From 80686d6ed1e6e2d2eebd2712648c2daeed3f01d5 Mon Sep 17 00:00:00 2001
From: Anand Krishnamoorthi <35780660+anakrish@users.noreply.github.com>
Date: Tue, 20 Jan 2026 21:50:10 -0600
Subject: [PATCH] feat(ffi): unwind safety: shield FFI entrypoints with panic
 guard (#546)

This PR implements widely accepted Rust programming practices for
dealing with panics across ABI (programming language) boundaries.

- Add panic_guard.rs to wrap FFI calls and prevent panic across FFI/ABI boundary (undefined behavior).
- Capture per-thread backtraces via a temporary panic hook
- After a panic, subsequent invocations are poisoned.
- Integrate with_unwind_guard across the engine, schema registry, and target registry exportis

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
---
 .github/workflows/test-csharp.yml             |   4 +-
 .../csharp/Regorus.Tests/PanicGuardTests.cs   |  84 +++
 .../csharp/Regorus.Tests/Regorus.Tests.csproj |  16 +-
 bindings/csharp/Regorus/AssemblyInfo.cs       |   3 +
 bindings/csharp/Regorus/CompiledPolicy.cs     |   3 +-
 bindings/csharp/Regorus/Compiler.cs           |   2 +-
 bindings/csharp/Regorus/Engine.cs             |  24 +-
 bindings/csharp/Regorus/NativeMethods.cs      |  22 +
 bindings/csharp/Regorus/Regorus.csproj        |   4 +
 bindings/csharp/Regorus/SchemaRegistry.cs     |   6 +-
 bindings/csharp/Regorus/StatusExtensions.cs   |  24 +
 bindings/csharp/Regorus/TargetRegistry.cs     |   6 +-
 bindings/ffi/src/common.rs                    |   6 +
 bindings/ffi/src/compile.rs                   | 157 +++--
 bindings/ffi/src/compiled_policy.rs           |  45 +-
 bindings/ffi/src/effect_registry.rs           | 157 ++---
 bindings/ffi/src/engine.rs                    | 546 +++++++++++-------
 bindings/ffi/src/lib.rs                       |   1 +
 bindings/ffi/src/panic_guard.rs               | 159 +++++
 bindings/ffi/src/schema_registry.rs           | 157 ++---
 bindings/ffi/src/target_registry.rs           |  83 +--
 21 files changed, 1008 insertions(+), 501 deletions(-)
 create mode 100644 bindings/csharp/Regorus.Tests/PanicGuardTests.cs
 create mode 100644 bindings/csharp/Regorus/AssemblyInfo.cs
 create mode 100644 bindings/csharp/Regorus/StatusExtensions.cs
 create mode 100644 bindings/ffi/src/panic_guard.rs

diff --git a/.github/workflows/test-csharp.yml b/.github/workflows/test-csharp.yml
index d0e2d43..f6b4c9b 100644
--- a/.github/workflows/test-csharp.yml
+++ b/.github/workflows/test-csharp.yml
@@ -144,11 +144,11 @@ jobs:
           path: ./bindings/csharp/regorus-nuget/
 
       - name: Restore Regorus.Tests
-        run: dotnet restore /p:RestoreAdditionalProjectSources=../regorus-nuget
+        run: dotnet restore /p:RestoreAdditionalProjectSources=../regorus-nuget /p:UseLocalRegorus=false
         working-directory: ./bindings/csharp/Regorus.Tests
 
       - name: Run Regorus.Tests
-        run: dotnet test --no-restore
+        run: dotnet test --no-restore -p:UseLocalRegorus=false
         working-directory: ./bindings/csharp/Regorus.Tests
 
       - name: Restore TestApp
diff --git a/bindings/csharp/Regorus.Tests/PanicGuardTests.cs b/bindings/csharp/Regorus.Tests/PanicGuardTests.cs
new file mode 100644
index 0000000..3549afa
--- /dev/null
+++ b/bindings/csharp/Regorus.Tests/PanicGuardTests.cs
@@ -0,0 +1,84 @@
+#if REGORUS_FFI_TEST_HOOKS
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Runtime.InteropServices;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Regorus.Internal;
+
+namespace Regorus.Tests;
+
+[TestClass]
+public sealed class PanicGuardTests
+{
+    [TestInitialize]
+    public void Initialize()
+    {
+        API.regorus_engine_test_reset_poison();
+    }
+
+    [TestCleanup]
+    public void Cleanup()
+    {
+        API.regorus_engine_test_reset_poison();
+    }
+
+    [TestMethod]
+    public void Panic_produces_invalid_operation_exception()
+    {
+        var panic = Assert.ThrowsException<InvalidOperationException>(TriggerPanic);
+        StringAssert.Contains(panic.Message, "panicked", "panic message should capture payload");
+    }
+
+    [TestMethod]
+    public void Poison_flag_blocks_subsequent_calls()
+    {
+        _ = Assert.ThrowsException<InvalidOperationException>(TriggerPanic);
+        var poisoned = Assert.ThrowsException<InvalidOperationException>(TriggerPanic);
+        StringAssert.Contains(poisoned.Message, "poisoned", "poisoned message should explain guard state");
+    }
+
+    private static unsafe void TriggerPanic()
+    {
+        var result = API.regorus_engine_test_trigger_panic();
+        try
+        {
+            if (result.status == RegorusStatus.Ok)
+            {
+                return;
+            }
+
+            var message = PtrToStringUtf8((IntPtr)result.error_message);
+            throw result.status.CreateException(message);
+        }
+        finally
+        {
+            API.regorus_result_drop(result);
+        }
+    }
+
+    private static string? PtrToStringUtf8(IntPtr ptr)
+    {
+#if NETSTANDARD2_1
+        return Marshal.PtrToStringUTF8(ptr);
+#else
+        if (ptr == IntPtr.Zero)
+        {
+            return null;
+        }
+
+        var len = 0;
+        while (Marshal.ReadByte(ptr, len) != 0)
+        {
+            len++;
+        }
+
+        var buffer = new byte[len];
+        Marshal.Copy(ptr, buffer, 0, buffer.Length);
+        return System.Text.Encoding.UTF8.GetString(buffer);
+#endif
+    }
+}
+
+#endif
diff --git a/bindings/csharp/Regorus.Tests/Regorus.Tests.csproj b/bindings/csharp/Regorus.Tests/Regorus.Tests.csproj
index 6130a90..a1add44 100644
--- a/bindings/csharp/Regorus.Tests/Regorus.Tests.csproj
+++ b/bindings/csharp/Regorus.Tests/Regorus.Tests.csproj
@@ -6,11 +6,17 @@
     <!-- More info about dotnet test integration https://learn.microsoft.com/dotnet/core/testing/unit-testing-platform-integration-dotnet-test -->
     <TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport>
     <TestingPlatformShowTestsFailure>true</TestingPlatformShowTestsFailure>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   
   <PropertyGroup>
     <!-- If the environment variable is set (such as in a Github Action run), append the suffix to the version number -->
     <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
+    <UseLocalRegorus Condition="'$(UseLocalRegorus)' == ''">true</UseLocalRegorus>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(UseLocalRegorus)' == 'true'">
+    <DefineConstants>$(DefineConstants);REGORUS_FFI_TEST_HOOKS</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
@@ -21,7 +27,13 @@
     <PackageReference Include="MSTest" Version="3.8.2" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Regorus" Version="0.8.0$(RegorusPackageVersionSuffix)"/>
+  <ItemGroup Condition="'$(UseLocalRegorus)' == 'true'">
+    <ProjectReference Include="../Regorus/Regorus.csproj">
+      <AdditionalProperties>EnableRegorusTestHooks=true</AdditionalProperties>
+    </ProjectReference>
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(UseLocalRegorus)' != 'true'">
+    <PackageReference Include="Regorus" Version="0.8.0$(RegorusPackageVersionSuffix)" />
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/bindings/csharp/Regorus/AssemblyInfo.cs b/bindings/csharp/Regorus/AssemblyInfo.cs
new file mode 100644
index 0000000..c6822d8
--- /dev/null
+++ b/bindings/csharp/Regorus/AssemblyInfo.cs
@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Regorus.Tests")]
diff --git a/bindings/csharp/Regorus/CompiledPolicy.cs b/bindings/csharp/Regorus/CompiledPolicy.cs
index 266afac..0673192 100644
--- a/bindings/csharp/Regorus/CompiledPolicy.cs
+++ b/bindings/csharp/Regorus/CompiledPolicy.cs
@@ -5,6 +5,7 @@ using System;
 using System.Text;
 using System.Text.Json;
 using System.Threading;
+using Regorus.Internal;
 
