tools::handlers::multi_agents_v2::ListAgentsHandler as ListAgentsHandlerV2;
     use crate::tools::handlers::multi_agents_v2::SendMessageHandler as SendMessageHandlerV2;
     use crate::tools::handlers::multi_agents_v2::SpawnAgentHandler as SpawnAgentHandlerV2;
@@ -136,9 +136,6 @@ pub(crate) fn build_specs_with_discoverable_tools(
             ToolHandlerKind::ApplyPatch => {
                 builder.register_handler(handler.name, apply_patch_handler.clone());
             }
-            ToolHandlerKind::AssignTaskV2 => {
-                builder.register_handler(handler.name, Arc::new(AssignTaskHandlerV2));
-            }
             ToolHandlerKind::CloseAgentV1 => {
                 builder.register_handler(handler.name, Arc::new(CloseAgentHandler));
             }
@@ -154,6 +151,9 @@ pub(crate) fn build_specs_with_discoverable_tools(
             ToolHandlerKind::DynamicTool => {
                 builder.register_handler(handler.name, dynamic_tool_handler.clone());
             }
+            ToolHandlerKind::FollowupTaskV2 => {
+                builder.register_handler(handler.name, Arc::new(FollowupTaskHandlerV2));
+            }
             ToolHandlerKind::JsRepl => {
                 builder.register_handler(handler.name, js_repl_handler.clone());
             }
diff --git a/codex-rs/tools/src/agent_tool.rs b/codex-rs/tools/src/agent_tool.rs
index b82084d51..017cc6e5e 100644
--- a/codex-rs/tools/src/agent_tool.rs
+++ b/codex-rs/tools/src/agent_tool.rs
@@ -150,7 +150,7 @@ pub fn create_send_message_tool() -> ToolSpec {
     })
 }
 
-pub fn create_assign_task_tool() -> ToolSpec {
+pub fn create_followup_task_tool() -> ToolSpec {
     let properties = BTreeMap::from([
         (
             "target".to_string(),
@@ -178,7 +178,7 @@ pub fn create_assign_task_tool() -> ToolSpec {
     ]);
 
     ToolSpec::Function(ResponsesApiTool {
-        name: "assign_task".to_string(),
+        name: "followup_task".to_string(),
         description: "Add a message to an existing non-root agent and trigger a turn in the target. Use interrupt=true to redirect work immediately. In MultiAgentV2, this tool currently supports text content only."
             .to_string(),
         strict: false,
diff --git a/codex-rs/tools/src/agent_tool_tests.rs b/codex-rs/tools/src/agent_tool_tests.rs
index 2277a5ec1..cd68fbd13 100644
--- a/codex-rs/tools/src/agent_tool_tests.rs
+++ b/codex-rs/tools/src/agent_tool_tests.rs
@@ -127,14 +127,14 @@ fn send_message_tool_requires_message_and_uses_submission_output() {
 }
 
