CWM.RoslynNavigator 0.7.0

CWM.RoslynNavigator — Roslyn MCP Server

Token-efficient .NET codebase navigation via Roslyn semantic analysis.

Overview

CWM.RoslynNavigator is a Model Context Protocol (MCP) server that provides Claude Code with semantic understanding of .NET solutions. Instead of reading entire source files (hundreds of tokens), Claude can query for specific symbols, references, and type hierarchies (tens of tokens).

Prerequisites

• .NET 10 SDK
• A .NET solution file (.sln or .slnx)

Tools

Installation

As a Global Tool (Recommended)

# Install once
dotnet tool install -g CWM.RoslynNavigator

# Register with Claude Code (no --solution needed!)
claude mcp add --scope user cwm-roslyn-navigator -- cwm-roslyn-navigator

The server auto-discovers the solution from MCP workspace roots. No per-project configuration needed.

You can also add it manually to your Claude Code global settings (~/.claude/settings.json):

{
  "mcpServers": {
    "cwm-roslyn-navigator": {
      "command": "cwm-roslyn-navigator"
    }
  }
}

Optional override: Pass --solution <path> to specify a solution file or directory explicitly:

{
  "mcpServers": {
    "cwm-roslyn-navigator": {
      "command": "cwm-roslyn-navigator",
      "args": ["--solution", "${workspaceFolder}"]
    }
  }
}

As a Local Tool (per-repo)

dotnet new tool-manifest   # if you don't have one
dotnet tool install CWM.RoslynNavigator

Then add to your project's .mcp.json:

{
  "mcpServers": {
    "cwm-roslyn-navigator": {
      "command": "dotnet",
      "args": ["tool", "run", "cwm-roslyn-navigator", "--", "--solution", "${workspaceFolder}"]
    }
  }
}

From Source (for contributors)

dotnet run --project mcp/CWM.RoslynNavigator/src/CWM.RoslynNavigator.csproj -- --solution /path/to/your/Solution.sln

Solution Discovery

The server resolves the solution file in this order:

1. Explicit --solution argument — Pass a .sln/.slnx file path directly, or a directory to scan recursively
2. Working directory scan — If no argument, scans the current working directory recursively for solution files
3. MCP roots discovery — On the first tool call, if no solution was found at startup, the server requests workspace roots from the MCP host (e.g., Claude Code) and scans those directories. This is a one-shot attempt — if no solution is found, it won't retry. This enables true zero-arg global tool operation.
4. Deterministic selection — Shallowest solution wins (BFS); within the same depth, alphabetical (case-insensitive) ordering is used

Recursive Search

Discovery searches up to 3 levels deep using breadth-first search, so a solution at src/MyApp.sln or src/backend/Api/Api.sln is found automatically.

The following directories are skipped during scanning: .git, .vs, .idea, node_modules, bin, obj, packages, artifacts, TestResults, .claude.

Architecture

Program.cs              → MSBuildLocator → Host → MCP stdio transport
WorkspaceManager.cs     → MSBuildWorkspace lifecycle, file watching, compilation caching
WorkspaceInitializer.cs → BackgroundService triggers workspace load on startup
SolutionDiscovery.cs    → Auto-detect .sln/.slnx from args or working directory
SymbolResolver.cs       → Cross-project symbol resolution with disambiguation
Tools/                  → MCP tool implementations (15 read-only tools)
Responses/              → Token-optimized JSON response DTOs

Scaling

Development

# Build
dotnet build mcp/CWM.RoslynNavigator/CWM.RoslynNavigator.slnx

# Run tests
dotnet test mcp/CWM.RoslynNavigator/CWM.RoslynNavigator.slnx

# Run manually against a directory
dotnet run --project mcp/CWM.RoslynNavigator/src/CWM.RoslynNavigator.csproj -- --solution /path/to/your/project/

# Run manually against a solution file
dotnet run --project mcp/CWM.RoslynNavigator/src/CWM.RoslynNavigator.csproj -- --solution /path/to/your/Solution.sln

Changelog

0.7.0

• Performance optimizations across all tools:
  • find_references — Document text caching (200 async calls → ~10) + maxResults cap (default 100)
  • find_dead_code — Fast name-based pre-filter skips ~80-90% of expensive Roslyn reference searches
  • get_dependency_graph — O(1) file-to-project lookup via pre-built dictionary
  • detect_circular_dependencies — Reduced ToDisplayString() allocations with IsUserType() helper
  • SymbolResolver — SymbolEqualityComparer.Default for dedup instead of string allocation
  • Parallel compilation warming (Parallel.ForEachAsync, max 4 concurrent) for ~2-4x faster startup
  • Consolidated 4 duplicate MakeRelativePath into shared SymbolResolver.MakeRelativePath

0.6.0

• MCP roots discovery — When no solution is found at startup, tools now request workspace roots from the MCP host on the first call and auto-discover the solution. One-shot, thread-safe attempt via EnsureReadyOrStatusAsync.
• Project restructured — Source moved to src/ and tests/ layout with a new .slnx solution file.
• Unified readiness check — All 15 tools use EnsureReadyOrStatusAsync instead of inline state checks, reducing boilerplate and ensuring consistent lazy-init behavior.

0.5.2

• Recursive solution discovery (BFS up to 3 levels deep).

0.5.1

• Expanded README with installation, architecture, and scaling docs.

0.5.0

• Initial NuGet release as a dotnet tool. 15 read-only Roslyn MCP tools.