 #nullable enable
 namespace Regorus
@@ -165,7 +166,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type switch
diff --git a/bindings/csharp/Regorus/Compiler.cs b/bindings/csharp/Regorus/Compiler.cs
index 3870bac..1c8c187 100644
--- a/bindings/csharp/Regorus/Compiler.cs
+++ b/bindings/csharp/Regorus/Compiler.cs
@@ -177,7 +177,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown compilation error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 if (result.data_type != Internal.RegorusDataType.Pointer || result.pointer_value == null)
diff --git a/bindings/csharp/Regorus/Engine.cs b/bindings/csharp/Regorus/Engine.cs
index 2d8ed11..7b84e0b 100644
--- a/bindings/csharp/Regorus/Engine.cs
+++ b/bindings/csharp/Regorus/Engine.cs
@@ -373,21 +373,21 @@ namespace Regorus
 
         string? CheckAndDropResult(Regorus.Internal.RegorusResult result)
         {
-            if (result.status != Regorus.Internal.RegorusStatus.Ok)
+            try
             {
-                var message = StringFromUTF8((IntPtr)result.error_message);
-                var ex = new Exception(message);
-                Regorus.Internal.API.regorus_result_drop(result);
-                throw ex;
-            }
+                if (result.status != Regorus.Internal.RegorusStatus.Ok)
+                {
+                    var message = StringFromUTF8((IntPtr)result.error_message);
+                    throw result.status.CreateException(message);
+                }
 
-            var resultString = "";
-            if (result.output is not null)
-            {
-                resultString = StringFromUTF8((IntPtr)result.output);
+                var output = result.output is not null ? StringFromUTF8((IntPtr)result.output) : null;
+                return output ?? string.Empty;
+            }
+            finally
+            {
+                Regorus.Internal.API.regorus_result_drop(result);
             }
-            Regorus.Internal.API.regorus_result_drop(result);
-            return resultString;
         }
 
         private void ThrowIfDisposed()
diff --git a/bindings/csharp/Regorus/NativeMethods.cs b/bindings/csharp/Regorus/NativeMethods.cs
index a13bb77..f908740 100644
--- a/bindings/csharp/Regorus/NativeMethods.cs
+++ b/bindings/csharp/Regorus/NativeMethods.cs
@@ -217,6 +217,20 @@ namespace Regorus.Internal
         [DllImport(LibraryName, EntryPoint = "regorus_engine_compile_with_entrypoint", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
         internal static extern RegorusResult regorus_engine_compile_with_entrypoint(RegorusEngine* engine, byte* rule);
 
+    #if REGORUS_FFI_TEST_HOOKS
+        /// <summary>
+        /// Trigger a panic inside the engine for testing purposes.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_engine_test_trigger_panic", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_engine_test_trigger_panic();
+
+        /// <summary>
+        /// Reset the engine poison flag for testing.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_engine_test_reset_poison", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern void regorus_engine_test_reset_poison();
+    #endif
+
         #endregion
 
         #region Compilation Methods
@@ -472,6 +486,14 @@ namespace Regorus.Internal
         /// Invalid policy content.
         /// </summary>
         InvalidPolicy,
+        /// <summary>
+        /// The engine panicked and cannot be reused until reset.
+        /// </summary>
+        Panic,
+        /// <summary>
+        /// The engine remains poisoned because a previous panic was detected.
+        /// </summary>
+        Poisoned,
     }
 
     /// <summary>
diff --git a/bindings/csharp/Regorus/Regorus.csproj b/bindings/csharp/Regorus/Regorus.csproj
index e496497..621acdc 100644
--- a/bindings/csharp/Regorus/Regorus.csproj
+++ b/bindings/csharp/Regorus/Regorus.csproj
@@ -17,6 +17,10 @@
         <PackageReference Include="System.Text.Json" Version="8.0.5" />
     </ItemGroup>
 
+    <PropertyGroup Condition="'$(EnableRegorusTestHooks)' == 'true'">
+        <DefineConstants>$(DefineConstants);REGORUS_FFI_TEST_HOOKS</DefineConstants>
+    </PropertyGroup>
+
     <!--
         $(RegorusFFIArtifactsDir) is the location where regorus shared libraries have been
         built for various platforms and copied to. RegorusFFIArtifactsDir is passed in
diff --git a/bindings/csharp/Regorus/SchemaRegistry.cs b/bindings/csharp/Regorus/SchemaRegistry.cs
index 6ef8d87..54887e8 100644
--- a/bindings/csharp/Regorus/SchemaRegistry.cs
+++ b/bindings/csharp/Regorus/SchemaRegistry.cs
@@ -240,7 +240,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type switch
@@ -265,7 +265,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type == Internal.RegorusDataType.Boolean ? result.bool_value : false;
@@ -283,7 +283,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type == Internal.RegorusDataType.Integer ? result.int_value : 0;
diff --git a/bindings/csharp/Regorus/StatusExtensions.cs b/bindings/csharp/Regorus/StatusExtensions.cs
new file mode 100644
index 0000000..ff527c6
--- /dev/null
+++ b/bindings/csharp/Regorus/StatusExtensions.cs
@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+
+#nullable enable
+
+namespace Regorus.Internal
+{
+    internal static class StatusExtensions
+    {
+        internal static Exception CreateException(this RegorusStatus status, string? message)
+        {
+            var details = string.IsNullOrWhiteSpace(message) ? "Regorus call failed." : message;
+
+            return status switch
+            {
+                RegorusStatus.Panic => new InvalidOperationException($"Regorus engine panicked: {details}"),
+                RegorusStatus.Poisoned => new InvalidOperationException($"Regorus engine is poisoned: {details}"),
+                _ => new Exception(details),
+            };
+        }
+    }
+}
diff --git a/bindings/csharp/Regorus/TargetRegistry.cs b/bindings/csharp/Regorus/TargetRegistry.cs
index e2df083..6075e26 100644
--- a/bindings/csharp/Regorus/TargetRegistry.cs
+++ b/bindings/csharp/Regorus/TargetRegistry.cs
@@ -135,7 +135,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type switch
@@ -160,7 +160,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type == Internal.RegorusDataType.Boolean ? result.bool_value : false;
@@ -178,7 +178,7 @@ namespace Regorus
                 if (result.status != Internal.RegorusStatus.Ok)
                 {
                     var message = StringFromUTF8((IntPtr)result.error_message);
-                    throw new Exception(message ?? "Unknown error occurred");
+                    throw result.status.CreateException(message);
                 }
 
                 return result.data_type == Internal.RegorusDataType.Integer ? result.int_value : 0;
diff --git a/bindings/ffi/src/common.rs b/bindings/ffi/src/common.rs
index 2fe9b9a..11bc698 100644
--- a/bindings/ffi/src/common.rs
+++ b/bindings/ffi/src/common.rs
@@ -34,6 +34,12 @@ pub enum RegorusStatus {
 
