feat: drop agent ID from v2 (#17005)

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

@@ -1554,7 +1554,7 @@ async fn multi_agent_v2_interrupted_turn_does_not_notify_parent() {
 }
 
 #[tokio::test]
-async fn multi_agent_v2_spawn_includes_agent_id_key_when_named() {
+async fn multi_agent_v2_spawn_omits_agent_id_when_named() {
     let (mut session, mut turn) = make_session_and_context().await;
     let manager = thread_manager();
     let root = manager
@@ -1586,7 +1586,7 @@ async fn multi_agent_v2_spawn_includes_agent_id_key_when_named() {
     let result: serde_json::Value =
         serde_json::from_str(&content).expect("spawn_agent result should be json");
 
-    assert_eq!(result["agent_id"], serde_json::Value::Null);
+    assert!(result.get("agent_id").is_none());
     assert_eq!(result["task_name"], "/root/test_process");
     assert!(result.get("nickname").is_some());
     assert_eq!(success, Some(true));

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

@@ -209,7 +209,6 @@ impl ToolHandler for Handler {
         })?;
 
         Ok(SpawnAgentResult {
-            agent_id: None,
             task_name,
             nickname,
         })
@@ -269,7 +268,6 @@ impl SpawnAgentArgs {
 
 #[derive(Debug, Serialize)]
 pub(crate) struct SpawnAgentResult {
-    agent_id: Option<String>,
     task_name: String,
     nickname: Option<String>,
 }

codex-rs/tools/src/agent_tool.rs

@@ -375,10 +375,6 @@ fn spawn_agent_output_schema_v2() -> Value {
     json!({
         "type": "object",
         "properties": {
-            "agent_id": {
-                "type": ["string", "null"],
-                "description": "Legacy thread identifier for the spawned agent."
-            },
             "task_name": {
                 "type": "string",
                 "description": "Canonical task name for the spawned agent."
@@ -388,7 +384,7 @@ fn spawn_agent_output_schema_v2() -> Value {
                 "description": "User-facing nickname for the spawned agent when available."
             }
         },
-        "required": ["agent_id", "task_name", "nickname"],
+        "required": ["task_name", "nickname"],
         "additionalProperties": false
     })
 }

codex-rs/tools/src/agent_tool_tests.rs

@@ -73,7 +73,7 @@ fn spawn_agent_tool_v2_requires_task_name_and_lists_visible_models() {
     );
     assert_eq!(
         output_schema.expect("spawn_agent output schema")["required"],
-        json!(["agent_id", "task_name", "nickname"])
+        json!(["task_name", "nickname"])
     );
 }
 

codex-rs/tools/src/tool_registry_plan_tests.rs

@@ -243,10 +243,7 @@ fn test_build_specs_multi_agent_v2_uses_task_names_and_hides_resume() {
     let output_schema = output_schema
         .as_ref()
         .expect("spawn_agent should define output schema");
-    assert_eq!(
-        output_schema["required"],
-        json!(["agent_id", "task_name", "nickname"])
-    );
+    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 {