diff --git a/crates/bin/cairo-execute/src/main.rs b/crates/bin/cairo-execute/src/main.rs
index f0db53f4782..38e4922d9dc 100644
--- a/crates/bin/cairo-execute/src/main.rs
+++ b/crates/bin/cairo-execute/src/main.rs
@@ -7,6 +7,7 @@ use cairo_lang_compiler::diagnostics::DiagnosticsReporter;
 use cairo_lang_compiler::project::check_compiler_path;
 use cairo_lang_executable::compile::compile_executable;
 use cairo_lang_executable::executable::{EntryPointKind, Executable};
+use cairo_lang_runner::casm_run::format_for_panic;
 use cairo_lang_runner::{Arg, CairoHintProcessor, build_hints_dict};
 use cairo_lang_utils::bigint::BigUintAsHex;
 use cairo_vm::cairo_run::{CairoRunConfig, cairo_run_program};
@@ -225,6 +226,7 @@ fn main() -> anyhow::Result<()> {
         run_resources: Default::default(),
         syscalls_used_resources: Default::default(),
         no_temporary_segments: false,
+        markers: Default::default(),
     };
 
     let cairo_run_config = CairoRunConfig {
@@ -243,6 +245,16 @@ fn main() -> anyhow::Result<()> {
         let mut output_buffer = "Program Output:\n".to_string();
         runner.vm.write_output(&mut output_buffer)?;
         print!("{output_buffer}");
+        if let [.., start_marker, end_marker] = &hint_processor.markers[..] {
+            let size = (*end_marker - *start_marker).with_context(|| {
+                format!("Panic data markers mismatch: start={start_marker}, end={end_marker}")
+            })?;
+            let panic_data = runner
+                .vm
+                .get_integer_range(*start_marker, size)
+                .with_context(|| "Failed reading panic data.")?;
+            println!("{}", format_for_panic(panic_data.into_iter().map(|value| *value)));
+        }
     }
 
     if let Some(trace_path) = &args.run.standalone_outputs.trace_file {
diff --git a/crates/cairo-lang-casm/src/hints/mod.rs b/crates/cairo-lang-casm/src/hints/mod.rs
index 1304242d163..9812dc62ab3 100644
--- a/crates/cairo-lang-casm/src/hints/mod.rs
+++ b/crates/cairo-lang-casm/src/hints/mod.rs
@@ -354,6 +354,9 @@ pub enum ExternalHint {
     /// Writes a run argument of number `index` to `dst` and on.
     #[cfg_attr(feature = "parity-scale-codec", codec(index = 1))]
     WriteRunParam { index: ResOperand, dst: CellRef },
+    /// Stores a marker in the HintProcessor. Useful for debugging.
+    #[cfg_attr(feature = "parity-scale-codec", codec(index = 2))]
+    SetMarker { marker: ResOperand },
 }
 
