From 63f19493a018e63e5ab98f42c1eef6b21dfa375b Mon Sep 17 00:00:00 2001 From: AJ Isaacs Date: Sun, 16 Aug 2026 22:51:44 -0400 Subject: [PATCH] fix: keep MCP protocol stdout clean --- PepMcp/Program.cs | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/PepMcp/Program.cs b/PepMcp/Program.cs index e371a37..e519b05 100644 --- a/PepMcp/Program.cs +++ b/PepMcp/Program.cs @@ -1,7 +1,14 @@ using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Hosting; +using Microsoft.Extensions.Logging; var builder = Host.CreateApplicationBuilder(args); + +// MCP stdio requires stdout to contain JSON-RPC messages only. Route every +// Microsoft logger event to stderr so it cannot corrupt the protocol stream. +builder.Logging.ClearProviders(); +builder.Logging.AddConsole(options => options.LogToStandardErrorThreshold = LogLevel.Trace); + builder.Services .AddMcpServer() .WithStdioServerTransport()