     /// Invalid policy content.
     InvalidPolicy,
+
+    /// The engine panicked and cannot be reused until reset.
+    Panic,
+
+    /// The engine remains poisoned because a previous panic was detected.
+    Poisoned,
 }
 
 /// Type of data contained in RegorusResult
diff --git a/bindings/ffi/src/compile.rs b/bindings/ffi/src/compile.rs
index c175d00..ba1ee48 100644
--- a/bindings/ffi/src/compile.rs
+++ b/bindings/ffi/src/compile.rs
@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 use crate::common::{from_c_str, RegorusResult, RegorusStatus};
 use crate::compiled_policy::RegorusCompiledPolicy;
+use crate::panic_guard::with_unwind_guard;
 use alloc::boxed::Box;
 use alloc::format;
 use alloc::vec::Vec;
@@ -43,55 +44,54 @@ pub extern "C" fn regorus_compile_policy_with_entrypoint(
     modules_len: usize,
     entry_point_rule: *const c_char,
 ) -> RegorusResult {
-    let data_str = match from_c_str(data_json) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Invalid data JSON string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let data_str = match from_c_str(data_json) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Invalid data JSON string: {e}"),
+                )
+            }
+        };
 
-    let entry_rule = match from_c_str(entry_point_rule) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidEntrypoint,
-                format!("Invalid entry point rule string: {e}"),
-            )
-        }
-    };
+        let entry_rule = match from_c_str(entry_point_rule) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidEntrypoint,
+                    format!("Invalid entry point rule string: {e}"),
+                )
+            }
+        };
 
-    // Parse data JSON
-    let data = match Value::from_json_str(&data_str) {
-        Ok(data) => data,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Failed to parse data JSON: {e}"),
-            )
-        }
-    };
+        let data = match Value::from_json_str(&data_str) {
+            Ok(data) => data,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Failed to parse data JSON: {e}"),
+                )
+            }
+        };
 
-    // Convert C modules array to Rust Vec
-    let policy_modules = match convert_c_modules_to_rust(modules, modules_len) {
-        Ok(modules) => modules,
-        Err(status) => return RegorusResult::err(status),
-    };
+        let policy_modules = match convert_c_modules_to_rust(modules, modules_len) {
+            Ok(modules) => modules,
+            Err(status) => return RegorusResult::err(status),
+        };
 
-    // Call the convenience function
-    match compile_policy_with_entrypoint(data, &policy_modules, entry_rule.into()) {
-        Ok(compiled_policy) => {
-            let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
-            let boxed_policy = Box::new(wrapped_policy);
-            RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+        match compile_policy_with_entrypoint(data, &policy_modules, entry_rule.into()) {
+            Ok(compiled_policy) => {
+                let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
+                let boxed_policy = Box::new(wrapped_policy);
+                RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+            }
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::CompilationFailed,
+                format!("Policy compilation failed: {e}"),
+            ),
         }
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::CompilationFailed,
-            format!("Policy compilation failed: {e}"),
-        ),
-    }
+    })
 }
 
 /// Compiles a target-aware policy from data and modules.
@@ -122,45 +122,44 @@ pub extern "C" fn regorus_compile_policy_for_target(
     modules: *const RegorusPolicyModule,
     modules_len: usize,
 ) -> RegorusResult {
-    let data_str = match from_c_str(data_json) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Invalid data JSON string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let data_str = match from_c_str(data_json) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Invalid data JSON string: {e}"),
+                )
+            }
+        };
 
-    // Parse data JSON
-    let data = match Value::from_json_str(&data_str) {
-        Ok(data) => data,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Failed to parse data JSON: {e}"),
-            )
-        }
-    };
+        let data = match Value::from_json_str(&data_str) {
+            Ok(data) => data,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Failed to parse data JSON: {e}"),
+                )
+            }
+        };
 
-    // Convert C modules array to Rust Vec
-    let policy_modules = match convert_c_modules_to_rust(modules, modules_len) {
-        Ok(modules) => modules,
-        Err(status) => return RegorusResult::err(status),
-    };
+        let policy_modules = match convert_c_modules_to_rust(modules, modules_len) {
+            Ok(modules) => modules,
+            Err(status) => return RegorusResult::err(status),
+        };
 
-    // Call the convenience function
-    match compile_policy_for_target(data, &policy_modules) {
-        Ok(compiled_policy) => {
-            let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
-            let boxed_policy = Box::new(wrapped_policy);
-            RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+        match compile_policy_for_target(data, &policy_modules) {
+            Ok(compiled_policy) => {
+                let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
+                let boxed_policy = Box::new(wrapped_policy);
+                RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+            }
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::CompilationFailed,
+                format!("Target-aware policy compilation failed: {e}"),
+            ),
         }
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::CompilationFailed,
-            format!("Target-aware policy compilation failed: {e}"),
-        ),
-    }
+    })
 }
 
 /// Helper function to convert C module array to Rust Vec<PolicyModule>.
diff --git a/bindings/ffi/src/compiled_policy.rs b/bindings/ffi/src/compiled_policy.rs
index 8600535..005eb94 100644
--- a/bindings/ffi/src/compiled_policy.rs
+++ b/bindings/ffi/src/compiled_policy.rs
@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 use crate::common::*;
+use crate::panic_guard::with_unwind_guard;
 use alloc::boxed::Box;
 use alloc::string::String;
 use anyhow::Result;
@@ -35,18 +36,20 @@ pub extern "C" fn regorus_compiled_policy_eval_with_input(
     compiled_policy: *mut RegorusCompiledPolicy,
     input: *const c_char,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let input_value = regorus::Value::from_json_str(&from_c_str(input)?)?;
-        let result = to_ref(compiled_policy)?
-            .compiled_policy
-            .eval_with_input(input_value)?;
-        result.to_json_str()
-    }();
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let input_value = regorus::Value::from_json_str(&from_c_str(input)?)?;
+            let result = to_ref(compiled_policy)?
+                .compiled_policy
+                .eval_with_input(input_value)?;
+            result.to_json_str()
+        }();
 
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Get information about the compiled policy including metadata about modules,
@@ -59,14 +62,16 @@ pub extern "C" fn regorus_compiled_policy_eval_with_input(
 pub extern "C" fn regorus_compiled_policy_get_policy_info(
     compiled_policy: *mut RegorusCompiledPolicy,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let info = to_ref(compiled_policy)?.compiled_policy.get_policy_info()?;
-        serde_json::to_string(&info)
-            .map_err(|e| anyhow::anyhow!("Failed to serialize policy info: {}", e))
-    }();
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let info = to_ref(compiled_policy)?.compiled_policy.get_policy_info()?;
+            serde_json::to_string(&info)
+                .map_err(|e| anyhow::anyhow!("Failed to serialize policy info: {}", e))
+        }();
 
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
diff --git a/bindings/ffi/src/effect_registry.rs b/bindings/ffi/src/effect_registry.rs
index cdd348a..2e474e4 100644
--- a/bindings/ffi/src/effect_registry.rs
+++ b/bindings/ffi/src/effect_registry.rs
@@ -8,6 +8,7 @@
 