 struct DerefOrImmediateFormatter<'a>(&'a DerefOrImmediate);
@@ -850,6 +853,10 @@ impl PythonicHint for ExternalHint {
                 let index = ResOperandAsIntegerFormatter(index);
                 format!(r#"raise NotImplementedError("memory{dst}.. = params[{index}])")"#)
             }
+            Self::SetMarker { marker } => {
+                let marker = ResOperandAsAddressFormatter(marker);
+                format!(r#"raise NotImplementedError("marker = {}")"#, marker)
+            }
         }
     }
 }
diff --git a/crates/cairo-lang-executable/src/compile_test_data/basic b/crates/cairo-lang-executable/src/compile_test_data/basic
index b58fc6f7858..7176b773d79 100644
--- a/crates/cairo-lang-executable/src/compile_test_data/basic
+++ b/crates/cairo-lang-executable/src/compile_test_data/basic
@@ -18,6 +18,8 @@ call rel 12;
 jmp rel 5 if [ap + -3] != 0, ap++;
 [ap + -1] = [ap + -2];
 jmp rel 4;
+%{ raise NotImplementedError("marker = memory[ap + -3]") %}
+%{ raise NotImplementedError("marker = memory[ap + -2]") %}
 [ap + -1] = [fp + -3] + 1;
 [ap + -4] = [[fp + -3] + 0];
 [ap + 0] = [ap + -1], ap++;
@@ -68,6 +70,8 @@ call rel 12;
 jmp rel 5 if [ap + -3] != 0, ap++;
 [ap + -1] = [ap + -2];
 jmp rel 4;
+%{ raise NotImplementedError("marker = memory[ap + -3]") %}
+%{ raise NotImplementedError("marker = memory[ap + -2]") %}
 [ap + -1] = [fp + -3] + 1;
 [ap + -4] = [[fp + -3] + 0];
 [ap + 0] = [ap + -1], ap++;
@@ -155,6 +159,8 @@ call rel 13;
 jmp rel 5 if [ap + -3] != 0, ap++;
 [ap + -1] = [ap + -2];
 jmp rel 4;
+%{ raise NotImplementedError("marker = memory[ap + -3]") %}
+%{ raise NotImplementedError("marker = memory[ap + -2]") %}
 [ap + -1] = [fp + -4] + 1;
 [ap + -4] = [[fp + -4] + 0];
 [ap + 0] = [ap + -1], ap++;
@@ -428,6 +434,8 @@ call rel 12;
 jmp rel 5 if [ap + -3] != 0, ap++;
 [ap + -1] = [ap + -2];
 jmp rel 4;
+%{ raise NotImplementedError("marker = memory[ap + -3]") %}
+%{ raise NotImplementedError("marker = memory[ap + -2]") %}
 [ap + -1] = [fp + -3] + 1;
 [ap + -4] = [[fp + -3] + 0];
 [ap + 0] = [ap + -1], ap++;
@@ -490,6 +498,8 @@ call rel 39;
 jmp rel 5 if [ap + -3] != 0, ap++;
 [ap + -1] = [ap + -2];
 jmp rel 4;
+%{ raise NotImplementedError("marker = memory[ap + -3]") %}
+%{ raise NotImplementedError("marker = memory[ap + -2]") %}
 [ap + -1] = [fp + -4] + 1;
 [ap + -4] = [[fp + -4] + 0];
 [fp + 0] = [ap + -7];
diff --git a/crates/cairo-lang-runnable-utils/src/builder.rs b/crates/cairo-lang-runnable-utils/src/builder.rs
index d984aa4f5c1..8b5feeee88f 100644
--- a/crates/cairo-lang-runnable-utils/src/builder.rs
+++ b/crates/cairo-lang-runnable-utils/src/builder.rs
@@ -413,34 +413,40 @@ pub fn create_entry_code_from_params(
     }
     casm_build_extend! (ctx, let () = call FUNCTION;);
     let mut unprocessed_return_size = return_types.iter().map(|(_, size)| size).sum::<i16>();
+    let mut next_unprocessed_deref = || {
+        let deref_cell = CellExpression::Deref(deref!([ap - unprocessed_return_size]));
+        unprocessed_return_size -= 1;
+        deref_cell
+    };
     let mut return_data = vec![];
     for (ret_ty, size) in return_types {
         if let Some(name) = builtin_ty_to_vm_name.get(ret_ty) {
-            *builtin_vars.get_mut(name).unwrap() =
-                ctx.add_var(CellExpression::Deref(deref!([ap - unprocessed_return_size])));
-            unprocessed_return_size -= 1;
+            *builtin_vars.get_mut(name).unwrap() = ctx.add_var(next_unprocessed_deref());
         } else if config.outputting_function {
             if ret_ty == &GasBuiltinType::ID {
-                unprocessed_return_size -= 1;
+                next_unprocessed_deref();
                 continue;
             }
             let output_ptr_var = builtin_vars[&BuiltinName::output];
             // The output builtin values.
             let new_output_ptr = if *size == 3 {
-                let panic_indicator =
-                    ctx.add_var(CellExpression::Deref(deref!([ap - unprocessed_return_size])));
-                unprocessed_return_size -= 2;
-                // The output ptr in the case of successful run.
-                let output_ptr_end =
-                    ctx.add_var(CellExpression::Deref(deref!([ap - unprocessed_return_size])));
-                unprocessed_return_size -= 1;
+                let panic_indicator = ctx.add_var(next_unprocessed_deref());
+                // The start ptr of the output in the case of successful run,
+                // or the panic data in case of a failure.
+                let ptr_start = ctx.add_var(next_unprocessed_deref());
+                // The end ptr of the output in the case of successful run,
+                // or the panic data in case of a failure.
+                let ptr_end = ctx.add_var(next_unprocessed_deref());
                 casm_build_extend! {ctx,
                     tempvar new_output_ptr;
                     jump PANIC if panic_indicator != 0;
                     // SUCCESS:
-                    assert new_output_ptr = output_ptr_end;
+                    assert new_output_ptr = ptr_end;
                     jump AFTER_PANIC_HANDLING;
                     PANIC:
+                    // Marking the panic message in case of a panic.
+                    hint ExternalHint::SetMarker { marker: ptr_start };
+                    hint ExternalHint::SetMarker { marker: ptr_end };
                     const one = 1;
                     // In the case of an error, we assume no values are written to the output_ptr.
                     assert new_output_ptr = output_ptr_var + one;
@@ -450,10 +456,8 @@ pub fn create_entry_code_from_params(
                 new_output_ptr
             } else if *size == 2 {
                 // No panic possible.
-                unprocessed_return_size -= 1;
-                let output_ptr_end =
-                    ctx.add_var(CellExpression::Deref(deref!([ap - unprocessed_return_size])));
-                unprocessed_return_size -= 1;
+                next_unprocessed_deref();
+                let output_ptr_end = ctx.add_var(next_unprocessed_deref());
                 casm_build_extend! {ctx,
                     const czero = 0;
                     tempvar zero = czero;
@@ -466,10 +470,7 @@ pub fn create_entry_code_from_params(
             *builtin_vars.get_mut(&BuiltinName::output).unwrap() = new_output_ptr;
         } else {
             for _ in 0..*size {
-                return_data.push(
-                    ctx.add_var(CellExpression::Deref(deref!([ap - unprocessed_return_size]))),
-                );
-                unprocessed_return_size -= 1;
+                return_data.push(ctx.add_var(next_unprocessed_deref()));
             }
         }
     }
diff --git a/crates/cairo-lang-runner/src/casm_run/mod.rs b/crates/cairo-lang-runner/src/casm_run/mod.rs
index 111c2dfa58e..20940179632 100644
--- a/crates/cairo-lang-runner/src/casm_run/mod.rs
+++ b/crates/cairo-lang-runner/src/casm_run/mod.rs
@@ -102,6 +102,8 @@ pub struct CairoHintProcessor<'a> {
     pub syscalls_used_resources: StarknetExecutionResources,
     /// Avoid allocating memory segments so finalization of segment arena may not occur.
     pub no_temporary_segments: bool,
+    /// A set of markers created by the run.
+    pub markers: Vec<Relocatable>,
 }
 
