diff --git a/Pantograph/Goal.lean b/Pantograph/Goal.lean
index 52562e7..6ff14d2 100644
--- a/Pantograph/Goal.lean
+++ b/Pantograph/Goal.lean
@@ -244,12 +244,13 @@ protected def GoalState.tryTacticM (state: GoalState) (goal: MVarId) (tacticM: E
     let nextState ← state.step goal tacticM guardMVarErrors
 
     -- Check if error messages have been generated in the core.
-    let newMessages ← (← Core.getMessageLog).toList --.drop state.coreState.messages.toList.length
+    let newMessages ← (← Core.getMessageLog).toList.drop state.coreState.messages.toList.length
       |>.filterMapM λ m => do
         if m.severity == .error then
           return .some $ ← m.toString
         else
           return .none
+    Core.resetMessageLog
     if ¬ newMessages.isEmpty then
       return .failure newMessages.toArray
     return .success nextState
diff --git a/Repl.lean b/Repl.lean
index 283bcf3..2060061 100644
--- a/Repl.lean
+++ b/Repl.lean
@@ -79,6 +79,7 @@ def execute (command: Protocol.Command): MainM Lean.Json := do
     let state ← get
     let nGoals := state.goalStates.size
     set { state with nextId := 0, goalStates := .empty }
+    Lean.Core.resetMessageLog
     return .ok { nGoals }
   stat (_: Protocol.Stat): MainM (CR Protocol.StatResult) := do
     let state ← get