 #![cfg(feature = "azure_policy")]
 use crate::common::{from_c_str, RegorusResult, RegorusStatus};
+use crate::panic_guard::with_unwind_guard;
 use regorus::{registry::schemas, Schema};
 
 use std::os::raw::c_char;
@@ -29,45 +30,45 @@ pub extern "C" fn regorus_effect_schema_register(
     name: *const c_char,
     schema_json: *const c_char,
 ) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid effect schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid effect schema name string: {e}"),
+                )
+            }
+        };
 
-    let schema_str = match from_c_str(schema_json) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Invalid effect schema JSON string: {e}"),
-            )
-        }
-    };
+        let schema_str = match from_c_str(schema_json) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Invalid effect schema JSON string: {e}"),
+                )
+            }
+        };
 
-    // Parse schema from JSON
-    let schema = match Schema::from_json_str(&schema_str) {
-        Ok(schema) => schema,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Failed to parse effect schema JSON: {e}"),
-            )
-        }
-    };
+        let schema = match Schema::from_json_str(&schema_str) {
+            Ok(schema) => schema,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Failed to parse effect schema JSON: {e}"),
+                )
+            }
+        };
 
-    // Register the schema
-    match schemas::effect::register(schema_name, schema.into()) {
-        Ok(()) => RegorusResult::ok_pointer(std::ptr::null_mut()),
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::Error,
-            format!("Failed to register effect schema: {e}"),
-        ),
-    }
+        match schemas::effect::register(schema_name, schema.into()) {
+            Ok(()) => RegorusResult::ok_pointer(std::ptr::null_mut()),
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::Error,
+                format!("Failed to register effect schema: {e}"),
+            ),
+        }
+    })
 }
 
 /// Check if an effect schema with the given name exists.
@@ -83,18 +84,20 @@ pub extern "C" fn regorus_effect_schema_register(
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_contains(name: *const c_char) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid effect schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid effect schema name string: {e}"),
+                )
+            }
+        };
 
-    let contains = schemas::effect::contains(&schema_name);
-    RegorusResult::ok_bool(contains)
+        let contains = schemas::effect::contains(&schema_name);
+        RegorusResult::ok_bool(contains)
+    })
 }
 
 /// Get the number of registered effect schemas.
@@ -104,8 +107,10 @@ pub extern "C" fn regorus_effect_schema_contains(name: *const c_char) -> Regorus
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_len() -> RegorusResult {
-    let count = schemas::effect::len();
-    RegorusResult::ok_int(count as i64)
+    with_unwind_guard(|| {
+        let count = schemas::effect::len();
+        RegorusResult::ok_int(count as i64)
+    })
 }
 
 /// Check if the effect schema registry is empty.
@@ -115,8 +120,10 @@ pub extern "C" fn regorus_effect_schema_len() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_is_empty() -> RegorusResult {
-    let is_empty = schemas::effect::is_empty();
-    RegorusResult::ok_bool(is_empty)
+    with_unwind_guard(|| {
+        let is_empty = schemas::effect::is_empty();
+        RegorusResult::ok_bool(is_empty)
+    })
 }
 
 /// List all registered effect schema names as a JSON array.
@@ -126,14 +133,16 @@ pub extern "C" fn regorus_effect_schema_is_empty() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_list_names() -> RegorusResult {
-    let names = schemas::effect::list_names();
-    match serde_json::to_string(&names) {
-        Ok(json_str) => RegorusResult::ok_string(json_str),
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::Error,
-            format!("Failed to serialize effect schema names to JSON: {e}"),
-        ),
-    }
+    with_unwind_guard(|| {
+        let names = schemas::effect::list_names();
+        match serde_json::to_string(&names) {
+            Ok(json_str) => RegorusResult::ok_string(json_str),
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::Error,
+                format!("Failed to serialize effect schema names to JSON: {e}"),
+            ),
+        }
+    })
 }
 
 /// Remove an effect schema by name.
@@ -149,18 +158,20 @@ pub extern "C" fn regorus_effect_schema_list_names() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_remove(name: *const c_char) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid effect schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid effect schema name string: {e}"),
+                )
+            }
+        };
 
-    let removed = schemas::effect::remove(&schema_name).is_some();
-    RegorusResult::ok_bool(removed)
+        let removed = schemas::effect::remove(&schema_name).is_some();
+        RegorusResult::ok_bool(removed)
+    })
 }
 
 /// Clear all effect schemas from the registry.
@@ -170,6 +181,8 @@ pub extern "C" fn regorus_effect_schema_remove(name: *const c_char) -> RegorusRe
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_effect_schema_clear() -> RegorusResult {
-    schemas::effect::clear();
-    RegorusResult::ok_pointer(std::ptr::null_mut())
+    with_unwind_guard(|| {
+        schemas::effect::clear();
+        RegorusResult::ok_pointer(std::ptr::null_mut())
+    })
 }
diff --git a/bindings/ffi/src/engine.rs b/bindings/ffi/src/engine.rs
index 8fc09f7..cd6e9ea 100644
--- a/bindings/ffi/src/engine.rs
+++ b/bindings/ffi/src/engine.rs
@@ -6,6 +6,7 @@ use crate::common::{
 };
 use crate::compiled_policy::RegorusCompiledPolicy;
 use crate::lock::{new_handle, read, try_read, try_write, Handle, ReadGuard, WriteGuard};
+use crate::panic_guard::with_unwind_guard;
 use alloc::boxed::Box;
 use alloc::format;
 use alloc::string::String;
@@ -67,6 +68,101 @@ mod tests {
     }
 }
 
+#[cfg(all(test, feature = "std"))]
+mod panic_tests {
+    use super::{
+        regorus_engine_drop, regorus_engine_eval_query, regorus_engine_get_policies,
+        regorus_engine_new,
+    };
+    use crate::common::{regorus_result_drop, RegorusStatus};
+    use crate::panic_guard::{is_poisoned, reset_poison};
+    use alloc::boxed::Box;
+    use regorus::Value;
+    use std::ffi::{CStr, CString};
+
+    #[test]
+    fn catches_extension_panics_and_marks_poison() {
+        reset_poison();
+
+        let engine_ptr = regorus_engine_new();
+        assert!(!engine_ptr.is_null(), "engine allocation must succeed");
+        assert!(!is_poisoned(), "guard must start unpoisoned");
+
+        unsafe {
+            let engine = &mut *engine_ptr;
+            {
+                let mut guard = engine
+                    .try_write()
+                    .expect("exclusive access to configure engine");
+                guard
+                    .add_extension(
+                        "panic_extension".to_string(),
+                        0,
+                        Box::new(|_| -> anyhow::Result<Value> { panic!("ffi extension panic") }),
+                    )
+                    .expect("extension registration must succeed");
+                guard
+                    .add_policy(
+                        "panic.rego".to_string(),
+                        "package panic\n\ndefault allow = false\n\nallow if {\n  panic_extension()\n}"
+                            .to_string(),
+                    )
+                    .expect("policy registration must succeed");
+            }
+        }
+
+        let query = CString::new("data.panic.allow").expect("valid query string");
+        let panic_result = regorus_engine_eval_query(engine_ptr, query.as_ptr());
+        assert!(matches!(panic_result.status, RegorusStatus::Panic));
+        unsafe {
+            assert!(
+                !panic_result.error_message.is_null(),
+                "panic details must be present"
+            );
+            let message = CStr::from_ptr(panic_result.error_message)
+                .to_str()
+                .expect("error message utf8");
+            assert!(
+                message.contains("ffi extension panic"),
+                "panic payload must bubble across guard"
+            );
+        }
+        regorus_result_drop(panic_result);
+        assert!(is_poisoned(), "engine must be marked poisoned after panic");
+
+        let poisoned_result = regorus_engine_get_policies(engine_ptr);
+        assert!(matches!(poisoned_result.status, RegorusStatus::Poisoned));
+        unsafe {
+            assert!(
+                !poisoned_result.error_message.is_null(),
+                "poison message must be present"
+            );
+            let message = CStr::from_ptr(poisoned_result.error_message)
+                .to_str()
+                .expect("poison message utf8");
+            assert!(
+                message.contains("regorus is poisoned"),
+                "poison message must inform callers"
+            );
+        }
+        regorus_result_drop(poisoned_result);
+
+        regorus_engine_drop(engine_ptr);
+        reset_poison();
+    }
+}
+
+#[no_mangle]
+#[cfg(feature = "std")]
+pub extern "C" fn regorus_engine_test_trigger_panic() -> RegorusResult {
+    with_unwind_guard(|| panic!("regorus ffi test panic"))
+}
+
+#[no_mangle]
+pub extern "C" fn regorus_engine_test_reset_poison() {
+    crate::panic_guard::reset_poison();
+}
+
 #[no_mangle]
 /// Construct a new Engine
 ///
@@ -116,11 +212,13 @@ pub extern "C" fn regorus_engine_add_policy(
     path: *const c_char,
     rego: *const c_char,
 ) -> RegorusResult {
-    to_regorus_string_result(|| -> Result<String> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.add_policy(from_c_str(path)?, from_c_str(rego)?)
-    }())
+    with_unwind_guard(|| {
+        to_regorus_string_result(|| -> Result<String> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.add_policy(from_c_str(path)?, from_c_str(rego)?)
+        }())
+    })
 }
 
