fix: reconnect stale Lingma IPC sessions

internal/service/service.go

@@ -229,7 +229,7 @@ func (s *Service) ListModels(ctx context.Context) ([]Model, error) {
 }
 
 func (s *Service) Generate(ctx context.Context, req ChatRequest) (*ChatResult, error) {
-	return s.generateLocked(ctx, req, nil)
+	return s.generateWithReconnect(ctx, req, nil)
 }
 
 func (s *Service) GenerateStream(ctx context.Context, req ChatRequest) (<-chan StreamEvent, <-chan StreamResult, error) {
@@ -237,7 +237,7 @@ func (s *Service) GenerateStream(ctx context.Context, req ChatRequest) (<-chan S
 	done := make(chan StreamResult, 1)
 
 	go func() {
-		result, err := s.generateLocked(ctx, req, func(delta string) {
+		result, err := s.generateWithReconnect(ctx, req, func(delta string) {
 			if delta == "" {
 				return
 			}
@@ -255,6 +255,20 @@ func (s *Service) GenerateStream(ctx context.Context, req ChatRequest) (<-chan S
 	return events, done, nil
 }
 
+func (s *Service) generateWithReconnect(
+	ctx context.Context,
+	req ChatRequest,
+	onDelta func(string),
+) (*ChatResult, error) {
+	result, err := s.generateLocked(ctx, req, onDelta)
+	if err == nil || !isRecoverableIPCError(err) {
+		return result, err
+	}
+
+	s.resetConnection()
+	return s.generateLocked(ctx, req, onDelta)
+}
+
 func (s *Service) generateLocked(
 	ctx context.Context,
 	req ChatRequest,
@@ -388,6 +402,29 @@ func shouldRetryTooling(choice toolemulation.ToolChoice, text string) bool {
 	return toolemulation.LooksLikeRefusal(text) || toolemulation.LooksLikeMissedToolUse(text)
 }
 
+func isRecoverableIPCError(err error) bool {
+	if err == nil {
+		return false
+	}
+	text := strings.ToLower(err.Error())
+	needles := []string{
+		"use of closed network connection",
+		"broken pipe",
+		"connection reset by peer",
+		"connection refused",
+		"websocket: close",
+		"unexpected eof",
+		"io: read/write on closed pipe",
+		"lingma ipc notification stream closed",
+	}
+	for _, needle := range needles {
+		if strings.Contains(text, needle) {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *Service) buildChatResult(
 	req ChatRequest,
 	sessionID string,
@@ -467,6 +504,12 @@ func (s *Service) closeClientLocked() error {
 	return client.Close()
 }
 
+func (s *Service) resetConnection() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	_ = s.closeClientLocked()
+}
+
 func (s *Service) resolveSession(ctx context.Context, client *lingmaipc.Client, mode SessionMode) (string, error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()

internal/service/service_test.go

@@ -0,0 +1,25 @@
+package service
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestIsRecoverableIPCError(t *testing.T) {
+	cases := []error{
+		errors.New("write websocket frame: write tcp 127.0.0.1:64954->127.0.0.1:36510: use of closed network connection"),
+		errors.New("broken pipe"),
+		errors.New("Lingma IPC notification stream closed"),
+	}
+	for _, err := range cases {
+		if !isRecoverableIPCError(err) {
+			t.Fatalf("expected recoverable error: %v", err)
+		}
+	}
+}
+
+func TestIsRecoverableIPCErrorIgnoresModelErrors(t *testing.T) {
+	if isRecoverableIPCError(errors.New("timed out while waiting for Lingma IPC to finish responding")) {
+		t.Fatal("timeout should not be treated as an immediate reconnect retry")
+	}
+}