Repl.Mcp 0.11.0-dev.124

.NET 10.0 This package targets .NET 10.0. The package is compatible with this framework or higher.
This is a prerelease version of Repl.Mcp.
There is a newer prerelease version of this package available.
See the version list below for details. 
dotnet add package Repl.Mcp --version 0.11.0-dev.124
                    


                    

                
NuGet\Install-Package Repl.Mcp -Version 0.11.0-dev.124
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="Repl.Mcp" Version="0.11.0-dev.124" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Repl.Mcp" Version="0.11.0-dev.124" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Repl.Mcp" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add Repl.Mcp --version 0.11.0-dev.124
                    


                    

                
#r "nuget: Repl.Mcp, 0.11.0-dev.124"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package Repl.Mcp@0.11.0-dev.124
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=Repl.Mcp&version=0.11.0-dev.124&prerelease
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Repl.Mcp&version=0.11.0-dev.124&prerelease
                    


                            Install as a Cake Tool

Repl.Mcp

Website: repl.yllibed.org

MCP server integration for Repl Toolkit — expose your command graph as AI agent tools, resources, prompts, and MCP Apps UI via the Model Context Protocol.

Use Repl.Mcp when you already have, or want to build, a Repl command graph and make the same operations available to AI agents without writing a separate MCP server by hand.

Install

dotnet add package Repl.Mcp

One line to add

using Repl.Mcp;

app.UseMcpServer();

Your commands become MCP tools. Route constraints become JSON Schema. Annotations become safety hints.

myapp mcp serve   # AI agents connect here
myapp              # still a CLI / interactive REPL

IReplInteractionChannel user feedback maps to MCP-native transports:

  • progress → progress notifications
  • notice / warning / problem feedback → MCP message notifications

Keep operator logging on ILogger; do not rely on user-facing interaction as a logging sink.

Agent configuration

Most MCP clients use the same shape:

{
  "mcpServers": {
    "myapp": {
      "command": "myapp",
      "args": ["mcp", "serve"]
    }
  }
}

Use the executable that matches your app packaging. For local project samples, build once and use dotnet run --no-build --project ... -- mcp serve so host startup does not rebuild or write build output to stdout.

MCP Apps

Repl.Mcp can also expose MCP Apps UI resources:

This support is experimental in the current version. AsMcpAppResource() handlers should return generated HTML as string, Task<string>, or ValueTask<string>; richer return shapes and asset helpers may be added later.

app.Map("contacts dashboard", (ContactStore contacts) =>
        $"<!doctype html><html><body>{contacts.All.Count} contacts</body></html>")
    .WithDescription("Open the contacts dashboard")
    .AsMcpAppResource()
    .WithMcpAppBorder()
    .WithMcpAppDisplayMode(McpAppDisplayModes.Fullscreen);

Clients with MCP Apps support render the generated ui:// resource. Other MCP clients still receive the command's normal launcher text instead of raw HTML.

What agents see

You write Agents get
.ReadOnly() readOnlyHint — call autonomously
.Destructive() destructiveHint — ask for confirmation
.Idempotent() retry-safe hint
.OpenWorld() external-system hint
.LongRunning() long-running-operation hint
.AsResource() MCP resource with repl:// URI
.AsMcpAppResource() MCP Apps HTML resource with ui:// URI
.WithMcpAppBorder() MCP Apps border/background preference
.WithMcpAppDisplayMode(McpAppDisplayModes.Fullscreen) MCP Apps display preference
.AsPrompt() MCP prompt template
.AutomationHidden() Not visible to agents
{id:guid} { "type": "string", "format": "uuid" }
[Description("...")] Schema description field

Safety guidelines

Annotate every command that is visible to agents:

app.Map("contacts list", handler).ReadOnly();

app.Map("contacts import {file}", handler)
    .OpenWorld()
    .LongRunning();

app.Map("contacts delete {id:int}", handler)
    .Destructive();

app.Map("debug reset", handler)
    .AutomationHidden();

Unannotated tools force agents to assume the worst. Use .ReadOnly() for safe queries, .Destructive() for important mutations, .OpenWorld() for external systems, .LongRunning() for operations that should use call-now / poll-later patterns, and .AutomationHidden() for commands that should stay available to humans but invisible to MCP automation.

Prefer returning JSON-friendly objects instead of writing prose-only output. Structured results are easier for agents to inspect, retry, test, and summarize.

Works with

Claude Desktop, Claude Code, VS Code Copilot, Cursor, and any MCP-compatible agent.

MCP Apps host support varies. VS Code currently renders MCP Apps inline; hosts that support display mode requests can honor preferredDisplayMode.

Docs

Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
0.11.0-dev.126 37 7/9/2026
0.11.0-dev.125 36 7/9/2026
0.11.0-dev.124 36 7/9/2026
0.11.0-dev.123 45 7/9/2026
0.11.0-dev.108 46 7/8/2026
0.11.0-dev.68 47 7/5/2026
0.11.0-dev.67 49 7/4/2026
0.11.0-dev.63 78 6/26/2026
0.11.0-dev.56 55 6/24/2026
0.11.0-dev.51 5,983 5/9/2026
0.11.0-dev.6 5,512 5/2/2026
0.11.0-dev.4 51 5/1/2026
0.11.0-dev.3 103 4/25/2026
0.10.0 1,008 4/25/2026
0.10.0-dev.83 67 4/25/2026
0.10.0-dev.77 1,009 4/20/2026
0.10.0-dev.76 69 4/19/2026
0.10.0-dev.59 72 4/13/2026
0.10.0-dev.58 3,165 4/7/2026
0.10.0-dev.52 62 4/7/2026
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