 #[cfg(feature = "std")]
@@ -129,11 +227,13 @@ pub extern "C" fn regorus_engine_add_policy_from_file(
     engine: *mut RegorusEngine,
     path: *const c_char,
 ) -> RegorusResult {
-    to_regorus_string_result(|| -> Result<String> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.add_policy_from_file(from_c_str(path)?)
-    }())
+    with_unwind_guard(|| {
+        to_regorus_string_result(|| -> Result<String> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.add_policy_from_file(from_c_str(path)?)
+        }())
+    })
 }
 
 /// Add policy data.
@@ -145,11 +245,13 @@ pub extern "C" fn regorus_engine_add_data_json(
     engine: *mut RegorusEngine,
     data: *const c_char,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.add_data(regorus::Value::from_json_str(&from_c_str(data)?)?)
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.add_data(regorus::Value::from_json_str(&from_c_str(data)?)?)
+        }())
+    })
 }
 
 /// Get list of loaded Rego packages as JSON.
@@ -157,11 +259,13 @@ pub extern "C" fn regorus_engine_add_data_json(
 /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.get_packages
 #[no_mangle]
 pub extern "C" fn regorus_engine_get_packages(engine: *mut RegorusEngine) -> RegorusResult {
-    to_regorus_string_result(|| -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        serde_json::to_string_pretty(&guard.get_packages()?).map_err(anyhow::Error::msg)
-    }())
+    with_unwind_guard(|| {
+        to_regorus_string_result(|| -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            serde_json::to_string_pretty(&guard.get_packages()?).map_err(anyhow::Error::msg)
+        }())
+    })
 }
 
 /// Get list of policies as JSON.
@@ -169,11 +273,13 @@ pub extern "C" fn regorus_engine_get_packages(engine: *mut RegorusEngine) -> Reg
 /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.get_policies
 #[no_mangle]
 pub extern "C" fn regorus_engine_get_policies(engine: *mut RegorusEngine) -> RegorusResult {
-    to_regorus_string_result(|| -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        guard.get_policies_as_json()
-    }())
+    with_unwind_guard(|| {
+        to_regorus_string_result(|| -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            guard.get_policies_as_json()
+        }())
+    })
 }
 
 #[cfg(feature = "std")]
@@ -182,11 +288,13 @@ pub extern "C" fn regorus_engine_add_data_from_json_file(
     engine: *mut RegorusEngine,
     path: *const c_char,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.add_data(regorus::Value::from_json_file(from_c_str(path)?)?)
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.add_data(regorus::Value::from_json_file(from_c_str(path)?)?)
+        }())
+    })
 }
 
 /// Clear policy data.
@@ -194,12 +302,14 @@ pub extern "C" fn regorus_engine_add_data_from_json_file(
 /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.clear_data
 #[no_mangle]
 pub extern "C" fn regorus_engine_clear_data(engine: *mut RegorusEngine) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.clear_data();
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.clear_data();
+            Ok(())
+        }())
+    })
 }
 
 /// Set input.
@@ -211,12 +321,14 @@ pub extern "C" fn regorus_engine_set_input_json(
     engine: *mut RegorusEngine,
     input: *const c_char,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_input(regorus::Value::from_json_str(&from_c_str(input)?)?);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_input(regorus::Value::from_json_str(&from_c_str(input)?)?);
+            Ok(())
+        }())
+    })
 }
 
 #[cfg(feature = "std")]
@@ -225,12 +337,14 @@ pub extern "C" fn regorus_engine_set_input_from_json_file(
     engine: *mut RegorusEngine,
     path: *const c_char,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_input(regorus::Value::from_json_file(from_c_str(path)?)?);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_input(regorus::Value::from_json_file(from_c_str(path)?)?);
+            Ok(())
+        }())
+    })
 }
 
 /// Evaluate query.
@@ -242,16 +356,18 @@ pub extern "C" fn regorus_engine_eval_query(
     engine: *mut RegorusEngine,
     query: *const c_char,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        let results = guard.eval_query(from_c_str(query)?, false)?;
-        Ok(serde_json::to_string_pretty(&results)?)
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            let results = guard.eval_query(from_c_str(query)?, false)?;
+            Ok(serde_json::to_string_pretty(&results)?)
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Evaluate specified rule.
@@ -263,15 +379,17 @@ pub extern "C" fn regorus_engine_eval_rule(
     engine: *mut RegorusEngine,
     rule: *const c_char,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.eval_rule(from_c_str(rule)?)?.to_json_str()
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.eval_rule(from_c_str(rule)?)?.to_json_str()
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Enable/disable coverage.
@@ -284,12 +402,14 @@ pub extern "C" fn regorus_engine_set_enable_coverage(
     engine: *mut RegorusEngine,
     enable: bool,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_enable_coverage(enable);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_enable_coverage(enable);
+            Ok(())
+        }())
+    })
 }
 
 /// Get coverage report.
@@ -298,15 +418,17 @@ pub extern "C" fn regorus_engine_set_enable_coverage(
 #[no_mangle]
 #[cfg(feature = "coverage")]
 pub extern "C" fn regorus_engine_get_coverage_report(engine: *mut RegorusEngine) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        Ok(serde_json::to_string_pretty(&guard.get_coverage_report()?)?)
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            Ok(serde_json::to_string_pretty(&guard.get_coverage_report()?)?)
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Enable/disable strict builtin errors.
@@ -318,12 +440,14 @@ pub extern "C" fn regorus_engine_set_strict_builtin_errors(
     engine: *mut RegorusEngine,
     strict: bool,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_strict_builtin_errors(strict);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_strict_builtin_errors(strict);
+            Ok(())
+        }())
+    })
 }
 
