Sharplens MCP

What pzalutski-pixel/sharplens-mcp MCP server does

The pzalutski-pixel/sharplens-mcp MCP server gives coding agents semantic access to C# and .NET solutions through Microsoft Roslyn. Rather than treating source files as plain text, it resolves symbols, types, members, overloads, inheritance, attributes, and external assembly information using the compiler’s model.

Its tool set covers navigation, discovery, diagnostics, code-quality analysis, impact assessment, and refactoring support. Examples include locating definitions and references, finding callers and implementations, constructing bounded call graphs, comparing a public API with a Git reference, tracing exception flow, identifying dead branches, and resolving pasted stack traces to source locations. Several operations support batches or preview-style generation so an agent can inspect proposed changes before applying them.

How it works

The server maintains an in-memory representation of the loaded solution for responsive queries. Set DOTNET_SOLUTION_PATH to load a .sln or .slnx file at startup, or call load_solution before using analysis tools. Responses use a structured success/error/data shape and can include suggested follow-up tools. Coordinates are zero-based.

Roslyn-based resolution is useful for cases where textual matching is ambiguous, such as overloaded methods, partial types, inheritance, dispatch, or read/write reference classification. The server can also inspect NuGet, BCL, and other external assembly types when the solution provides the relevant references.

Setup and configuration

Install the pzalutski-pixel/sharplens-mcp MCP server with the SharpLensMcp global .NET tool or run the npm package with npx -y sharplens-mcp. A stdio client configuration can invoke the npm package and pass DOTNET_SOLUTION_PATH in its environment. The README specifically documents Claude Code setup through a project .mcp.json file.

Supported configuration variables are:

• DOTNET_SOLUTION_PATH: startup solution path; if absent, use load_solution.
• SHARPLENS_ABSOLUTE_PATHS: return absolute rather than relative paths.
• SHARPLENS_LOG_LEVEL: set logging verbosity.
• SHARPLENS_TIMEOUT_SECONDS: set the long-operation timeout.
• SHARPLENS_MAX_DIAGNOSTICS: limit returned diagnostics.
• SHARPLENS_ENABLE_SEMANTIC_CACHE: enable or disable semantic caching.

Tools and capabilities

The pzalutski-pixel/sharplens-mcp MCP server exposes tools for:

• Symbol lookup, definitions, references, implementations, callers, call graphs, and paths between methods.
• Type hierarchies, derived and base types, members, overloads, attributes, documentation, extension methods, and super methods.
• Compiler and analyzer diagnostics, API compatibility checks, data-flow and control-flow analysis, exception flow, and change-impact analysis.
• Similar-code detection, dead-code and unreachable-branch analysis, stack-trace resolution, and external type inspection.
• Refactoring and generation workflows, including safe previews and batch operations, where provided by the server.

Limitations and notes

The in-memory model can become stale after files are changed by external editor or file tools. Call sync_documents for modified, created, or deleted C# files. Changes made through the server’s own refactoring tools are updated automatically; project-file changes require load_solution instead.

If no startup solution path is configured, analysis cannot begin until load_solution has been called. The README also notes that tool names no longer use the older roslyn: prefix; current names omit it, while prefixed aliases are retained temporarily for one migration release.