diff --git a/pantograph/server.py b/pantograph/server.py
index 85bc436..28fc63b 100644
--- a/pantograph/server.py
+++ b/pantograph/server.py
@@ -65,8 +65,8 @@ class Server:
             raise ServerError(result["desc"])
         return GoalState(state_id = result["stateId"], goals = [Goal.sentence(expr)])
 
-    def goal_tactic(self, state: GoalState, goalId: int, tactic: Tactic) -> GoalState:
-        args = { "stateId": state.state_id, "goalId": goalId }
+    def goal_tactic(self, state: GoalState, goal_id: int, tactic: Tactic) -> GoalState:
+        args = { "stateId": state.state_id, "goalId": goal_id}
         if isinstance(tactic, TacticNormal):
             args["tactic"] = tactic.payload
         else:
@@ -99,7 +99,7 @@ class TestServer(unittest.TestCase):
         server = Server()
         state0 = server.goal_start("forall (p q: Prop), Or p q -> Or q p")
         self.assertEqual(state0.state_id, 0)
-        state1 = server.goal_tactic(state0, goalId=0, tactic=TacticNormal("intro a"))
+        state1 = server.goal_tactic(state0, goal_id=0, tactic=TacticNormal("intro a"))
         self.assertEqual(state1.state_id, 1)
         self.assertEqual(state1.goals, [Goal(
             variables=[Variable(name="a", t="Prop")],