sharplens-mcp

An MCP server providing 91 semantic analysis tools for .NET/C#, built on Microsoft Roslyn for compiler-accurate code understanding.

Requirements

• .NET 8.0 SDK or later — works with .NET 8, 9, 10, and future versions. Analyzes any .NET 8+ project/solution.

Quick Start

{
  "mcpServers": {
    "sharplens": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "sharplens-mcp"],
      "env": {
        "DOTNET_SOLUTION_PATH": "/path/to/your/Solution.sln"
      }
    }
  }
}

What This Package Does

This npm package is a thin wrapper around the SharpLensMcp .NET global tool. It:

1. Checks that the .NET SDK is installed
2. Installs or updates the SharpLensMcp .NET tool to the exact version matching this npm package
3. Launches sharplens and pipes stdin/stdout for MCP protocol communication

The npm package version and .NET tool version are always kept in sync.

Why SharpLens?

AI systems need compiler-accurate insights that reading source files cannot provide. When an AI uses grep to find usages of a method, it cannot distinguish overloaded methods, partial classes, or interface implementations.

| Approach | Result | |----------|--------| | grep "Save(" | 34 matches including SaveAsync(), SaveButton, XML comments | | find_references | Exactly 8 calls to UserService.Save() |

Features

Navigation & Discovery (23 tools)

Symbol info, go to definition, find references (reports read/write/invocation/cast/typeof/nameof/attribute kind with optional server-side filter), find implementations, find callers, multi-hop call graph with depth bound + cycle detection, type hierarchy, symbol search (glob or fuzzy camel-hump matching), semantic query, type members, batch type members, method signatures, derived types, base types, attributes, containing member, method overloads, attribute usage search, external type inspection (NuGet/BCL/closed-source assemblies with members + XML doc summaries), stack-trace resolution (map a .NET trace to source with compiler mangling undone), applicable extension methods (classic this-parameter and C# 14 extension blocks), symbol documentation with <inheritdoc> resolved recursively, and super-method navigation (jump to the overridden or implemented member).

Analysis (17 tools)

Diagnostics (runs configured DiagnosticAnalyzers — StyleCop, Roslynator, NetAnalyzers, custom — by default; matches CI output), API-surface diff against a git ref, exception-flow analysis (which exceptions can escape a method and where each is caught), structural similar-code search, remove-unused-code computation (generation-only), dead-branch detection (unreachable code from the real control-flow graph), add-missing-imports computation (compiler-accurate), data flow analysis, control flow analysis, change impact analysis, type compatibility, outgoing calls, unused code detection, code validation, complexity metrics, circular dependency detection, and missing members.

Refactoring (16 tools)

Rename, change signature (fully applies declaration + every call site across Foo(...) / new Foo(...) / : this(...) / : base(...) / new(...)), extract method, extract interface, generate constructor, move type to file, split type into a new partial, organize usings, batch organize, batch format, code actions, apply code action by title, implement missing members, encapsulate field, inline variable, and extract variable. Refactoring tools also accept typeName/memberName name-based addressing as an alternative to zero-based coordinates.

Code Generation (3 tools)

Null check generation, equality member generation, test-stub generation (test framework auto-detected from the solution).

Compound Tools (7 tools)

Type overview, method analysis, file overview, method source, batch method source, instantiation options, project health audit (composite dashboard: diagnostics + unused + coupling + coverage in one call) — combining multiple queries to reduce round-trips.

Audit & Quality (10 tools)

Detect god-objects via efferent + afferent coupling + member-count thresholds (audit-time scoring). Find untested code — public/internal surface not transitively reachable from any [Fact]/[Theory]/[Test]/[TestMethod], sorted by cyclomatic complexity so the riskiest gaps surface first. Find tests that cover a symbol. Fine-grained type-usage searches — type instantiations, pattern usages (is/as/patterns), throw sites, and catch blocks for a type. Find async issues (async void, blocking-on-async, unforwarded CancellationToken). Check architecture — enforce dependency rules over the real type-dependency graph. Find naming violations honoring the solution's .editorconfig, with conventional defaults.

Discovery (3 tools)

DI registration scanning, reflection usage detection, and interceptor discovery ([InterceptsLocation] call rerouting, generated code included).

Infrastructure (12 tools)

Health check, unused dependency detection (PackageReference/ProjectReference the compiler never needs), fix-all for a diagnostic across a file, project, or solution, solution loading, document synchronization, project structure, dependency graph, code fixes, apply code fix, NuGet dependency listing, source generator inspection, and generated code viewer.

Configuration

| Environment Variable | Description | Default | |---------------------|-------------|---------| | DOTNET_SOLUTION_PATH | Auto-load .sln or .slnx on startup | (none) | | SHARPLENS_LOG_LEVEL | Trace/Debug/Information/Warning/Error | Information | | SHARPLENS_TIMEOUT_SECONDS | Operation timeout | 30 | | SHARPLENS_MAX_DIAGNOSTICS | Maximum diagnostics to return | 100 | | SHARPLENS_ENABLE_SEMANTIC_CACHE | Enable semantic model caching | true | | SHARPLENS_ABSOLUTE_PATHS | Use absolute paths instead of relative | false |

The legacy ROSLYN_* spellings (e.g. ROSLYN_LOG_LEVEL) remain accepted as a one-release migration fallback.

Uninstall

If installed globally: npm uninstall -g sharplens-mcp (automatically removes the .NET tool)

If used via npx: dotnet tool uninstall --global SharpLensMcp

Documentation

Full documentation, tool reference, and architecture details: GitHub