diff --git a/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologCmd.kt b/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologCmd.kt
index d452c584e..ffa2cb990 100644
--- a/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologCmd.kt
+++ b/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologCmd.kt
@@ -12,6 +12,7 @@ import it.unibo.tuprolog.core.parsing.ParseException
 import it.unibo.tuprolog.core.parsing.parse
 import it.unibo.tuprolog.solve.Solver
 import it.unibo.tuprolog.solve.TimeDuration
+import it.unibo.tuprolog.solve.channel.OutputChannel
 import it.unibo.tuprolog.solve.classicWithDefaultBuiltins
 import it.unibo.tuprolog.theory.Theory
 
@@ -43,7 +44,6 @@ class TuPrologCmd : CliktCommand(
         if (subcommand == null) {
             readEvalPrintLoop(solve)
         }
-        // nota: se subcommand è diverso da null, il controllo fluisce automaticamente al metodo run di subcommand
     }
 
     private fun loadTheory(): Theory {
@@ -55,13 +55,15 @@ class TuPrologCmd : CliktCommand(
                     TermUi.echo("# Successfully loaded ${t.size} clauses from $file")
                     theory += t
                 } catch (e: ParseException) {
-                    TermUi.echo("""
-                        |Error while parsing theory file: $file
-                        |    Message: ${e.message}
-                        |    Line   : ${e.line}
-                        |    Column : ${e.column}
-                        |    Clause : ${e.clauseIndex}
-                    """.trimMargin(), err = true)
+                    TermUi.echo(
+                        """
+                        |# Error while parsing theory file: $file
+                        |#     Message: ${e.message}
+                        |#     Line   : ${e.line}
+                        |#     Column : ${e.column}
+                        |#     Clause : ${e.clauseIndex}
+                    """.trimMargin(), err = true
+                    )
                 }
             }
         }
@@ -91,7 +93,12 @@ class TuPrologCmd : CliktCommand(
     fun getSolver(): Solver {
         TermUi.echo("# 2P-Kt version ${Info.VERSION}")
         val theory: Theory = this.loadTheory()
-        return Solver.classicWithDefaultBuiltins(staticKb = theory)
+        return Solver.classicWithDefaultBuiltins(
+            staticKb = theory,
+            warnings = OutputChannel.of {
+                TermUi.echo("# ${it.message}", err = true)
+            }
+        )
     }
 }
 
diff --git a/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologUtils.kt b/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologUtils.kt
index f8b3bc11a..d7d74d730 100644
--- a/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologUtils.kt
+++ b/repl/src/commonMain/kotlin/it/unibo/tuprolog/ui/repl/TuPrologUtils.kt
@@ -29,12 +29,12 @@ object TuPrologUtils {
     }
 
     private fun printYesSolution(sol: Solution.Yes, operatorSet: OperatorSet) {
-        TermUi.echo("yes: ${sol.solvedQuery.format(prettyExpressions(operatorSet))}.")
+        val formatter = prettyExpressions(operatorSet)
+        TermUi.echo("yes: ${sol.solvedQuery.format(formatter)}.")
         if (sol.substitution.isNotEmpty()) {
-            val sep = "\n    "
-            val substitutions = sol.substitution.entries.joinToString(sep) {
-                val prettyVariable = it.key.format(TermFormatter.prettyVariables())
-                val prettyValue = it.value.format(prettyExpressions(operatorSet))
+            val substitutions = sol.substitution.entries.joinToString("\n    ") {
+                val prettyVariable = it.key.format(formatter)
+                val prettyValue = it.value.format(formatter)
                 "$prettyVariable = $prettyValue"
             }
             TermUi.echo("    $substitutions")
@@ -57,14 +57,15 @@ object TuPrologUtils {
                     TermUi.echo("halt: ${ex.message?.trim()}")
                 }
                 val sep = "\n    at "
-                val stacktrace = ex.prologStackTrace.joinToString(sep) { it.format(prettyExpressions(operatorSet)) }
+                val formatter = prettyExpressions(operatorSet)
+                val stacktrace = ex.prologStackTrace.joinToString(sep) { it.format(formatter) }
                 TermUi.echo("    at $stacktrace")
             }
         }
     }
 
     fun printParseException(e: ParseException) {
-        TermUi.echo(e.message?.capitalize(), err = true)
+        TermUi.echo("# ${e.message?.capitalize()}", err = true)
     }
 
     private fun printEndOfSolutions() {