chore: send_message and followup_task do not return anything (#17008)

codex-rs/core/src/tools/handlers/multi_agents_tests.rs

@@ -757,7 +757,7 @@ async fn multi_agent_v2_followup_task_rejects_root_target_from_child() {
         agent_role: None,
     });
 
-    let err = FollowupTaskHandlerV2
+    let Err(err) = FollowupTaskHandlerV2
         .handle(invocation(
             Arc::new(session),
             Arc::new(turn),
@@ -769,7 +769,9 @@ async fn multi_agent_v2_followup_task_rejects_root_target_from_child() {
             })),
         ))
         .await
-        .expect_err("followup_task should reject the root target");
+    else {
+        panic!("followup_task should reject the root target");
+    };
 
     assert_eq!(
         err,

codex-rs/core/src/tools/handlers/multi_agents_v2/followup_task.rs

@@ -1,13 +1,13 @@
 use super::message_tool::FollowupTaskArgs;
 use super::message_tool::MessageDeliveryMode;
-use super::message_tool::MessageToolResult;
 use super::message_tool::handle_message_string_tool;
 use super::*;
+use crate::tools::context::FunctionToolOutput;
 
 pub(crate) struct Handler;
 
 impl ToolHandler for Handler {
-    type Output = MessageToolResult;
+    type Output = FunctionToolOutput;
 
     fn kind(&self) -> ToolKind {
         ToolKind::Function

codex-rs/core/src/tools/handlers/multi_agents_v2/message_tool.rs

@@ -4,6 +4,7 @@
 //! resulting `InterAgentCommunication` should wake the target immediately.
 
 use super::*;
+use crate::tools::context::FunctionToolOutput;
 use codex_protocol::protocol::InterAgentCommunication;
 
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -46,30 +47,6 @@ pub(crate) struct FollowupTaskArgs {
     pub(crate) interrupt: bool,
 }
 
-#[derive(Debug, Serialize)]
-/// Tool result shared by the MultiAgentV2 message-delivery tools.
-pub(crate) struct MessageToolResult {
-    submission_id: String,
-}
-
-impl ToolOutput for MessageToolResult {
-    fn log_preview(&self) -> String {
-        tool_output_json_text(self, "multi_agent_message")
-    }
-
-    fn success_for_logging(&self) -> bool {
-        true
-    }
-
-    fn to_response_item(&self, call_id: &str, payload: &ToolPayload) -> ResponseInputItem {
-        tool_output_response_item(call_id, payload, self, Some(true), "multi_agent_message")
-    }
-
-    fn code_mode_result(&self, _payload: &ToolPayload) -> JsonValue {
-        tool_output_code_mode_result(self, "multi_agent_message")
-    }
-}
-
 fn message_content(message: String) -> Result<String, FunctionCallError> {
     if message.trim().is_empty() {
         return Err(FunctionCallError::RespondToModel(
@@ -86,7 +63,7 @@ pub(crate) async fn handle_message_string_tool(
     target: String,
     message: String,
     interrupt: bool,
-) -> Result<MessageToolResult, FunctionCallError> {
+) -> Result<FunctionToolOutput, FunctionCallError> {
     handle_message_submission(
         invocation,
         mode,
@@ -103,15 +80,13 @@ async fn handle_message_submission(
     target: String,
     prompt: String,
     interrupt: bool,
-) -> Result<MessageToolResult, FunctionCallError> {
+) -> Result<FunctionToolOutput, FunctionCallError> {
     let ToolInvocation {
         session,
         turn,
-        payload,
         call_id,
         ..
     } = invocation;
-    let _ = payload;
     let receiver_thread_id = resolve_agent_target(&session, &turn, &target).await?;
     let receiver_agent = session
         .services
@@ -186,7 +161,7 @@ async fn handle_message_submission(
             .into(),
         )
         .await;
-    let submission_id = result?;
+    result?;
 