 /// Get pretty printed coverage report.
@@ -334,15 +458,17 @@ pub extern "C" fn regorus_engine_set_strict_builtin_errors(
 pub extern "C" fn regorus_engine_get_coverage_report_pretty(
     engine: *mut RegorusEngine,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        guard.get_coverage_report()?.to_string_pretty()
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            guard.get_coverage_report()?.to_string_pretty()
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Clear coverage data.
@@ -351,12 +477,14 @@ pub extern "C" fn regorus_engine_get_coverage_report_pretty(
 #[no_mangle]
 #[cfg(feature = "coverage")]
 pub extern "C" fn regorus_engine_clear_coverage_data(engine: *mut RegorusEngine) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.clear_coverage_data();
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.clear_coverage_data();
+            Ok(())
+        }())
+    })
 }
 
 /// Whether to gather output of print statements.
@@ -368,12 +496,14 @@ pub extern "C" fn regorus_engine_set_gather_prints(
     engine: *mut RegorusEngine,
     enable: bool,
 ) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_gather_prints(enable);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_gather_prints(enable);
+            Ok(())
+        }())
+    })
 }
 
 /// Take all the gathered print statements.
@@ -381,15 +511,17 @@ pub extern "C" fn regorus_engine_set_gather_prints(
 /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.take_prints
 #[no_mangle]
 pub extern "C" fn regorus_engine_take_prints(engine: *mut RegorusEngine) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        Ok(serde_json::to_string_pretty(&guard.take_prints()?)?)
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            Ok(serde_json::to_string_pretty(&guard.take_prints()?)?)
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Get AST of policies.
@@ -398,15 +530,17 @@ pub extern "C" fn regorus_engine_take_prints(engine: *mut RegorusEngine) -> Rego
 #[no_mangle]
 #[cfg(feature = "ast")]
 pub extern "C" fn regorus_engine_get_ast_as_json(engine: *mut RegorusEngine) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        guard.get_ast_as_json()
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            guard.get_ast_as_json()
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Gets the package names defined in each policy added to the engine.
@@ -417,15 +551,18 @@ pub extern "C" fn regorus_engine_get_ast_as_json(engine: *mut RegorusEngine) ->
 pub extern "C" fn regorus_engine_get_policy_package_names(
     engine: *mut RegorusEngine,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        serde_json::to_string_pretty(&guard.get_policy_package_names()?).map_err(anyhow::Error::msg)
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            serde_json::to_string_pretty(&guard.get_policy_package_names()?)
+                .map_err(anyhow::Error::msg)
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Gets the parameters defined in each policy added to the engine.
@@ -436,15 +573,18 @@ pub extern "C" fn regorus_engine_get_policy_package_names(
 pub extern "C" fn regorus_engine_get_policy_parameters(
     engine: *mut RegorusEngine,
 ) -> RegorusResult {
-    let output = || -> Result<String> {
-        let engine = to_ref(engine)?;
-        let guard = engine.try_read()?;
-        serde_json::to_string_pretty(&guard.get_policy_parameters()?).map_err(anyhow::Error::msg)
-    }();
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<String> {
+            let engine = to_ref(engine)?;
+            let guard = engine.try_read()?;
+            serde_json::to_string_pretty(&guard.get_policy_parameters()?)
+                .map_err(anyhow::Error::msg)
+        }();
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Enable/disable rego v1.
@@ -455,16 +595,18 @@ pub extern "C" fn regorus_engine_set_rego_v0(
     engine: *mut RegorusEngine,
     enable: bool,
 ) -> RegorusResult {
-    let output = || -> Result<()> {
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        guard.set_rego_v0(enable);
-        Ok(())
-    }();
-    match output {
-        Ok(()) => RegorusResult::ok_void(),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+    with_unwind_guard(|| {
+        let output = || -> Result<()> {
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            guard.set_rego_v0(enable);
+            Ok(())
+        }();
+        match output {
+            Ok(()) => RegorusResult::ok_void(),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Compile a target-aware policy from the current engine state.
@@ -476,37 +618,39 @@ pub extern "C" fn regorus_engine_set_rego_v0(
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_engine_compile_for_target(engine: *mut RegorusEngine) -> RegorusResult {
-    let engine = match to_ref(engine) {
-        Ok(engine) => engine,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Failed to get engine reference: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let engine = match to_ref(engine) {
+            Ok(engine) => engine,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Failed to get engine reference: {e}"),
+                )
+            }
+        };
 
-    let mut guard = match engine.try_write() {
-        Ok(guard) => guard,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::Error,
-                format!("Failed to lock engine: {e}"),
-            )
-        }
-    };
+        let mut guard = match engine.try_write() {
+            Ok(guard) => guard,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::Error,
+                    format!("Failed to lock engine: {e}"),
+                )
+            }
+        };
 
-    match guard.compile_for_target() {
-        Ok(compiled_policy) => {
-            let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
-            let boxed_policy = Box::new(wrapped_policy);
-            RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+        match guard.compile_for_target() {
+            Ok(compiled_policy) => {
+                let wrapped_policy = RegorusCompiledPolicy { compiled_policy };
+                let boxed_policy = Box::new(wrapped_policy);
+                RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+            }
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::CompilationFailed,
+                format!("Failed to compile for target: {e}"),
+            ),
         }
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::CompilationFailed,
-            format!("Failed to compile for target: {e}"),
-        ),
-    }
+    })
 }
 
 /// Compile a policy with a specific entry point rule.
@@ -520,23 +664,25 @@ pub extern "C" fn regorus_engine_compile_with_entrypoint(
     engine: *mut RegorusEngine,
     rule: *const c_char,
 ) -> RegorusResult {
-    let result = || -> Result<RegorusCompiledPolicy> {
-        let rule_str = from_c_str(rule)?;
-        let rule_rc: regorus::Rc<str> = rule_str.into();
-        let engine = to_ref(engine)?;
-        let mut guard = engine.try_write()?;
-        let compiled_policy = guard.compile_with_entrypoint(&rule_rc)?;
-        Ok(RegorusCompiledPolicy { compiled_policy })
-    }();
+    with_unwind_guard(|| {
+        let result = || -> Result<RegorusCompiledPolicy> {
+            let rule_str = from_c_str(rule)?;
+            let rule_rc: regorus::Rc<str> = rule_str.into();
+            let engine = to_ref(engine)?;
+            let mut guard = engine.try_write()?;
+            let compiled_policy = guard.compile_with_entrypoint(&rule_rc)?;
+            Ok(RegorusCompiledPolicy { compiled_policy })
+        }();
 
