diff --git a/experiments/minif2f/.gitignore b/experiments/minif2f/.gitignore
new file mode 100644
index 0000000..55ac6ac
--- /dev/null
+++ b/experiments/minif2f/.gitignore
@@ -0,0 +1 @@
+/output*
diff --git a/experiments/minif2f/README.md b/experiments/minif2f/README.md
index ad72c20..560eb4d 100644
--- a/experiments/minif2f/README.md
+++ b/experiments/minif2f/README.md
@@ -1,11 +1,14 @@
 # MiniF2F
 
-This is an experiment on running a LLM prover on miniF2F data. Run with
+This is an experiment on running a LLM prover on miniF2F data. Build the project
+`MiniF2F` with `lake build`, and run with
 
 ```sh
-python3 experiments/minif2f/main.py [--dry-run]
+python3 experiments/minif2f/main.py [--dry-run] [--use-llm]
 ```
 
+Read the help message carefully.
+
 ## Developing
 
 Run unit tests with
diff --git a/experiments/minif2f/main.py b/experiments/minif2f/main.py
index 4186348..ea1fd50 100755
--- a/experiments/minif2f/main.py
+++ b/experiments/minif2f/main.py
@@ -72,9 +72,10 @@ def run_eval(args):
         if file_name.is_file():
             print(f"Skipping {datum['id']}")
             continue
-        server = Server(imports=["MiniF2F"], project_path=project_path, lean_path=lean_path, core_options=["maxHeartbeats=0"])
+        server = Server(imports=["MiniF2F"], project_path=project_path, lean_path=lean_path)
         agent = LLMAgent(server, use_hammer=args.use_hammer, use_llm=args.use_llm)
         result = try_test_data(server, agent, datum, max_steps=args.max_steps, max_trials_per_goal=args.max_trials_per_goal)
+        #server.gc()
         if result is None:
             with open(placeholder_file_name, 'w') as f:
                 json.dump({ 'id': datum['id'] }, f)
diff --git a/pantograph/server.py b/pantograph/server.py
index e0f6870..a94b593 100644
--- a/pantograph/server.py
+++ b/pantograph/server.py
@@ -28,8 +28,8 @@ class Server:
                  # Options for executing the REPL.
                  # Set `{ "automaticMode" : False }` to handle resumption by yourself.
                  options={},
-                 core_options=[],
-                 timeout=20,
+                 core_options=["maxHeartbeats=0"],
+                 timeout=60,
                  maxread=1000000):
         """
         timeout: Amount of time to wait for execution
@@ -86,7 +86,10 @@ class Server:
         self.proc.sendline(f"{cmd} {s}")
         try:
             line = self.proc.readline()
-            return json.loads(line)
+            try:
+                return json.loads(line)
+            except Exception as e:
+                raise ServerError(f"Cannot decode: {line}") from e
         except pexpect.exceptions.TIMEOUT as exc:
             raise exc
 
@@ -96,9 +99,12 @@ class Server:
 
         Must be called periodically.
         """
-        if self.to_remove_goal_states:
-            self.run('goal.delete', {'stateIds': self.to_remove_goal_states})
-            self.to_remove_goal_states.clear()
+        if not self.to_remove_goal_states:
+            return
+        result = self.run('goal.delete', {'stateIds': self.to_remove_goal_states})
+        self.to_remove_goal_states.clear()
+        if "error" in result:
+            raise ServerError(result["desc"])
 
     def expr_type(self, expr: Expr) -> Expr:
         """