A read-only C# and .NET code analysis tool built around OmniSharp-Roslyn, which provides compiler diagnostics and information about code symbols. It can understand projects and solutions without Visual Studio.

Use it to inspect C# and .NET diagnostics, navigate definitions, find references across a solution, and view inferred types and documentation.

It exposes compile errors, warnings, definitions, references, and types without modifying source files, making unfamiliar C# code easier to investigate.

csharp-lsp — Skill for Claude Code by MSApps-Mobile/claude-plugins

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add MSApps-Mobile/claude-plugins --skill csharp-lsp

Clone the repo

git clone --depth 1 https://github.com/MSApps-Mobile/claude-plugins

Made for: Claude Code.

Or install csharp-lsp, the plugin that ships this one along with the rest of its 1 skill.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/csharp-lsp/github.svg)](https://agentmods.dev/skills/msapps-mobile/claude-plugins/csharp-lsp)

Your own site

<a href="https://agentmods.dev/skills/msapps-mobile/claude-plugins/csharp-lsp"><img src="https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/csharp-lsp/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/msapps-mobile/claude-plugins/csharp-lsp"><img src="https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/csharp-lsp.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 181 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,503 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00181	$0.01503
Opus 5.5	$0.00072	$0.00601
Sonnet 5.5	$0.00036	$0.00301
Haiku 4.5	$0.00018	$0.00150

Measured today against content hash 1823834eb272, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

csharp-lsp scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/csharp-lsp/skills/csharp-lsp/SKILL.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

C# LSP — OmniSharp Integration

Overview

The C# LSP plugin delivers real-time code intelligence for C# and .NET projects by connecting Claude to omnisharp — the Roslyn-based language server that ships as a standalone .NET tool. It provides Roslyn-grade diagnostics, navigation, and symbol information for .cs and .csx files without modifying code or producing side effects.

Key Features

Diagnostics: Compile errors, nullable-reference warnings, unused using directives, analyzer rules (Roslyn, StyleCop, .NET built-in)
Navigation: Go-to-definition (follows using aliases, partial classes, [Generator] source-generated members, metadata references) and find-references across the whole solution graph
Type Information: Hover to see inferred types, generic instantiations, async return types, and XML doc comments
Solution-Aware: Indexes from .sln / .slnx / bare .csproj roots — no Visual Studio required
Read-Only Analysis: no file modifications, no credentials. OmniSharp still evaluates the opened project's MSBuild files, so use it on trusted projects only (the plugin asks OmniSharp to keep analyzers and package auto-restore off — best effort; a project's omnisharp.json can override it)

Workflow Process

The plugin operates in three phases (same contract as swift-lsp / kotlin-lsp / python-lsp / typescript-lsp):

Plan: LSP analyzes the solution and reports current diagnostics before any edits
Act: Claude edits .cs / .csx files; the server returns updated diagnostics as the buffer changes
Verify: Claude re-reads diagnostics post-edit to confirm no regressions were introduced

Setup Requirements

Prerequisites:

.NET SDK ≥ 6.0 on PATH (for OmniSharp's runtime)
omnisharp (OmniSharp-Roslyn) on PATH

Install:

# macOS (Homebrew)
brew install omnisharp

# Linux / Windows / macOS — GitHub releases
# Download the latest omnisharp-osx-arm64-net6.0.tar.gz (or your platform)
# from https://github.com/OmniSharp/omnisharp-roslyn/releases
# Unpack and symlink/move `omnisharp` onto PATH.

# Alternative: .NET global tool
dotnet tool install -g Microsoft.OmniSharp.DotNet.GlobalTool

Read the full file on GitHub · 108 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

today First seen · 108 lines · 181 tokens per session scan A 1823834eb272

Subscribe to this mod's changes

csharp-lsp is a skill published in the GitHub repository MSApps-Mobile/claude-plugins (10 stars, last pushed today), licensed MIT. It adds 181 tokens to every session and 1,503 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-18.

C# and .NET Debugging Languages agent-safety ai-agents ai-governance claude claude-plugins

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