diff --git a/pantograph/gen_tactic.py b/pantograph/gen_tactic.py
index 24442ac..62ba918 100644
--- a/pantograph/gen_tactic.py
+++ b/pantograph/gen_tactic.py
@@ -1,4 +1,4 @@
-from pantograph.server import Server, ServerError
+from pantograph.server import Server, ServerError, TacticFailure
 from pantograph.expr import Variable, Goal, TacticCalc
 import  unittest
 import sglang as sgl
@@ -105,19 +105,24 @@ def select_tactic(s, server, state, goal_id, feedback_turns = 5):
             tactic = extract_code_from_llm_output(tmp["tactic"])
         s += sgl.assistant("```"+tactic+"```")
         success, new_state = apply_tactic(server, state, goal_id, tactic)
+        print("===execute===")
+        print(success, new_state )
         if not success:
             with s.user():
                 s += "This answer got Lean compile error:\n" + str(new_state) + "\n"
                 s += "Please try again by taking the Lean compiler feedback."
             
         else:
-            return new_state
+            return tactic, new_state
+    return None, None
 
 def apply_tactic(server, state, goal_id, tactic):
     try:
         new_state = server.goal_tactic(state, goal_id=goal_id, tactic=tactic)
     except ServerError as e:
         return False, e
+    except TacticFailure as e:
+        return False, e
     return True, new_state
     
 def extract_code_from_llm_output(reply):
diff --git a/pantograph/search.py b/pantograph/search.py
index 6a3d192..c48c6e4 100644
--- a/pantograph/search.py
+++ b/pantograph/search.py
@@ -1,5 +1,5 @@
 from dataclasses import dataclass
-from typing import override, Optional
+from typing import  Optional
 import collections, unittest
 
 from pantograph.server import Server, TacticFailure
@@ -140,7 +140,6 @@ class DumbAgent(Agent):
             "assumption",
         ]
 
-    @override
     def next_tactic(self, state: GoalState, goal_id: int) -> Optional[Tactic]:
         key = (state.state_id, goal_id)
         i = self.goal_tactic_id_map[key]
diff --git a/pantograph/search_llm.py b/pantograph/search_llm.py
index c0a8bee..d0a8174 100644
--- a/pantograph/search_llm.py
+++ b/pantograph/search_llm.py
@@ -1,17 +1,18 @@
-import search
-from dataclasses import dataclass
-from typing import override, Optional
+from typing import Optional
 import collections, unittest
-
+from pantograph.search import Agent
 from pantograph.server import Server, TacticFailure, ServerError
 from pantograph.expr import Expr, Tactic, GoalState
 from pantograph.gen_tactic import LEAN4_REWRITE, select_tactic
+import sglang as sgl 
 
-class LLMAgent(search.Agent):
+class LLMAgent(Agent):
 
-    def __init__(self):
+    def __init__(self, server):
         super().__init__()
         self.n_trials = 5
+        self.server = server
+        sgl.set_default_backend(sgl.OpenAI("gpt-4"))
 
         self.goal_tactic_id_map = collections.defaultdict(lambda : 0)
         self.intros = [
@@ -27,7 +28,6 @@ class LLMAgent(search.Agent):
             "assumption",
         ]
 
-    @override
     def next_tactic(self, state: GoalState, goal_id: int) -> Optional[Tactic]:
         key = (state.state_id, goal_id)
         i = self.goal_tactic_id_map[key]
@@ -45,19 +45,44 @@ class LLMAgent(search.Agent):
 
         self.goal_tactic_id_map[key] = i + 1
         new_state = None
-        for i in range(self.n_trails):
-            print(f"===============trail {str(i)}============")
+        for ii in range(self.n_trials):
+            print(f"===============trail {str(ii)}============")
             try:
-                state = select_tactic.run(self.server, state, goal_id = 1)
+                state = select_tactic.run(server = self.server, state=state, goal_id = goal_id)
                 tactic, new_state = state.ret_value
                 for m in state.messages():
                     print(m["role"], ":", m["content"])
 
                 print("\n-- new state --\n", new_state)
-                break
+                if tactic:
+                    return tactic
                 
             except ServerError as e:
                 print(f"server error: {e}")
                 continue
+            except TacticFailure as e:
+                print(f"tactic failure: {e}")
+                continue
+        
 
         return tactics[i]
+
+class TestSearch(unittest.TestCase):
+
+    def test_solve(self):
+
+        server = Server()
+        agent = LLMAgent(server)
+        flag = agent.search(server=server, target="∀ (p q: Prop), p -> p", verbose=True)
+        #flag = agent.search(server=server, target="∀ (p q: Prop), Or p q -> Or q p", verbose=True)
+        self.assertTrue(flag)
+    def test_solve_big(self):
+
+        server = Server()
+        agent = LLMAgent(server)
+        flag = agent.search(server=server, target="∀ (p q: Prop), Or p q -> Or q p", verbose=True)
+        self.assertTrue(flag)
+
+
+if __name__ == '__main__':
+    unittest.main()