Add todo mode and replace the plan with TODO.md

internal/agents/manager_test.go

@@ -2,6 +2,7 @@ package agents_test
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -873,6 +874,68 @@ func TestCreateTaskTool(t *testing.T) {
 	}
 }
 
+func TestStartTodo(t *testing.T) {
+	t.Parallel()
+	e := newEnv(t)
+	m := e.manager()
+
+	writeTestFile(t, filepath.Join(e.repo, "TODO.md"), "# Todo\n\n- Create hello.txt\n  It holds the single line `hi`.\n- Leave this one alone\n")
+	gitOut(t, e.repo, "add", "TODO.md")
+	gitOut(t, e.repo, "commit", "--quiet", "--message", "add todo")
+
+	_, err := m.StartTodo(e.ctx, e.project, e.user, "No such item", testModel)
+	if !errors.Is(err, store.ErrNotFound) {
+		t.Fatalf("start unknown item: %v", err)
+	}
+
+	task, err := m.StartTodo(e.ctx, e.project, e.user, "Create hello.txt", testModel)
+	if err != nil {
+		t.Fatalf("start todo: %v", err)
+	}
+	if task.TodoItem == nil || *task.TodoItem != "Create hello.txt" || task.Title != "Create hello.txt" {
+		t.Fatalf("todo task %+v", task)
+	}
+
+	_, err = m.StartTodo(e.ctx, e.project, e.user, "Create hello.txt", testModel)
+	if !errors.Is(err, agents.ErrConflict) {
+		t.Fatalf("second start of the same item: %v", err)
+	}
+
+	events := e.waitFor("todo turn end", func(ev api.Event) bool {
+		return ev.Kind == "turn.ended" && ev.TaskId != nil && *ev.TaskId == task.Id
+	})
+	for _, ev := range events {
+		if ev.Kind == "user.message" && ev.TaskId != nil && *ev.TaskId == task.Id {
+			text, _ := ev.Payload["text"].(string)
+			if !strings.Contains(text, "- Create hello.txt\n  It holds the single line `hi`.") || !strings.Contains(text, "remove this item from TODO.md") {
+				t.Fatalf("first prompt %q", text)
+			}
+		}
+	}
+
+	stored, err := e.store.GetTask(e.ctx, task.Id)
+	if err != nil || stored.TodoItem == nil || *stored.TodoItem != "Create hello.txt" {
+		t.Fatalf("stored task %+v %v", stored, err)
+	}
+
+	todoAfter, err := os.ReadFile(filepath.Join(task.WorktreePath, "TODO.md"))
+	if err != nil {
+		t.Fatalf("read worktree TODO.md: %v", err)
+	}
+	t.Logf("TODO.md after the turn:\n%s", todoAfter)
+	if strings.Contains(string(todoAfter), "Create hello.txt") || !strings.Contains(string(todoAfter), "Leave this one alone") {
+		t.Fatalf("agent didn't remove exactly its item from TODO.md")
+	}
+}
+
+func writeTestFile(t *testing.T, path, content string) {
+	t.Helper()
+	err := os.WriteFile(path, []byte(content), 0o644)
+	if err != nil {
+		t.Fatalf("write %s: %v", path, err)
+	}
+}
+
 func TestQuestionReachesInbox(t *testing.T) {
 	t.Parallel()
 	e := newEnv(t)