AmazingMCP — MCP Server for .NET / C# Codebases

from remleo

An MCP server that gives AI agents deep understanding of C# codebases via Roslyn — type search, dependency graphs, usage analysis, and architecture overviews, all from a live in-memory compilation.

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AmazingMCP — MCP Server for .NET / C# Codebases

An MCP server that gives AI agents deep understanding of C# codebases via Roslyn — type search, dependency graphs, usage analysis, and architecture overviews, all from a live in-memory compilation.

MCP Tools

Tool	Description
`query_symbol`	Find types, members (methods, properties, fields), extension methods, constants, and enum values across the solution and NuGet packages
`get_type_details`	Full type info: properties, methods, base types, nested types (including NuGet)
`query_usages`	Find all usages of a type across the solution: method calls, constructor calls, property/field read and write, generic arguments and constraints, return types, parameter types, inheritance, `nameof`, `typeof`, `is`/`as`. Supports predicate filtering and scan scope control
`read_cs_file_digest`	Token-efficient entry point for large `.cs` files (hundreds or thousands of lines): returns a structural outline — types and members with line numbers, no implementations. Use this first, then fetch only the members you need with `read_large_cs_file`
`read_large_cs_file`	Read specific member implementations from a `.cs` file by name filter — use after `read_cs_file_digest` to load only what's relevant instead of the entire file
`decompile_type`	Decompile any type from a NuGet assembly to C# source — no external tools required, ILSpy is built in
`code_lens`	Resolve fully-qualified types for any line range in a `.cs` file: local variables, field/property types, method call signatures, object creations, and declarations — all from the Roslyn semantic model
`get_project_design`	High-level architecture map: abstraction groups by namespace and inter-group dependencies
`get_project_design_details`	Detailed view of abstractions and implementations for specified namespaces (supports `*` wildcard)

Features

One server, any number of solutions — start it once and point it at any project per call, no restart needed when switching between solutions.
Live in-memory compilation — opens .sln/.slnx via MSBuild Workspaces and compiles all projects in memory. All tools run against a real Roslyn semantic model, not text search.
Incremental cache — workspace is cached with file watchers. .cs changes trigger incremental recompilation; .csproj/.sln changes invalidate the full cache. First call per solution is slow; subsequent calls are instant.
NuGet-aware — NuGet types are fully resolved and searchable alongside source types. query_symbol, get_type_details, and decompile_type work on any referenced package.

Documentation

Contributing

PRs and issues are welcome. Please open an issue before submitting a large change.

git clone https://github.com/remleo/AmazingMCP
cd AmazingMCP
dotnet build
dotnet test

License

MIT

Installation

dotnet tool install -g HoldMyCoolantMeatbag.AmazingMCP

Requires .NET 10 SDK.

Usage

AmazingMCP <options>

# example:
AmazingMCP --urls=http://localhost:7777 --Symbol:QueryOutputLineLimit=50 --ReadCs:ReadOutputMaxLength=50000

# see all options:
AmazingMCP --help

The server starts on http://localhost:7777 by default.

Command-line options

Option	Default	Description
`--urls`	`http://localhost:7777`	Listening URL
`--Symbol:QueryOutputLineLimit`	`100`	Max output lines for `query_symbol`
`--ReadCs:ReadOutputMaxLength`	`20000`	Max output characters for `read_large_cs_file`
`--ProjectDesign:DetailsOutputMaxLength`	`30000`	Max output characters for `get_project_design_details`
`--ProjectDesign:DetailsXmlDocSummaryMaxLength`	`2000`	Max XML doc summary characters in `get_project_design_details`
`--QueryUsages:QueryMatchLimit`	`200`	Max usage matches for `query_usages`
`--Diagnostics:IncludeExceptionDetails`	`false`	Include full exception details in tool error responses (for diagnostics)
`--HttpServerTransport:IdleTimeout`	`7.00:00:00`	MCP session idle timeout — how long a session is kept alive without activity (e.g. `7.00:00:00` for 7 days, `2:00:00` for 2 hours)
`--DisabledTools`	(none)	Comma-separated list of tool names to disable (e.g. `code_lens,get_project_design`)

MCP Client Configuration

Add to your MCP client config (Claude Desktop, JetBrains AI, Kiro, etc.):

{
  "mcpServers": {
    "AmazingMCP": {
      "type": "http",
      "url": "http://localhost:7777"
    }
  }
}

Then start the server manually in your terminal:

AmazingMCP --urls=http://localhost:7777 <other options>

Or add a launcher entry so the client starts the server automatically:

{
  "mcpServers": {
    "AmazingMCP": {
      "type": "http",
      "url": "http://localhost:7777"
    },
    "AmazingMCP Launcher": {
      "command": "AmazingMCP",
      "args": ["--urls=http://localhost:7777"]
    }
  }
}