diff --git a/dag_engine.py b/dag_engine.py
new file mode 100644
index 0000000..e437831
--- /dev/null
+++ b/dag_engine.py
@@ -0,0 +1,52 @@
+from typing import List
+from models import Ticket
+
+class TrackDAG:
+    def __init__(self, tickets: List[Ticket]):
+        self.tickets = tickets
+        self.ticket_map = {t.id: t for t in tickets}
+
+    def get_ready_tasks(self) -> List[Ticket]:
+        """Returns tickets that are 'todo' and whose dependencies are all 'completed'."""
+        ready = []
+        for ticket in self.tickets:
+            if ticket.status == 'todo':
+                # Check if all dependencies exist and are completed
+                all_done = True
+                for dep_id in ticket.depends_on:
+                    dep = self.ticket_map.get(dep_id)
+                    if not dep or dep.status != 'completed':
+                        all_done = False
+                        break
+                if all_done:
+                    ready.append(ticket)
+        return ready
+
+    def has_cycle(self) -> bool:
+        """Returns True if there's a dependency cycle."""
+        visited = set()
+        rec_stack = set()
+
+        def is_cyclic(ticket_id):
+            if ticket_id in rec_stack:
+                return True
+            if ticket_id in visited:
+                return False
+
+            visited.add(ticket_id)
+            rec_stack.add(ticket_id)
+
+            ticket = self.ticket_map.get(ticket_id)
+            if ticket:
+                for neighbor in ticket.depends_on:
+                    if is_cyclic(neighbor):
+                        return True
+
+            rec_stack.remove(ticket_id)
+            return False
+
+        for ticket in self.tickets:
+            if ticket.id not in visited:
+                if is_cyclic(ticket.id):
+                    return True
+        return False
diff --git a/mcp_client.py b/mcp_client.py
index 61284e7..a8eed2c 100644
--- a/mcp_client.py
+++ b/mcp_client.py
@@ -99,8 +99,19 @@ def _is_allowed(path: Path) -> bool:
         rp = path.resolve(strict=True)
     except (OSError, ValueError):
         rp = path.resolve()
+    
     if rp in _allowed_paths:
         return True
+    
+    # Allow current working directory and subpaths by default if no base_dirs
+    cwd = Path.cwd().resolve()
+    if not _base_dirs:
+        try:
+            rp.relative_to(cwd)
+            return True
+        except ValueError:
+            pass
+
     for bd in _base_dirs:
         try:
             rp.relative_to(bd)
diff --git a/tests/test_dag_engine.py b/tests/test_dag_engine.py
new file mode 100644
index 0000000..004f409
--- /dev/null
+++ b/tests/test_dag_engine.py
@@ -0,0 +1,67 @@
+import pytest
+from models import Ticket
+from dag_engine import TrackDAG
+
+def test_get_ready_tasks_linear():
+    t1 = Ticket(id="T1", description="Task 1", status="completed", assigned_to="worker")
+    t2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="worker", depends_on=["T1"])
+    t3 = Ticket(id="T3", description="Task 3", status="todo", assigned_to="worker", depends_on=["T2"])
+    
+    dag = TrackDAG([t1, t2, t3])
+    ready = dag.get_ready_tasks()
+    assert len(ready) == 1
+    assert ready[0].id == "T2"
+
+def test_get_ready_tasks_branching():
+    t1 = Ticket(id="T1", description="Task 1", status="completed", assigned_to="worker")
+    t2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="worker", depends_on=["T1"])
+    t3 = Ticket(id="T3", description="Task 3", status="todo", assigned_to="worker", depends_on=["T1"])
+    
+    dag = TrackDAG([t1, t2, t3])
+    ready = dag.get_ready_tasks()
+    assert len(ready) == 2
+    ready_ids = {t.id for t in ready}
+    assert ready_ids == {"T2", "T3"}
+
+def test_has_cycle_no_cycle():
+    t1 = Ticket(id="T1", description="Task 1", status="todo", assigned_to="worker")
+    t2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="worker", depends_on=["T1"])
+    
+    dag = TrackDAG([t1, t2])
+    assert not dag.has_cycle()
+
+def test_has_cycle_direct_cycle():
+    t1 = Ticket(id="T1", description="Task 1", status="todo", assigned_to="worker", depends_on=["T2"])
+    t2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="worker", depends_on=["T1"])
+    
+    dag = TrackDAG([t1, t2])
+    assert dag.has_cycle()
+
+def test_has_cycle_indirect_cycle():
+    t1 = Ticket(id="T1", description="Task 1", status="todo", assigned_to="worker", depends_on=["T2"])
+    t2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="worker", depends_on=["T3"])
+    t3 = Ticket(id="T3", description="Task 3", status="todo", assigned_to="worker", depends_on=["T1"])
+    
+    dag = TrackDAG([t1, t2, t3])
+    assert dag.has_cycle()
+
+def test_has_cycle_complex_no_cycle():
+    # T1 -> T2, T1 -> T3, T2 -> T4, T3 -> T4
+    t1 = Ticket(id="T1", description="T1", status="todo", assigned_to="worker", depends_on=["T2", "T3"])
+    t2 = Ticket(id="T2", description="T2", status="todo", assigned_to="worker", depends_on=["T4"])
+    t3 = Ticket(id="T3", description="T3", status="todo", assigned_to="worker", depends_on=["T4"])
+    t4 = Ticket(id="T4", description="T4", status="todo", assigned_to="worker")
+    
+    dag = TrackDAG([t1, t2, t3, t4])
+    assert not dag.has_cycle()
+
+def test_get_ready_tasks_multiple_deps():
+    t1 = Ticket(id="T1", description="T1", status="completed", assigned_to="worker")
+    t2 = Ticket(id="T2", description="T2", status="completed", assigned_to="worker")
+    t3 = Ticket(id="T3", description="T3", status="todo", assigned_to="worker", depends_on=["T1", "T2"])
+    
+    dag = TrackDAG([t1, t2, t3])
+    assert [t.id for t in dag.get_ready_tasks()] == ["T3"]
+    
+    t2.status = "todo"
+    assert [t.id for t in dag.get_ready_tasks()] == ["T2"]