 pub fn cell_ref_to_relocatable(cell_ref: &CellRef, vm: &VirtualMachine) -> Relocatable {
@@ -1306,15 +1308,15 @@ impl CairoHintProcessor<'_> {
 
     /// Executes an external hint.
     fn execute_external_hint(
-        &self,
+        &mut self,
         vm: &mut VirtualMachine,
         core_hint: &ExternalHint,
     ) -> Result<(), HintError> {
         match core_hint {
-            ExternalHint::AddRelocationRule { src, dst } => Ok(vm.add_relocation_rule(
+            ExternalHint::AddRelocationRule { src, dst } => vm.add_relocation_rule(
                 extract_relocatable(vm, src)?,
                 extract_relocatable(vm, dst)?,
-            )?),
+            )?,
             ExternalHint::WriteRunParam { index, dst } => {
                 let index = get_val(vm, index)?.to_usize().expect("Got a bad index.");
                 let mut stack = vec![(cell_ref_to_relocatable(dst, vm), &self.user_args[index])];
@@ -1336,9 +1338,12 @@ impl CairoHintProcessor<'_> {
                         }
                     }
                 }
-                Ok(())
+            }
+            ExternalHint::SetMarker { marker } => {
+                self.markers.push(extract_relocatable(vm, marker)?);
             }
         }
+        Ok(())
     }
 }
 
@@ -2378,6 +2383,20 @@ where
     Some(FormattedItem { item: format_short_string(&first_felt), is_string: false })
 }
 
+/// Formats the given felts as a panic string.
+pub fn format_for_panic<T>(mut felts: T) -> String
+where
+    T: Iterator<Item = Felt252> + Clone,
+{
+    let mut items = Vec::new();
+    while let Some(item) = format_next_item(&mut felts) {
+        items.push(item.quote_if_string());
+    }
+    let panic_values_string =
+        if let [item] = &items[..] { item.clone() } else { format!("({})", items.join(", ")) };
+    format!("Panicked with {panic_values_string}.")
+}
+
 /// Formats a `Felt252`, as a short string if possible.
 fn format_short_string(value: &Felt252) -> String {
     let hex_value = value.to_biguint();
diff --git a/crates/cairo-lang-runner/src/casm_run/test.rs b/crates/cairo-lang-runner/src/casm_run/test.rs
index bf32b65e00b..6eaf881600d 100644
--- a/crates/cairo-lang-runner/src/casm_run/test.rs
+++ b/crates/cairo-lang-runner/src/casm_run/test.rs
@@ -130,6 +130,7 @@ fn test_runner(function: CasmContext, n_returns: usize, expected: &[i128]) {
         run_resources: RunResources::default(),
         syscalls_used_resources: Default::default(),
         no_temporary_segments: true,
+        markers: Default::default(),
     };
 
