drop SubagentRunner::ready

crates/goose-agent/src/subagent.rs

@@ -34,8 +34,6 @@ pub trait SubagentRunner<S>: MaybeSend + MaybeSync {
         conversation: &Conversation,
     ) -> Vec<String>;
 
-    fn ready(&self, parent_session: &S, conversation: &Conversation) -> Result<bool>;
-
     async fn start(
         &self,
         parent_session: &S,
@@ -220,10 +218,7 @@ where
             self.runner
                 .started_subagent_session_ids(session, conversation),
         );
-        if pending.is_empty() || !self.runner.ready(session, conversation)? {
-            return not_applicable();
-        }
-        let remaining = pending.len() - 1;
+        let remaining = pending.len().saturating_sub(1);
 
         let mut running = self.running.lock().await;
         for subagent_session_id in &pending {

crates/goose-agent/tests/subagent.rs

@@ -2,7 +2,6 @@ use std::collections::HashMap;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 
-use anyhow::Result;
 use async_trait::async_trait;
 use futures::future;
 use futures::FutureExt;
@@ -28,7 +27,6 @@ struct FakeRunner {
     started: Mutex<Vec<String>>,
     events: Mutex<Vec<String>>,
     started_subagent_session_ids: Vec<String>,
-    blocked: bool,
     stall_next_hook: AtomicBool,
 }
 
@@ -68,10 +66,6 @@ impl SubagentRunner<Parent> for FakeRunner {
         self.started_subagent_session_ids.clone()
     }
 
-    fn ready(&self, _parent_session: &Parent, _conversation: &Conversation) -> Result<bool> {
-        Ok(!self.blocked)
-    }
-
     async fn start(
         &self,
         _parent_session: &Parent,
@@ -192,21 +186,6 @@ async fn stop(
     )
 }
 
-#[tokio::test]
-async fn nothing_starts_until_the_runner_is_ready() {
-    let runner = Arc::new(FakeRunner {
-        blocked: true,
-        ..fake(&["a"])
-    });
-    runner.finished("a", SubagentOutcome::Completed("done".into()));
-
-    let delivered = run_once(&operation(&runner), &[kickoff()]).await;
-
-    assert!(delivered.is_empty());
-    assert!(runner.started().is_empty());
-    assert!(runner.events().is_empty());
-}
-
 #[tokio::test]
 async fn a_finished_subagent_is_delivered_without_running() {
     let runner = Arc::new(fake(&["a"]));

crates/goose/src/agents/state_machine/ops_foreground_subagent.rs

@@ -1,4 +1,3 @@
-use anyhow::Result;
 use async_trait::async_trait;
 use futures::future::{self, BoxFuture};
 use goose_agent::subagent::{SubagentOutcome, SubagentRunner};
@@ -86,7 +85,9 @@ impl SubagentRunner<Session> for ForegroundSubagentRunner {
         parent_session: &Session,
         conversation: &Conversation,
     ) -> Vec<String> {
-        if parent_session.session_type == SessionType::SubAgent {
+        let all_tool_calls_answered = messages_since_kickoff(conversation)
+            .is_ok_and(|messages| !awaits_tool_responses(messages));
+        if parent_session.session_type == SessionType::SubAgent || !all_tool_calls_answered {
             return Vec::new();
         }
         conversation
@@ -97,12 +98,6 @@ impl SubagentRunner<Session> for ForegroundSubagentRunner {
             .collect()
     }
 
-    fn ready(&self, _parent_session: &Session, conversation: &Conversation) -> Result<bool> {
-        Ok(!awaits_tool_responses(messages_since_kickoff(
-            conversation,
-        )?))
-    }
-
     async fn start(
         &self,
         parent_session: &Session,
@@ -154,6 +149,7 @@ impl SubagentRunner<Session> for ForegroundSubagentRunner {
 mod tests {
     use std::sync::Arc;
 
+    use anyhow::Result;
     use goose_agent::events::AgentEvent;
     use goose_agent::subagent::ForegroundSubagentOperation;
     use rmcp::model::{CallToolRequestParams, CallToolResult, ContentBlock, MetaObject};
@@ -308,6 +304,7 @@ mod tests {
         let mut failed_delegate = delegate_result("failed", true);
         failed_delegate.is_error = Some(true);
         let conversation = Conversation::new_unvalidated(vec![
+            Message::user().with_text("delegate"),
             Message::user()
                 .with_tool_response("a", Ok(delegate_result("first", true)))
                 .with_tool_response("b", Ok(delegate_result("background", false)))
@@ -351,13 +348,18 @@ mod tests {
             requests,
             delegate_message("s1"),
         ];
-        assert!(!runner.ready(&parent, &Conversation::new_unvalidated(messages.clone()))?);
+        assert!(runner
+            .started_subagent_session_ids(&parent, &Conversation::new_unvalidated(messages.clone()))
+            .is_empty());
 
         messages.push(Message::user().with_tool_response(
             "other-call",
             Ok(CallToolResult::success(vec![ContentBlock::text("done")])),
         ));
-        assert!(runner.ready(&parent, &Conversation::new_unvalidated(messages))?);
+        assert_eq!(
+            runner.started_subagent_session_ids(&parent, &Conversation::new_unvalidated(messages)),
+            ["s1"]
+        );
         Ok(())
     }