Agentic .NET MCP (AgenticDotNet)

A Roslyn-powered MCP server that gives AI agents semantic understanding of a .NET solution — diagnostics, navigation, symbol search, and automated code fixes — backed by the same compiler pipeline used by Visual Studio and Rider.

Installation

Global

dotnet tool install -g AgenticDotNet

Per-project (tool manifest)

This is the recommended approach for team projects — the tool version is pinned in source control and anyone can restore it with a single command.

# Create the manifest if one doesn't exist yet
dotnet new tool-manifest

# Install into the manifest (.config/dotnet-tools.json)
dotnet tool install AgenticDotNet

Commit .config/dotnet-tools.json. Anyone who clones the repo can then run:

dotnet tool restore

When using a local install, invoke the tool with dotnet prefix:

dotnet agentic <path-to-solution.sln|.slnx>

And use dotnet agentic as the command in your MCP config (see below).

Usage

agentic <path-to-solution.sln|.slnx>

The path can be absolute or relative to the current working directory. The server communicates over stdio (MCP standard transport), so it is meant to be launched by an MCP client, not used interactively.

Example MCP client config (Claude Desktop / Claude Code)

Global install:

{
  "mcpServers": {
    "agentic-dotnet": {
      "command": "agentic",
      "args": ["C:/Work/MyProject/MyProject.sln"]
    }
  }
}

Local (per-project) install — run dotnet tool restore first:

{
  "mcpServers": {
    "agentic-dotnet": {
      "command": "dotnet",
      "args": ["agentic", "C:/Work/MyProject/MyProject.sln"]
    }
  }
}

Tools

Diagnostics

Tool	Description
get_diagnostics	Compiler errors/warnings and analyzer diagnostics (CA*, IDE*) for the whole solution or a specific file. Respects AnalysisMode, AnalysisLevel, and .editorconfig severity overrides.
get_code_fixes	Lists available automated code fixes for diagnostics in a file.
apply_code_fix	Applies a specific code fix and writes changes to disk.

Navigation

Tool	Description
get_solution_projects	Lists all projects with paths, assembly names, and output kind.
get_project_namespaces	All namespaces declared in a project, sorted alphabetically.
get_types_in_namespace	All types (classes, interfaces, enums, structs, delegates) in a namespace.
get_type_info	Full type detail: base type, interfaces, constructors, methods, properties, fields, events.

Symbols

Tool	Description
find_symbol	Case-insensitive partial-name search across the solution. Supports kind filters (class, method, property, …).
find_implementations	All types that implement an interface or derive from a class (transitive).
find_overrides	All overrides of a virtual or abstract method.
rename_symbol	Renames a symbol across the entire solution and writes all changed files to disk.

How it works

On the first tool call the server opens the solution via MSBuildWorkspace, which uses the installed .NET SDK to evaluate all project files. Subsequent calls do an incremental refresh: only files whose LastWriteTimeUtc changed since the last call are re-parsed. Roslyn reuses all unchanged compilation state, so repeated calls are fast — the same incremental pipeline that powers IDE analyzers.

Analyzer diagnostics are produced by running project.AnalyzerReferences through CompilationWithAnalyzers with project.AnalyzerOptions, which includes the .editorconfig provider. This means severity overrides, code-style rules, and custom analyzers all behave exactly as they do during dotnet build.

Source-generated files are included: get_diagnostics covers generated syntax trees, and file-specific queries fall back through GetSourceGeneratedDocumentsAsync and the raw compilation tree list.

Development

Build

dotnet build

Debug with MCP Inspector

MCP Inspector lets you call tools interactively against a running server:

npx @modelcontextprotocol/inspector .\AgenticDotNet\bin\Debug\net10.0\agentic.exe .\AgenticDotNet.slnx

Or after dotnet pack + local tool install:

dotnet tool install -g AgenticDotNet --add-source ./AgenticDotNet/nupkg
npx @modelcontextprotocol/inspector agentic .\AgenticDotNet.slnx

The Inspector opens a browser UI where you can invoke each tool and inspect the JSON request/response.