-    match result {
-        Ok(wrapped_policy) => {
-            let boxed_policy = Box::new(wrapped_policy);
-            RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+        match result {
+            Ok(wrapped_policy) => {
+                let boxed_policy = Box::new(wrapped_policy);
+                RegorusResult::ok_pointer(Box::into_raw(boxed_policy) as *mut c_void)
+            }
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::CompilationFailed,
+                format!("Failed to compile with entrypoint: {e}"),
+            ),
         }
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::CompilationFailed,
-            format!("Failed to compile with entrypoint: {e}"),
-        ),
-    }
+    })
 }
diff --git a/bindings/ffi/src/lib.rs b/bindings/ffi/src/lib.rs
index 0b4eb82..3f8585e 100644
--- a/bindings/ffi/src/lib.rs
+++ b/bindings/ffi/src/lib.rs
@@ -12,5 +12,6 @@ mod compiled_policy;
 mod effect_registry;
 mod engine;
 mod lock;
+mod panic_guard;
 mod schema_registry;
 mod target_registry;
diff --git a/bindings/ffi/src/panic_guard.rs b/bindings/ffi/src/panic_guard.rs
new file mode 100644
index 0000000..0293e8f
--- /dev/null
+++ b/bindings/ffi/src/panic_guard.rs
@@ -0,0 +1,159 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+//! Minimal helpers for catching panics inside the FFI layer.
+//!
+//! These are not yet wired into the exported functions; they will
+//! be used once the integration work is complete.
+
+extern crate alloc;
+
+use crate::common::{RegorusResult, RegorusStatus};
+
+use alloc::string::String;
+use core::sync::atomic::{AtomicBool, Ordering};
+#[cfg(feature = "std")]
+use std::{
+    backtrace::Backtrace,
+    cell::RefCell,
+    panic::{self, AssertUnwindSafe},
+};
+
+#[cfg(feature = "std")]
+thread_local! {
+    // Stashes the formatted panic + backtrace for whichever call last panicked on this thread.
+    static PANIC_BACKTRACE: RefCell<Option<String>> = const { RefCell::new(None) };
+}
+
+#[cfg(feature = "std")]
+type PanicHook = dyn Fn(&panic::PanicHookInfo<'_>) + Sync + Send + 'static;
+
+#[cfg(feature = "std")]
+/// RAII helper that installs a per-call panic hook and restores the prior hook on drop.
+struct PanicHookGuard {
+    previous: Option<Box<PanicHook>>,
+}
+
+#[cfg(feature = "std")]
+impl PanicHookGuard {
+    fn install() -> Self {
+        // Remember whatever hook the embedding application already registered.
+        let previous = panic::take_hook();
+        PANIC_BACKTRACE.with(|slot| {
+            slot.replace(None);
+        });
+        // Install our temporary hook so we can capture a backtrace for this invocation.
+        panic::set_hook(Box::new(|info| {
+            let backtrace = Backtrace::force_capture();
+            PANIC_BACKTRACE.with(|slot| {
+                slot.replace(Some(format!(
+                    "panic hook observed: {}\nbacktrace:\n{:#?}",
+                    info, backtrace
+                )));
+            });
+        }));
+        Self {
+            previous: Some(previous),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl Drop for PanicHookGuard {
+    fn drop(&mut self) {
+        if let Some(previous) = self.previous.take() {
+            // Restore the original panic hook before we return control to the host.
+            panic::set_hook(previous);
+        }
+    }
+}
+
+static POISONED: AtomicBool = AtomicBool::new(false);
+
+/// Result of attempting to run `f` while guarding against unwinding.
+pub(crate) enum GuardResult<T> {
+    /// Closure completed successfully.
+    Success(T),
+    /// Closure panicked; contains a best-effort string payload.
+    Panic(String),
+}
+
+pub(crate) fn with_unwind_guard<F>(f: F) -> RegorusResult
+where
+    F: FnOnce() -> RegorusResult,
+{
+    if is_poisoned() {
+        return poisoned_result();
+    }
+
+    // The closure passed across this boundary closes over raw pointers and lock guards.
+    // These types are not unwind safe by default and may become poisoned if a panic occurs.
+    // We therefore use AssertUnwindSafe to get the compiler to accept the closure.
+    // Upon unwind, we mark regorus as poisoned and disallow further use.
+    #[cfg(feature = "std")]
+    {
+        let outcome = {
+            let _hook_guard = PanicHookGuard::install();
+            match panic::catch_unwind(AssertUnwindSafe(f)) {
+                Ok(value) => GuardResult::Success(value),
+                Err(payload) => GuardResult::Panic(panic_message_to_string(payload)),
+            }
+        };
+        finalize(outcome)
+    }
+
+    #[cfg(not(feature = "std"))]
+    return finalize(GuardResult::Success(f()));
+}
+
+fn finalize(outcome: GuardResult<RegorusResult>) -> RegorusResult {
+    match outcome {
+        GuardResult::Success(result) => result,
+        GuardResult::Panic(message) => {
+            trip_poison();
+            RegorusResult::err_with_message(RegorusStatus::Panic, message)
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+fn panic_message_to_string(payload: Box<dyn core::any::Any + Send + 'static>) -> String {
+    let mut message = if let Some(s) = payload.downcast_ref::<&str>() {
+        (*s).into()
+    } else if let Some(s) = payload.downcast_ref::<String>() {
+        s.clone()
+    } else {
+        String::from("regorus encountered panic")
+    };
+
+    if let Some(backtrace) = take_panic_backtrace() {
+        message.push('\n');
+        message.push_str(&backtrace);
+    }
+
+    message
+}
+
+#[cfg(feature = "std")]
+fn take_panic_backtrace() -> Option<String> {
+    PANIC_BACKTRACE.with(|slot| slot.borrow_mut().take())
+}
+
+fn poisoned_result() -> RegorusResult {
+    RegorusResult::err_with_message(
+        RegorusStatus::Poisoned,
+        String::from("regorus is poisoned after a previous panic"),
+    )
+}
+
+fn trip_poison() {
+    POISONED.store(true, Ordering::Release);
+}
+
+pub(crate) fn is_poisoned() -> bool {
+    POISONED.load(Ordering::Acquire)
+}
+
+pub(crate) fn reset_poison() {
+    POISONED.store(false, Ordering::Release);
+}
diff --git a/bindings/ffi/src/schema_registry.rs b/bindings/ffi/src/schema_registry.rs
index a7bf50c..bab80e2 100644
--- a/bindings/ffi/src/schema_registry.rs
+++ b/bindings/ffi/src/schema_registry.rs
@@ -9,6 +9,7 @@
 #![cfg(feature = "azure_policy")]
 
 use crate::common::{from_c_str, RegorusResult, RegorusStatus};
+use crate::panic_guard::with_unwind_guard;
 use regorus::{registry::schemas, Schema};
 
 use std::os::raw::c_char;
@@ -32,45 +33,45 @@ pub extern "C" fn regorus_resource_schema_register(
     name: *const c_char,
     schema_json: *const c_char,
 ) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid schema name string: {e}"),
+                )
+            }
+        };
 
-    let schema_str = match from_c_str(schema_json) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Invalid schema JSON string: {e}"),
-            )
-        }
-    };
+        let schema_str = match from_c_str(schema_json) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Invalid schema JSON string: {e}"),
+                )
+            }
+        };
 
-    // Parse schema from JSON
-    let schema = match Schema::from_json_str(&schema_str) {
-        Ok(schema) => schema,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidDataFormat,
-                format!("Failed to parse schema JSON: {e}"),
-            )
-        }
-    };
+        let schema = match Schema::from_json_str(&schema_str) {
+            Ok(schema) => schema,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidDataFormat,
+                    format!("Failed to parse schema JSON: {e}"),
+                )
+            }
+        };
 
-    // Register the schema
-    match schemas::resource::register(schema_name, schema.into()) {
-        Ok(()) => RegorusResult::ok_pointer(std::ptr::null_mut()),
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::Error,
-            format!("Failed to register schema: {e}"),
-        ),
-    }
+        match schemas::resource::register(schema_name, schema.into()) {
+            Ok(()) => RegorusResult::ok_pointer(std::ptr::null_mut()),
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::Error,
+                format!("Failed to register schema: {e}"),
+            ),
+        }
+    })
 }
 
 /// Check if a resource schema with the given name exists.
@@ -86,18 +87,20 @@ pub extern "C" fn regorus_resource_schema_register(
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_contains(name: *const c_char) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid schema name string: {e}"),
+                )
+            }
+        };
 
-    let contains = schemas::resource::contains(&schema_name);
-    RegorusResult::ok_bool(contains)
+        let contains = schemas::resource::contains(&schema_name);
+        RegorusResult::ok_bool(contains)
+    })
 }
 
 /// Get the number of registered resource schemas.
@@ -107,8 +110,10 @@ pub extern "C" fn regorus_resource_schema_contains(name: *const c_char) -> Regor
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_len() -> RegorusResult {
-    let count = schemas::resource::len();
-    RegorusResult::ok_int(count as i64)
+    with_unwind_guard(|| {
+        let count = schemas::resource::len();
+        RegorusResult::ok_int(count as i64)
+    })
 }
 
