roslyn-codelens

Roslyn CodeLens MCP Server

A Roslyn-based MCP server that gives AI agents deep semantic understanding of .NET codebases — type hierarchies, call graphs, DI registrations, diagnostics, refactoring, and more.

Hosted deployment

A hosted deployment is available on Fronteir AI.

Features

• find_implementations — Find all classes/structs implementing an interface or extending a class
• find_callers — Find every call site for a method, property, or constructor
• find_event_subscribers — Every += / -= site for an event symbol, with resolved handler and subscribe/unsubscribe tag
• find_tests_for_symbol — List xUnit/NUnit/MSTest methods that exercise a production symbol; opt-in transitive walk through helpers
• get_test_summary — Per-project inventory of test methods with framework, attribute kind, data-row count, location, and production symbols referenced
• find_uncovered_symbols — Public methods and properties no test transitively reaches; sorted by cyclomatic complexity for prioritization
• generate_test_skeleton — Emit a compilable test-class skeleton (as text) for a method or type. Auto-detects xUnit/NUnit/MSTest; surfaces constructor dependencies as TodoNotes; returns a suggested file path. Closes the loop with find_uncovered_symbols
• get_type_hierarchy — Walk base classes, interfaces, and derived types
• get_di_registrations — Scan for DI service registrations
• get_project_dependencies — Get the project reference graph
• get_symbol_context — One-shot context dump for any type
• get_public_api_surface — Enumerate every public/protected type and member in production projects; flat, deterministically-sorted list suitable for API review or breaking-change baselines.
• find_breaking_changes — Diff the current API against a baseline JSON or DLL; report removed members, kind changes, and accessibility changes with Breaking/NonBreaking severity.
• find_reflection_usage — Detect dynamic/reflection-based usage
• find_references — Find all references to any symbol (types, methods, properties, fields, events)
• go_to_definition — Find the source file and line where a symbol is defined
• get_method_source — Full declaration source (XML docs, attributes, signature, body — original formatting) for one or many members by name in a single call: methods (all overloads), constructors, properties, indexers, fields, events; per-item statuses (ok/notFound/ambiguous/metadata/unsupportedKind) so a batch never fails wholesale
• resolve_stack_trace — Map a pasted .NET stack trace to file/line/symbol, undoing compiler name mangling (async/iterator state machines, lambdas, local functions, generic arity); handles inner-exception chains, log-prefixed lines, and Demystifier traces
• get_diagnostics — List compiler errors, warnings, and Roslyn analyzer diagnostics
• get_code_fixes — Get available code fixes with structured text edits for any diagnostic
• search_symbols — Fuzzy workspace symbol search by name
• get_nuget_dependencies — List NuGet package references per project
• find_attribute_usages — Find types and members decorated with a specific attribute
• find_obsolete_usage — Every [Obsolete] call site grouped by deprecation message and severity, errors first; for planning migrations
• find_circular_dependencies — Detect cycles in project or namespace dependency graphs
• get_complexity_metrics — Cyclomatic complexity analysis per method
• find_naming_violations — Check .NET naming convention compliance