Keep request_user_input visible in subagents

codex-rs/core/src/agent/agent_resolver.rs

@@ -2,6 +2,8 @@ use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::function_tool::FunctionCallError;
 use codex_protocol::ThreadId;
+use codex_protocol::protocol::SessionSource;
+use codex_protocol::protocol::SubAgentSource;
 use std::sync::Arc;
 
 /// Resolves a single tool-facing agent target to a thread id.
@@ -14,6 +16,13 @@ pub(crate) async fn resolve_agent_target(
     if let Ok(thread_id) = ThreadId::from_string(target) {
         return Ok(thread_id);
     }
+    if matches!(target, "parent" | "root")
+        && let SessionSource::SubAgent(SubAgentSource::ThreadSpawn {
+            parent_thread_id, ..
+        }) = &turn.session_source
+    {
+        return Ok(*parent_thread_id);
+    }
 
     session
         .services

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

@@ -6,6 +6,7 @@ use crate::tools::handlers::parse_arguments;
 use crate::tools::registry::ToolHandler;
 use crate::tools::registry::ToolKind;
 use async_trait::async_trait;
+use codex_protocol::protocol::SessionSource;
 use codex_protocol::request_user_input::RequestUserInputArgs;
 use codex_tools::REQUEST_USER_INPUT_TOOL_NAME;
 use codex_tools::normalize_request_user_input_args;
@@ -41,6 +42,12 @@ impl ToolHandler for RequestUserInputHandler {
             }
         };
 
+        if matches!(turn.session_source, SessionSource::SubAgent(_)) {
+            return Err(FunctionCallError::RespondToModel(
+                "request_user_input can only be used by the root thread".to_string(),
+            ));
+        }
+
         let mode = session.collaboration_mode().await.mode;
         if let Some(message) =
             request_user_input_unavailable_message(mode, self.default_mode_request_user_input)

codex-rs/tools/src/tool_config.rs

@@ -141,7 +141,7 @@ impl ToolsConfig {
         let include_collab_tools = features.enabled(Feature::Collab);
         let include_multi_agent_v2 = features.enabled(Feature::MultiAgentV2);
         let include_agent_jobs = features.enabled(Feature::SpawnCsv);
-        let include_request_user_input = !matches!(session_source, SessionSource::SubAgent(_));
+        let include_request_user_input = true;
         let include_default_mode_request_user_input =
             include_request_user_input && features.enabled(Feature::DefaultModeRequestUserInput);
         let include_search_tool =

codex-rs/tools/src/tool_config_tests.rs

@@ -131,7 +131,7 @@ fn shell_zsh_fork_prefers_shell_command_over_unified_exec() {
 }
 
 #[test]
-fn subagents_disable_request_user_input_and_agent_jobs_workers_opt_in_by_label() {
+fn subagents_keep_request_user_input_schema_and_agent_jobs_workers_opt_in_by_label() {
     let model_info = model_info();
     let mut features = Features::with_defaults();
     features.enable(Feature::SpawnCsv);
@@ -149,7 +149,7 @@ fn subagents_disable_request_user_input_and_agent_jobs_workers_opt_in_by_label()
         windows_sandbox_level: WindowsSandboxLevel::Disabled,
     });
 
-    assert!(!tools_config.request_user_input);
+    assert!(tools_config.request_user_input);
     assert!(!tools_config.default_mode_request_user_input);
     assert!(tools_config.agent_jobs_tools);
     assert!(tools_config.agent_jobs_worker_tools);