Agent startup holds the manager's global lock

internal/agents/queue.go

@@ -6,14 +6,42 @@ import (
 	"fmt"
 	"log/slog"
 	"strings"
+	"sync"
 
 	"g.fc.run/misc/byre/internal/api"
 	"g.fc.run/misc/byre/internal/store"
 )
 
-func (m *Manager) Message(ctx context.Context, sessionID, actor, text, model string, images ...string) (api.AgentSession, error) {
+type sessionLock struct {
+	mu   sync.Mutex
+	refs int
+}
+
+func (m *Manager) lockDelivery(sessionID string) func() {
 	m.deliverMu.Lock()
-	defer m.deliverMu.Unlock()
+	sl := m.deliverLocks[sessionID]
+	if sl == nil {
+		sl = &sessionLock{}
+		m.deliverLocks[sessionID] = sl
+	}
+	sl.refs++
+	m.deliverMu.Unlock()
+
+	sl.mu.Lock()
+	return func() {
+		sl.mu.Unlock()
+		m.deliverMu.Lock()
+		sl.refs--
+		if sl.refs == 0 {
+			delete(m.deliverLocks, sessionID)
+		}
+		m.deliverMu.Unlock()
+	}
+}
+
+func (m *Manager) Message(ctx context.Context, sessionID, actor, text, model string, images ...string) (api.AgentSession, error) {
+	unlock := m.lockDelivery(sessionID)
+	defer unlock()
 
 	sess, err := m.store.GetSession(ctx, sessionID)
 	if err != nil {
@@ -77,9 +105,9 @@ func (m *Manager) deliverAllQueued(ctx context.Context) {
 		if sess.Role != api.Implementer {
 			continue
 		}
-		m.deliverMu.Lock()
+		unlock := m.lockDelivery(sess.Id)
 		_, err = m.deliverQueued(ctx, sess)
-		m.deliverMu.Unlock()
+		unlock()
 		if err != nil {
 			slog.Error("deliver queued message", "session", sess.Id, "err", err)
 		}