-    Ok(MessageToolResult { submission_id })
+    Ok(FunctionToolOutput::from_text(String::new(), Some(true)))
 }

codex-rs/core/src/tools/handlers/multi_agents_v2/send_message.rs

@@ -1,13 +1,13 @@
 use super::message_tool::MessageDeliveryMode;
-use super::message_tool::MessageToolResult;
 use super::message_tool::SendMessageArgs;
 use super::message_tool::handle_message_string_tool;
 use super::*;
+use crate::tools::context::FunctionToolOutput;
 
 pub(crate) struct Handler;
 
 impl ToolHandler for Handler {
-    type Output = MessageToolResult;
+    type Output = FunctionToolOutput;
 
     fn kind(&self) -> ToolKind {
         ToolKind::Function

codex-rs/tools/src/agent_tool.rs

@@ -155,7 +155,7 @@ pub fn create_send_message_tool() -> ToolSpec {
             required: Some(vec!["target".to_string(), "message".to_string()]),
             additional_properties: Some(false.into()),
         },
-        output_schema: Some(send_input_output_schema()),
+        output_schema: None,
     })
 }
 
@@ -197,7 +197,7 @@ pub fn create_followup_task_tool() -> ToolSpec {
             required: Some(vec!["target".to_string(), "message".to_string()]),
             additional_properties: Some(false.into()),
         },
-        output_schema: Some(send_input_output_schema()),
+        output_schema: None,
     })
 }
 

codex-rs/tools/src/agent_tool_tests.rs

@@ -97,7 +97,7 @@ fn spawn_agent_tool_v1_keeps_legacy_fork_context_field() {
 }
 
 #[test]
-fn send_message_tool_requires_message_and_uses_submission_output() {
+fn send_message_tool_requires_message_and_has_no_output_schema() {
     let ToolSpec::Function(ResponsesApiTool {
         parameters,
         output_schema,
@@ -122,14 +122,11 @@ fn send_message_tool_requires_message_and_uses_submission_output() {
         required,
         Some(vec!["target".to_string(), "message".to_string()])
     );
-    assert_eq!(
-        output_schema.expect("send_message output schema")["required"],
-        json!(["submission_id"])
-    );
+    assert_eq!(output_schema, None);
 }
 
 #[test]
-fn followup_task_tool_requires_message_and_uses_submission_output() {
+fn followup_task_tool_requires_message_and_has_no_output_schema() {
     let ToolSpec::Function(ResponsesApiTool {
         parameters,
         output_schema,
@@ -154,10 +151,7 @@ fn followup_task_tool_requires_message_and_uses_submission_output() {
         required,
         Some(vec!["target".to_string(), "message".to_string()])
     );
-    assert_eq!(
-        output_schema.expect("followup_task output schema")["required"],
-        json!(["submission_id"])
-    );
+    assert_eq!(output_schema, None);
 }
 
 #[test]

codex-rs/tools/src/tool_registry_plan_tests.rs

@@ -246,9 +246,15 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
     assert_eq!(output_schema["required"], json!(["task_name", "nickname"]));
 
     let send_message = find_tool(&tools, "send_message");
-    let ToolSpec::Function(ResponsesApiTool { parameters, .. }) = &send_message.spec else {
+    let ToolSpec::Function(ResponsesApiTool {
+        parameters,
+        output_schema,
+        ..
+    }) = &send_message.spec
+    else {
         panic!("send_message should be a function tool");
     };
+    assert_eq!(output_schema, &None);
     let JsonSchema::Object {
         properties,
         required,
@@ -267,9 +273,15 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
     );
 
     let followup_task = find_tool(&tools, "followup_task");
-    let ToolSpec::Function(ResponsesApiTool { parameters, .. }) = &followup_task.spec else {
+    let ToolSpec::Function(ResponsesApiTool {
+        parameters,
+        output_schema,
+        ..
+    }) = &followup_task.spec
+    else {
         panic!("followup_task should be a function tool");
     };
+    assert_eq!(output_schema, &None);
     let JsonSchema::Object {
         properties,
         required,