 /// Check if the resource schema registry is empty.
@@ -118,8 +123,10 @@ pub extern "C" fn regorus_resource_schema_len() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_is_empty() -> RegorusResult {
-    let is_empty = schemas::resource::is_empty();
-    RegorusResult::ok_bool(is_empty)
+    with_unwind_guard(|| {
+        let is_empty = schemas::resource::is_empty();
+        RegorusResult::ok_bool(is_empty)
+    })
 }
 
 /// List all registered resource schema names as a JSON array.
@@ -129,14 +136,16 @@ pub extern "C" fn regorus_resource_schema_is_empty() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_list_names() -> RegorusResult {
-    let names = schemas::resource::list_names();
-    match serde_json::to_string(&names) {
-        Ok(json_str) => RegorusResult::ok_string(json_str),
-        Err(e) => RegorusResult::err_with_message(
-            RegorusStatus::Error,
-            format!("Failed to serialize schema names to JSON: {e}"),
-        ),
-    }
+    with_unwind_guard(|| {
+        let names = schemas::resource::list_names();
+        match serde_json::to_string(&names) {
+            Ok(json_str) => RegorusResult::ok_string(json_str),
+            Err(e) => RegorusResult::err_with_message(
+                RegorusStatus::Error,
+                format!("Failed to serialize schema names to JSON: {e}"),
+            ),
+        }
+    })
 }
 
 /// Remove a resource schema by name.
@@ -152,18 +161,20 @@ pub extern "C" fn regorus_resource_schema_list_names() -> RegorusResult {
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_remove(name: *const c_char) -> RegorusResult {
-    let schema_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid schema name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let schema_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid schema name string: {e}"),
+                )
+            }
+        };
 
-    let removed = schemas::resource::remove(&schema_name).is_some();
-    RegorusResult::ok_bool(removed)
+        let removed = schemas::resource::remove(&schema_name).is_some();
+        RegorusResult::ok_bool(removed)
+    })
 }
 
 /// Clear all resource schemas from the registry.
@@ -173,6 +184,8 @@ pub extern "C" fn regorus_resource_schema_remove(name: *const c_char) -> Regorus
 #[cfg(feature = "azure_policy")]
 #[no_mangle]
 pub extern "C" fn regorus_resource_schema_clear() -> RegorusResult {
-    schemas::resource::clear();
-    RegorusResult::ok_pointer(std::ptr::null_mut())
+    with_unwind_guard(|| {
+        schemas::resource::clear();
+        RegorusResult::ok_pointer(std::ptr::null_mut())
+    })
 }
diff --git a/bindings/ffi/src/target_registry.rs b/bindings/ffi/src/target_registry.rs
index 8ca2a44..7b3f63a 100644
--- a/bindings/ffi/src/target_registry.rs
+++ b/bindings/ffi/src/target_registry.rs
@@ -4,6 +4,7 @@
 #![cfg(feature = "azure_policy")]
 
 use crate::common::*;
+use crate::panic_guard::with_unwind_guard;
 use anyhow::Result;
 use std::os::raw::c_char;
 
@@ -16,12 +17,14 @@ use std::os::raw::c_char;
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_register_target_from_json(target_json: *const c_char) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let target_str = from_c_str(target_json)?;
-        let target = regorus::Target::from_json_str(&target_str)?;
-        regorus::registry::targets::register(regorus::Rc::new(target))?;
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let target_str = from_c_str(target_json)?;
+            let target = regorus::Target::from_json_str(&target_str)?;
+            regorus::registry::targets::register(regorus::Rc::new(target))?;
+            Ok(())
+        }())
+    })
 }
 
 /// Check if a target is registered.
@@ -36,31 +39,35 @@ pub extern "C" fn regorus_register_target_from_json(target_json: *const c_char)
 /// The name parameter must be a valid null-terminated UTF-8 string.
 #[no_mangle]
 pub extern "C" fn regorus_target_registry_contains(name: *const c_char) -> RegorusResult {
-    let target_name = match from_c_str(name) {
-        Ok(s) => s,
-        Err(e) => {
-            return RegorusResult::err_with_message(
-                RegorusStatus::InvalidArgument,
-                format!("Invalid target name string: {e}"),
-            )
-        }
-    };
+    with_unwind_guard(|| {
+        let target_name = match from_c_str(name) {
+            Ok(s) => s,
+            Err(e) => {
+                return RegorusResult::err_with_message(
+                    RegorusStatus::InvalidArgument,
+                    format!("Invalid target name string: {e}"),
+                )
+            }
+        };
 
-    let contains = regorus::registry::targets::contains(&target_name);
-    RegorusResult::ok_bool(contains)
+        let contains = regorus::registry::targets::contains(&target_name);
+        RegorusResult::ok_bool(contains)
+    })
 }
 
 /// Get a list of all registered target names as JSON array.
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_target_registry_list_names() -> RegorusResult {
-    let names = regorus::registry::targets::list_names();
-    let output = serde_json::to_string_pretty(&names).map_err(anyhow::Error::msg);
+    with_unwind_guard(|| {
+        let names = regorus::registry::targets::list_names();
+        let output = serde_json::to_string_pretty(&names).map_err(anyhow::Error::msg);
 
-    match output {
-        Ok(out) => RegorusResult::ok_string(out),
-        Err(e) => to_regorus_result(Err(e)),
-    }
+        match output {
+            Ok(out) => RegorusResult::ok_string(out),
+            Err(e) => to_regorus_result(Err(e)),
+        }
+    })
 }
 
 /// Remove a target from the registry by name.
@@ -69,19 +76,23 @@ pub extern "C" fn regorus_target_registry_list_names() -> RegorusResult {
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_target_registry_remove(name: *const c_char) -> RegorusResult {
-    to_regorus_result(|| -> Result<()> {
-        let name_str = from_c_str(name)?;
-        regorus::registry::targets::remove(&name_str);
-        Ok(())
-    }())
+    with_unwind_guard(|| {
+        to_regorus_result(|| -> Result<()> {
+            let name_str = from_c_str(name)?;
+            regorus::registry::targets::remove(&name_str);
+            Ok(())
+        }())
+    })
 }
 
 /// Clear all targets from the registry.
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_target_registry_clear() -> RegorusResult {
-    regorus::registry::targets::clear();
-    RegorusResult::ok_void()
+    with_unwind_guard(|| {
+        regorus::registry::targets::clear();
+        RegorusResult::ok_void()
+    })
 }
 
 /// Get the number of registered targets.
@@ -91,8 +102,10 @@ pub extern "C" fn regorus_target_registry_clear() -> RegorusResult {
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_target_registry_len() -> RegorusResult {
-    let count = regorus::registry::targets::len();
-    RegorusResult::ok_int(count as i64)
+    with_unwind_guard(|| {
+        let count = regorus::registry::targets::len();
+        RegorusResult::ok_int(count as i64)
+    })
 }
 
 /// Check if the target registry is empty.
@@ -102,6 +115,8 @@ pub extern "C" fn regorus_target_registry_len() -> RegorusResult {
 #[no_mangle]
 #[cfg(feature = "azure_policy")]
 pub extern "C" fn regorus_target_registry_is_empty() -> RegorusResult {
-    let is_empty = regorus::registry::targets::is_empty();
-    RegorusResult::ok_bool(is_empty)
+    with_unwind_guard(|| {
+        let is_empty = regorus::registry::targets::is_empty();
+        RegorusResult::ok_bool(is_empty)
+    })
 }