feat(12-02): catch BrokenCircuitException in McpToolDispatcher, rethrow as McpException (ROB-03)

Author: OgeonX-Ai

src/GsdOrchestrator/Mcp/McpToolDispatcher.cs

@@ -1,13 +1,14 @@
 using System.Text.Json.Nodes;
 using Microsoft.Extensions.Logging;
 using Polly;
+using Polly.CircuitBreaker;
 using Polly.Registry;
 
 namespace GsdOrchestrator.Mcp;
 
 /// <summary>
-/// Wraps IMcpClient with resilience (Polly retry), logging, and secondary rate limit
-/// special-casing. Inject and use this instead of calling IMcpClient directly.
+/// Wraps IMcpClient with resilience (Polly retry + circuit breaker), logging, and secondary
+/// rate limit special-casing. Inject and use this instead of calling IMcpClient directly.
 /// </summary>
 public sealed class McpToolDispatcher
 {
@@ -28,21 +29,30 @@ public McpToolDispatcher(
     public async Task<McpToolResult> CallAsync(
         string tool, JsonObject args, CancellationToken ct = default)
     {
-        return await _pipeline.ExecuteAsync(async token =>
+        try
         {
-            try
+            return await _pipeline.ExecuteAsync(async token =>
             {
-                return await _client.CallToolAsync(tool, args, token);
-            }
-            catch (McpException ex) when (ex.IsSecondaryRateLimit)
-            {
-                // Secondary rate limit: MUST wait at least 60 seconds — bypass Polly retry
-                _logger.LogWarning(
-                    "Secondary rate limit on '{Tool}'. Waiting 65s before retry.", tool);
-                await Task.Delay(TimeSpan.FromSeconds(65), token);
-                return await _client.CallToolAsync(tool, args, token);
-            }
-        }, ct);
+                try
+                {
+                    return await _client.CallToolAsync(tool, args, token);
+                }
+                catch (McpException ex) when (ex.IsSecondaryRateLimit)
+                {
+                    // Secondary rate limit: MUST wait at least 60 seconds — bypass Polly retry
+                    _logger.LogWarning(
+                        "Secondary rate limit on '{Tool}'. Waiting 65s before retry.", tool);
+                    await Task.Delay(TimeSpan.FromSeconds(65), token);
+                    return await _client.CallToolAsync(tool, args, token);
+                }
+            }, ct);
+        }
+        catch (BrokenCircuitException)
+        {
+            throw new McpException(
+                "MCP circuit breaker open — too many consecutive failures",
+                isTransient: false);
+        }
     }
 
     public Task<IReadOnlyList<McpTool>> ListToolsAsync(CancellationToken ct = default) =>