Fix parallel sessions killing each other via shared queue file

cmd/root.go

@@ -56,10 +56,10 @@ func (p *progress) Clear() {
 var Version = "dev"
 
 func Execute() error {
-	// Clear stale next action on every invocation (except check-queue which reads it)
+	// Clear stale queue files on every invocation (except check-queue which reads them)
 	if len(os.Args) < 2 || os.Args[1] != "check-queue" {
 		if root, err := mob.FindRepoRoot(); err == nil {
-			mob.ClearQueue(root)
+			mob.ClearAllQueues(root)
 		}
 	}
 
@@ -741,11 +741,16 @@ func cmdCheckNext(_ []string) error {
 		return nil // not in a repo, nothing to do
 	}
 
-	next, err := mob.ReadQueuedAction(root)
+	mobName := mob.CurrentMobName()
+	if mobName == "" {
+		return nil // not in a mob, nothing to do
+	}
+
+	next, err := mob.ReadQueuedAction(root, mobName)
 	if err != nil || next == nil {
 		return nil // no queued action
 	}
-	mob.ClearQueue(root)
+	mob.ClearQueue(root, mobName)
 
 	return executeNextAction(root, next)
 }
@@ -891,7 +896,11 @@ func cmdWriteNext(args []string) error {
 		}
 	}
 
-	return mob.WriteQueuedAction(root, q)
+	currentMob := mob.CurrentMobName()
+	if currentMob == "" {
+		return fmt.Errorf("codemob queue must be run from inside a mob")
+	}
+	return mob.WriteQueuedAction(root, currentMob, q)
 }
 
 // launchAgent spawns the agent as a child process and implements the trampoline loop.
@@ -911,12 +920,13 @@ func launchAgent(root, agent, workdir string, resume bool) error {
 		mobStatus(fmt.Sprintf("Session ended - mob '%s'", filepath.Base(workdir)))
 
 		// Always check for queued action, regardless of how the agent exited
-		next, err := mob.ReadQueuedAction(root)
+		mobName := filepath.Base(workdir)
+		next, err := mob.ReadQueuedAction(root, mobName)
 		if err != nil || next == nil {
 			writeLastMob(workdir)
 			return nil // normal exit
 		}
-		mob.ClearQueue(root)
+		mob.ClearQueue(root, mobName)
 
 		newWorkdir, newAgent, newResume, err := resolveNextAction(root, next)
 		if err != nil {
@@ -1070,9 +1080,10 @@ func spawnAgent(root, binPath string, args []string, workdir string) error {
 		}
 	}()
 
-	// Watch for queue.json - auto-terminate agent when a queued action appears
+	// Watch for per-mob queue file - auto-terminate agent when a queued action appears
 	if root != "" && filepath.IsAbs(root) {
-		queuePath := mob.QueueFilePath(root)
+		mobName := filepath.Base(workdir)
+		queuePath := mob.QueueFilePath(root, mobName)
 		go func() {
 			ticker := time.NewTicker(500 * time.Millisecond)
 			defer ticker.Stop()

internal/mob/next.go

@@ -14,7 +14,7 @@ var ValidQueueActions = map[string]bool{
 	"change-agent": true,
 }
 
-const queueFile = ".codemob/queue.json"
+const queuesDir = ".codemob/queues"
 
 // QueuedAction represents a pending action to execute after an agent exits.
 type QueuedAction struct {
@@ -25,17 +25,21 @@ type QueuedAction struct {
 }
 
 // WriteQueuedAction writes an action for the trampoline to pick up.
-func WriteQueuedAction(repoRoot string, action QueuedAction) error {
+func WriteQueuedAction(repoRoot, mobName string, action QueuedAction) error {
 	data, err := json.MarshalIndent(action, "", "  ")
 	if err != nil {
 		return err
 	}
-	return os.WriteFile(filepath.Join(repoRoot, queueFile), append(data, '\n'), 0644)
+	path := QueueFilePath(repoRoot, mobName)
+	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+		return err
+	}
+	return os.WriteFile(path, append(data, '\n'), 0644)
 }
 
 // ReadQueuedAction reads and returns the pending action, if any.
-func ReadQueuedAction(repoRoot string) (*QueuedAction, error) {
-	data, err := os.ReadFile(filepath.Join(repoRoot, queueFile))
+func ReadQueuedAction(repoRoot, mobName string) (*QueuedAction, error) {
+	data, err := os.ReadFile(QueueFilePath(repoRoot, mobName))
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, nil // no file = no action
@@ -52,12 +56,17 @@ func ReadQueuedAction(repoRoot string) (*QueuedAction, error) {
 	return &action, nil
 }
 
-// QueueFilePath returns the absolute path to the queue file.
-func QueueFilePath(repoRoot string) string {
-	return filepath.Join(repoRoot, queueFile)
+// QueueFilePath returns the absolute path to the queue file for a given mob.
+func QueueFilePath(repoRoot, mobName string) string {
+	return filepath.Join(repoRoot, queuesDir, mobName+".json")
+}
+
+// ClearQueue removes the queued action file for a given mob.
+func ClearQueue(repoRoot, mobName string) {
+	os.Remove(QueueFilePath(repoRoot, mobName))
 }
 
-// ClearQueue removes the queued action file.
-func ClearQueue(repoRoot string) {
-	os.Remove(filepath.Join(repoRoot, queueFile))
+// ClearAllQueues removes all queued action files.
+func ClearAllQueues(repoRoot string) {
+	os.RemoveAll(filepath.Join(repoRoot, queuesDir))
 }