 #[test]
-fn assign_task_tool_requires_message_and_uses_submission_output() {
+fn followup_task_tool_requires_message_and_uses_submission_output() {
     let ToolSpec::Function(ResponsesApiTool {
         parameters,
         output_schema,
         ..
-    }) = create_assign_task_tool()
+    }) = create_followup_task_tool()
     else {
-        panic!("assign_task should be a function tool");
+        panic!("followup_task should be a function tool");
     };
     let JsonSchema::Object {
         properties,
@@ -142,7 +142,7 @@ fn assign_task_tool_requires_message_and_uses_submission_output() {
         ..
     } = parameters
     else {
-        panic!("assign_task should use object params");
+        panic!("followup_task should use object params");
     };
     assert!(properties.contains_key("target"));
     assert!(properties.contains_key("message"));
@@ -153,7 +153,7 @@ fn assign_task_tool_requires_message_and_uses_submission_output() {
         Some(vec!["target".to_string(), "message".to_string()])
     );
     assert_eq!(
-        output_schema.expect("assign_task output schema")["required"],
+        output_schema.expect("followup_task output schema")["required"],
         json!(["submission_id"])
     );
 }
diff --git a/codex-rs/tools/src/lib.rs b/codex-rs/tools/src/lib.rs
index 91931e894..16e84700b 100644
--- a/codex-rs/tools/src/lib.rs
+++ b/codex-rs/tools/src/lib.rs
@@ -29,9 +29,9 @@ pub use agent_job_tool::create_report_agent_job_result_tool;
 pub use agent_job_tool::create_spawn_agents_on_csv_tool;
 pub use agent_tool::SpawnAgentToolOptions;
 pub use agent_tool::WaitAgentTimeoutOptions;
-pub use agent_tool::create_assign_task_tool;
 pub use agent_tool::create_close_agent_tool_v1;
 pub use agent_tool::create_close_agent_tool_v2;
+pub use agent_tool::create_followup_task_tool;
 pub use agent_tool::create_list_agents_tool;
 pub use agent_tool::create_resume_agent_tool;
 pub use agent_tool::create_send_input_tool_v1;
diff --git a/codex-rs/tools/src/tool_registry_plan.rs b/codex-rs/tools/src/tool_registry_plan.rs
index 314d93f55..cc706f24f 100644
--- a/codex-rs/tools/src/tool_registry_plan.rs
+++ b/codex-rs/tools/src/tool_registry_plan.rs
@@ -18,11 +18,11 @@ use crate::collect_tool_search_app_infos;
 use crate::collect_tool_suggest_entries;
 use crate::create_apply_patch_freeform_tool;
 use crate::create_apply_patch_json_tool;
-use crate::create_assign_task_tool;
 use crate::create_close_agent_tool_v1;
 use crate::create_close_agent_tool_v2;
 use crate::create_code_mode_tool;
 use crate::create_exec_command_tool;
+use crate::create_followup_task_tool;
 use crate::create_image_generation_tool;
 use crate::create_js_repl_reset_tool;
 use crate::create_js_repl_tool;
@@ -358,7 +358,7 @@ pub fn build_tool_registry_plan(
                 config.code_mode_enabled,
             );
             plan.push_spec(
-                create_assign_task_tool(),
+                create_followup_task_tool(),
                 /*supports_parallel_tool_calls*/ false,
                 config.code_mode_enabled,
             );
@@ -379,7 +379,7 @@ pub fn build_tool_registry_plan(
             );
             plan.register_handler("spawn_agent", ToolHandlerKind::SpawnAgentV2);
             plan.register_handler("send_message", ToolHandlerKind::SendMessageV2);
-            plan.register_handler("assign_task", ToolHandlerKind::AssignTaskV2);
+            plan.register_handler("followup_task", ToolHandlerKind::FollowupTaskV2);
             plan.register_handler("wait_agent", ToolHandlerKind::WaitAgentV2);
             plan.register_handler("close_agent", ToolHandlerKind::CloseAgentV2);
             plan.register_handler("list_agents", ToolHandlerKind::ListAgentsV2);
diff --git a/codex-rs/tools/src/tool_registry_plan_tests.rs b/codex-rs/tools/src/tool_registry_plan_tests.rs
index c2c4a0aea..fd7ab1007 100644
--- a/codex-rs/tools/src/tool_registry_plan_tests.rs
+++ b/codex-rs/tools/src/tool_registry_plan_tests.rs
@@ -207,7 +207,7 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
         &[
             "spawn_agent",
             "send_message",
-            "assign_task",
+            "followup_task",
             "wait_agent",
             "close_agent",
             "list_agents",
@@ -269,9 +269,9 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
         Some(&vec!["target".to_string(), "message".to_string()])
     );
 
-    let assign_task = find_tool(&tools, "assign_task");
-    let ToolSpec::Function(ResponsesApiTool { parameters, .. }) = &assign_task.spec else {
-        panic!("assign_task should be a function tool");
+    let followup_task = find_tool(&tools, "followup_task");
+    let ToolSpec::Function(ResponsesApiTool { parameters, .. }) = &followup_task.spec else {
+        panic!("followup_task should be a function tool");
     };
     let JsonSchema::Object {
         properties,
@@ -279,7 +279,7 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
         ..
     } = parameters
     else {
-        panic!("assign_task should use object params");
+        panic!("followup_task should use object params");
     };
     assert!(properties.contains_key("target"));
     assert!(properties.contains_key("message"));
diff --git a/codex-rs/tools/src/tool_registry_plan_types.rs b/codex-rs/tools/src/tool_registry_plan_types.rs
index bdcb75acd..d15cf15d5 100644
--- a/codex-rs/tools/src/tool_registry_plan_types.rs
+++ b/codex-rs/tools/src/tool_registry_plan_types.rs
@@ -12,12 +12,12 @@ use std::collections::HashMap;
 pub enum ToolHandlerKind {
     AgentJobs,
     ApplyPatch,
-    AssignTaskV2,
     CloseAgentV1,
     CloseAgentV2,
     CodeModeExecute,
     CodeModeWait,
     DynamicTool,
+    FollowupTaskV2,
     JsRepl,
     JsReplReset,
     ListAgentsV2,