     let RunFunctionResult { ap, memory, .. } =
@@ -159,6 +160,7 @@ fn test_allocate_segment() {
         run_resources: RunResources::default(),
         syscalls_used_resources: Default::default(),
         no_temporary_segments: true,
+        markers: Default::default(),
     };
 
     let RunFunctionResult { ap, memory, .. } =
diff --git a/crates/cairo-lang-runner/src/lib.rs b/crates/cairo-lang-runner/src/lib.rs
index 37b10ec9e95..38423dc5665 100644
--- a/crates/cairo-lang-runner/src/lib.rs
+++ b/crates/cairo-lang-runner/src/lib.rs
@@ -207,6 +207,7 @@ impl SierraCasmRunner {
             run_resources: RunResources::default(),
             syscalls_used_resources: Default::default(),
             no_temporary_segments: true,
+            markers: Default::default(),
         };
         let RunResult { gas_counter, memory, value, used_resources, profiling_info } = self
             .run_function(
diff --git a/crates/cairo-lang-test-runner/src/lib.rs b/crates/cairo-lang-test-runner/src/lib.rs
index cfffdc61f6c..3952ec99bd7 100644
--- a/crates/cairo-lang-test-runner/src/lib.rs
+++ b/crates/cairo-lang-test-runner/src/lib.rs
@@ -1,6 +1,5 @@
 use std::path::Path;
 use std::sync::Mutex;
-use std::vec::IntoIter;
 
 use anyhow::{Context, Result, bail};
 use cairo_lang_compiler::db::RootDatabase;
@@ -8,7 +7,7 @@ use cairo_lang_compiler::diagnostics::DiagnosticsReporter;
 use cairo_lang_compiler::project::setup_project;
 use cairo_lang_filesystem::cfg::{Cfg, CfgSet};
 use cairo_lang_filesystem::ids::CrateId;
-use cairo_lang_runner::casm_run::format_next_item;
+use cairo_lang_runner::casm_run::format_for_panic;
 use cairo_lang_runner::profiling::{
     ProfilingInfo, ProfilingInfoProcessor, ProfilingInfoProcessorParams,
 };
@@ -165,17 +164,6 @@ impl CompiledTestRunner {
     }
 }
 
-/// Formats the given felts as a panic string.
-fn format_for_panic(mut felts: IntoIter<Felt252>) -> String {
-    let mut items = Vec::new();
-    while let Some(item) = format_next_item(&mut felts) {
-        items.push(item.quote_if_string());
-    }
-    let panic_values_string =
-        if let [item] = &items[..] { item.clone() } else { format!("({})", items.join(", ")) };
-    format!("Panicked with {panic_values_string}.")
-}
-
 /// Whether to run the profiler, and what results to produce.
 ///
 /// With `None`, don't run the profiler.
diff --git a/crates/cairo-lang-test-runner/src/test.rs b/crates/cairo-lang-test-runner/src/test.rs
index df4f2db9edb..8504c817362 100644
--- a/crates/cairo-lang-test-runner/src/test.rs
+++ b/crates/cairo-lang-test-runner/src/test.rs
@@ -1,3 +1,4 @@
+use cairo_lang_runner::casm_run::format_for_panic;
 use cairo_lang_sierra::program::{Program, ProgramArtifact};
 use cairo_lang_test_plugin::test_config::TestExpectation;
 use cairo_lang_test_plugin::{TestCompilationMetadata, TestConfig, TestsCompilationConfig};
@@ -5,7 +6,7 @@ use cairo_lang_utils::byte_array::BYTE_ARRAY_MAGIC;
 use itertools::Itertools;
 use starknet_types_core::felt::Felt as Felt252;
 
-use crate::{TestCompilation, TestCompiler, filter_test_cases, format_for_panic};
+use crate::{TestCompilation, TestCompiler, filter_test_cases};
 
 #[test]
 fn test_compiled_serialization() {