1 files changed, 31 insertions, 0 deletions
diff --git a/src/Agent.Core/Tools/ToolPolicy.cs b/src/Agent.Core/Tools/ToolPolicy.cs
new file mode 100644
index 0000000..c9f216a
--- /dev/null
+++ b/src/Agent.Core/Tools/ToolPolicy.cs
@@ -0,0 +1,31 @@
+using System.Text.Json;
+
+namespace Agent.Core.Tools;
+
+public sealed record ToolPolicyDecision(bool Allowed, string Reason)
+{
+    public static ToolPolicyDecision Allow() => new(true, "allowed");
+    public static ToolPolicyDecision Deny(string reason) => new(false, reason);
+}
+
+public interface IToolPolicyEngine
+{
+    ToolPolicyDecision Evaluate(string toolName, JsonElement arguments);
+}
+
+public interface IInternalToolBackend
+{
+    Task BeginTaskAsync(Guid taskId, CancellationToken cancellationToken) => Task.CompletedTask;
+    Task<ToolExecutionResult> ExecuteAsync(Guid taskId, string toolName, JsonElement arguments, CancellationToken cancellationToken);
+    Task EndTaskAsync(Guid taskId, bool success, CancellationToken cancellationToken) => Task.CompletedTask;
+}
+
+public sealed record ToolExecutionResult(bool Success, string Output, bool ExternalEffect, string? FailureFingerprint = null);
+
+public sealed class DenyByDefaultPolicy(IReadOnlySet<string>? allowedTools = null) : IToolPolicyEngine
+{
+    private readonly IReadOnlySet<string> _allowedTools = allowedTools ?? new HashSet<string>(StringComparer.Ordinal);
+    public ToolPolicyDecision Evaluate(string toolName, JsonElement arguments) => _allowedTools.Contains(toolName)
+        ? ToolPolicyDecision.Allow()
+        : ToolPolicyDecision.Deny("Capability is not allowed by policy.");
+}