AI Agent Safety for C# and .NET Developers

SafeClaw by Authensor brings deny-by-default action gating to C# and .NET AI agents, including those built with Microsoft Semantic Kernel. Every Process.Start(), File.ReadAllText(), and HttpClient.SendAsync() call is gated against your YAML policy before execution. Install SafeClaw with npx @authensor/safeclaw and integrate it into your .NET agent via the local REST API.

.NET Agent Risk Surface

.NET AI agents — especially those using Semantic Kernel's auto function calling — can invoke dangerous system APIs:

• System.Diagnostics.Process.Start() — execute arbitrary commands
• System.IO.File — read, write, delete files
• System.Net.Http.HttpClient — make outbound network requests
• System.Environment.GetEnvironmentVariable() — access secrets

Installation

npx @authensor/safeclaw

Policy

version: 1
defaultAction: deny

rules:
  - action: file.read
    path:
      glob: "C:\\App\\Data\\**"
    decision: allow

- action: file.write
    path:
      glob: "C:\\App\\Output\\**"
    decision: allow

- action: process.exec
    command:
      startsWith: "dotnet"
    decision: allow

- action: network.request
    host:
      in: ["api.openai.com", "api.anthropic.com"]
    decision: allow

- action: file.read
    path:
      glob: "*\\appsettings.json"
    decision: deny

C# Integration

using System.Net.Http.Json;
using System.Text.Json.Serialization;

public record ActionRequest(
    [property: JsonPropertyName("action")] string Action,
    [property: JsonPropertyName("path")] string? Path = null,
    [property: JsonPropertyName("command")] string? Command = null,
    [property: JsonPropertyName("host")] string? Host = null,
    [property: JsonPropertyName("url")] string? Url = null,
    [property: JsonPropertyName("method")] string? Method = null
);

public record GateDecision(
    [property: JsonPropertyName("allowed")] bool Allowed,
    [property: JsonPropertyName("reason")] string Reason
);

public class SafeClawGate : IDisposable
{
    private readonly HttpClient _client = new();
    private readonly string _endpoint;

public SafeClawGate(string endpoint = "http://localhost:9800")
    {
        _endpoint = endpoint;
    }

public async Task<GateDecision> CheckAsync(ActionRequest request)
    {
        try
        {
            var response = await _client.PostAsJsonAsync($"{_endpoint}/check", request);
            response.EnsureSuccessStatusCode();
            return await response.Content.ReadFromJsonAsync<GateDecision>()
                ?? new GateDecision(false, "Deserialization failed");
        }
        catch
        {
            // Fail closed
            return new GateDecision(false, "SafeClaw unreachable");
        }
    }

public void Dispose() => _client.Dispose();
}

Semantic Kernel Integration

Wrap Semantic Kernel native functions with SafeClaw gating:

using Microsoft.SemanticKernel;
using System.ComponentModel;
using System.Diagnostics;

public class SafeFilePlugin
{
    private readonly SafeClawGate _gate = new();

[KernelFunction, Description("Read a file from disk")]
    public async Task<string> ReadFileAsync(string path)
    {
        var decision = await _gate.CheckAsync(new ActionRequest("file.read", Path: path));
        if (!decision.Allowed)
            throw new UnauthorizedAccessException($"SafeClaw denied: {decision.Reason}");

return await File.ReadAllTextAsync(path);
    }

[KernelFunction, Description("Execute a shell command")]
    public async Task<string> ExecCommandAsync(string command)
    {
        var decision = await _gate.CheckAsync(new ActionRequest("process.exec", Command: command));
        if (!decision.Allowed)
            throw new UnauthorizedAccessException($"SafeClaw denied: {decision.Reason}");

var process = Process.Start(new ProcessStartInfo
        {
            FileName = "cmd.exe",
            Arguments = $"/c {command}",
            RedirectStandardOutput = true,
            UseShellExecute = false
        });
        return await process!.StandardOutput.ReadToEndAsync();
    }
}

Register with the kernel:

var kernel = Kernel.CreateBuilder()
    .AddOpenAIChatCompletion("gpt-4", apiKey)
    .Build();

kernel.Plugins.AddFromObject(new SafeFilePlugin());

SafeClaw logs all decisions to its hash-chained audit trail. MIT licensed, provider-agnostic.

Cross-References

• Semantic Kernel Framework Guide
• Deny-by-Default Explained
• Docker Compose Deployment
• Enterprise Compliance Reporting