feat: add tasks tool with dependencies and cross-session persistence

cmd/root/flags.go

@@ -16,10 +16,13 @@ import (
 const (
 	flagModelsGateway = "models-gateway"
 	envModelsGateway  = "CAGENT_MODELS_GATEWAY"
+	flagTaskList      = "task-list"
+	envTaskListID     = "CAGENT_TASK_LIST_ID"
 )
 
 func addRuntimeConfigFlags(cmd *cobra.Command, runConfig *config.RuntimeConfig) {
 	addGatewayFlags(cmd, runConfig)
+	addTaskListFlags(cmd, runConfig)
 	cmd.PersistentFlags().StringSliceVar(&runConfig.EnvFiles, "env-from-file", nil, "Set environment variables from file")
 	cmd.PersistentFlags().BoolVar(&runConfig.GlobalCodeMode, "code-mode-tools", false, "Provide a single tool to call other tools via Javascript")
 	cmd.PersistentFlags().StringVar(&runConfig.WorkingDir, "working-dir", "", "Set the working directory for the session (applies to tools and relative paths)")
@@ -94,3 +97,22 @@ func addGatewayFlags(cmd *cobra.Command, runConfig *config.RuntimeConfig) {
 		return nil
 	}
 }
+
+func addTaskListFlags(cmd *cobra.Command, runConfig *config.RuntimeConfig) {
+	cmd.PersistentFlags().StringVar(&runConfig.TaskListID, flagTaskList, "", "Use a persistent task list with the given ID")
+
+	persistentPreRunE := cmd.PersistentPreRunE
+	cmd.PersistentPreRunE = func(c *cobra.Command, args []string) error {
+		// Precedence: CLI flag > environment variable
+		if runConfig.TaskListID != "" {
+			logFlagShadowing(os.Getenv(envTaskListID), envTaskListID, flagTaskList)
+		} else if taskListID := os.Getenv(envTaskListID); taskListID != "" {
+			runConfig.TaskListID = taskListID
+		}
+
+		if persistentPreRunE != nil {
+			return persistentPreRunE(c, args)
+		}
+		return nil
+	}
+}

cmd/root/flags_test.go

@@ -152,3 +152,53 @@ func TestCanonize(t *testing.T) {
 		})
 	}
 }
+
+func TestTaskListLogic(t *testing.T) {
+	tests := []struct {
+		name     string
+		env      string
+		args     []string
+		expected string
+	}{
+		{
+			name:     "empty_by_default",
+			expected: "",
+		},
+		{
+			name:     "from_env",
+			env:      "my-project",
+			expected: "my-project",
+		},
+		{
+			name:     "from_cli",
+			args:     []string{"--task-list", "cli-project"},
+			expected: "cli-project",
+		},
+		{
+			name:     "cli_overrides_env",
+			env:      "env-project",
+			args:     []string{"--task-list", "cli-project"},
+			expected: "cli-project",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv("CAGENT_TASK_LIST_ID", tt.env)
+
+			cmd := &cobra.Command{
+				RunE: func(*cobra.Command, []string) error {
+					return nil
+				},
+			}
+			runConfig := config.RuntimeConfig{}
+			addTaskListFlags(cmd, &runConfig)
+
+			cmd.SetArgs(tt.args)
+			err := cmd.Execute()
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, runConfig.TaskListID)
+		})
+	}
+}

e2e/testdata/shared_tasks.yaml

@@ -0,0 +1,36 @@
+version: "2"
+
+agents:
+  root:
+    model: openai/gpt-5-mini
+    description: Coordinator that delegates to specialized agents
+    instruction: |
+      You coordinate work using a shared task list.
+      Use transfer_task to delegate work to sub-agents.
+    sub_agents:
+      - backend
+      - frontend
+    toolsets:
+      - type: tasks
+        shared: true
+      - type: transfer_task
+
+  backend:
+    model: openai/gpt-5-mini
+    description: Backend developer
+    instruction: |
+      You handle backend tasks.
+      You share a task list with other agents.
+    toolsets:
+      - type: tasks
+        shared: true
+
+  frontend:
+    model: openai/gpt-5-mini
+    description: Frontend developer
+    instruction: |
+      You handle frontend tasks.
+      You share a task list with other agents.
+    toolsets:
+      - type: tasks
+        shared: true

e2e/testdata/tasks_dependencies.yaml

@@ -0,0 +1,16 @@
+version: "2"
+
+agents:
+  root:
+    model: openai/gpt-5-mini
+    description: Test agent for tasks with dependencies
+    instruction: |
+      You are a helpful assistant that uses tasks tools with dependencies.
+
+      When creating tasks:
+      - Use blocked_by to specify dependencies
+      - Use owner to assign tasks
+
+      Always use the tasks tools to track work.
+    toolsets:
+      - type: tasks

golang_developer.yaml

@@ -97,7 +97,7 @@ agents:
     toolsets:
       - type: filesystem
       - type: shell
-      - type: todo
+      - type: tasks
       - type: fetch
     sub_agents:
       - librarian

pkg/config/runtime.go

@@ -20,6 +20,7 @@ type Config struct {
 	ModelsGateway  string
 	GlobalCodeMode bool
 	WorkingDir     string
+	TaskListID     string // ID for persistent task list (from --task-list or CAGENT_TASK_LIST_ID)
 }
 
 func (runConfig *RuntimeConfig) Clone() *RuntimeConfig {

pkg/paths/paths.go

@@ -41,3 +41,8 @@ func GetHomeDir() string {
 	}
 	return filepath.Clean(homeDir)
 }
+
+// GetTasksDir returns the directory for storing task lists.
+func GetTasksDir() string {
+	return filepath.Join(GetDataDir(), "tasks")
+}

pkg/teamloader/registry.go

@@ -59,6 +59,7 @@ func NewDefaultToolsetRegistry() *ToolsetRegistry {
 	r := NewToolsetRegistry()
 	// Register all built-in toolset creators
 	r.Register("todo", createTodoTool)
+	r.Register("tasks", createTasksTool)
 	r.Register("memory", createMemoryTool)
 	r.Register("think", createThinkTool)
 	r.Register("shell", createShellTool)
@@ -80,6 +81,24 @@ func createTodoTool(_ context.Context, toolset latest.Toolset, _ string, _ *conf
 	return builtin.NewTodoTool(), nil
 }
 
+func createTasksTool(_ context.Context, toolset latest.Toolset, _ string, runConfig *config.RuntimeConfig) (tools.ToolSet, error) {
+	// Determine task list ID: CLI/env takes precedence
+	listID := runConfig.TaskListID
+
+	if toolset.Shared {
+		// Shared mode uses in-memory storage (no persistence)
+		return builtin.NewSharedTasksTool(), nil
+	}
+
+	if listID != "" {
+		// Use file-based persistence with the specified list ID
+		return builtin.NewTasksToolWithStore(builtin.NewFileTaskStore(listID)), nil
+	}
+
+	// Default: in-memory only (no persistence)
+	return builtin.NewTasksTool(), nil
+}
+
 func createMemoryTool(_ context.Context, toolset latest.Toolset, parentDir string, runConfig *config.RuntimeConfig) (tools.ToolSet, error) {
 	var memoryPath string
 	if filepath.IsAbs(toolset.Path) {