俄语版本见下文 / Russian version below
这是一个小型模型上下文协议 (MCP) 服务器，允许 LLM 以 C# 形式读取 .NET 程序集。它是官方 ILSpy CLI (ilspycmd) 的轻量级封装，通过 stdio 公开，因此任何支持 MCP 的客户端都可以列出类型、反编译单个类、将整个程序集反编译为项目树，或在反编译后的源码中进行 grep 搜索。
LLM 擅长阅读源代码，而不是原始的 IL 字节码。ILSpy 已经可以将 CIL 转换为忠实的 C# 代码，但从聊天代理中调用它很麻烦——你最终不得不手动调用 ilspycmd 并将输出粘贴回对话中。该服务器将此循环形式化：
首先使用 list-types，这样模型无需将数兆字节的反编译内容放入上下文中即可知道要查看哪个类型。
使用 decompile-type 进行针对性读取——一次一个完全限定的类。
当模型确实需要整个项目树时（例如在运行全项目 grep 之前），使用 decompile-assembly。
search-source 会进行一次反编译，缓存输出，并在所有生成的 .cs 文件中进行 grep 搜索。后续搜索将重用缓存的树。
目标程序集永远不会被执行。一切都是静态的。
它还处理了现代常见的 .NET 6/7/8 单文件部署情况——将 path 指向已发布的 .exe，ILSpy 10+ 会自动解析嵌入的核心程序集。
Related MCP server: dotnet-sherlock-mcp
工具 | 功能 |
| 列出程序集中声明的类型。可选 |
| 将一个完全限定的类型反编译为 C#。可通过 |
| 反编译为 |
| 反编译（一次，缓存）并对 C# 树进行正则表达式 grep；返回文件/行号/代码片段。 |
# 1. ILSpy CLI (one-time, requires .NET SDK 6+)
dotnet tool install --global ilspycmd
# 2. This server
git clone https://github.com/beekamai/mcp-dotnet.git
cd mcp-dotnet
npm install
npm run build如果 ilspycmd 不在 PATH 中，请将 ILSPYCMD 环境变量设置为其绝对路径。服务器还会自动检测 Windows 上的默认 %USERPROFILE%\.dotnet\tools\ilspycmd.exe 位置以及 POSIX 上的 ~/.dotnet/tools/ilspycmd 位置。
通过 stdio 将其连接到任何支持 MCP 的客户端：
your-mcp-client mcp add dotnet --scope user -- node /absolute/path/to/mcp-dotnet/dist/index.js所有工具都接受绝对路径。MCP 客户端和此服务器之间的工作目录差异很常见，因此服务器拒绝进行猜测。
decompile-assembly 以及在全新程序集上的首次 search-source 可能需要几十秒到几分钟不等，具体取决于大小——超时时间为 10 分钟。
search-source 默认将反编译后的树缓存到 <assemblyDir>/.mcp-dotnet-<assemblyName>/ 下。传递显式的 outDir 以控制位置，或删除缓存以强制重新反编译。
服务器将 ilspycmd 作为子进程运行，且从不暴露其 stdin。目标程序集的代码在任何时候都不会被执行。
MIT。
Небольшой MCP-сервер, который даёт языковой модели возможность читать
.NET-сборки как C#-исходники. Это тонкая обёртка над официальной
консольной утилитой ILSpy (ilspycmd) поверх stdio: модель может получить
список типов, декомпилировать один класс, развернуть всю сборку в дерево
.cs-файлов или прогнать regex по исходнику.
LLM хорошо читают исходный код и плохо — IL. ILSpy и так умеет превращать
CIL в адекватный C#, но дёргать ilspycmd руками из чата неудобно — каждый
раз shell-out и копипаст в контекст. Этот сервер формализует цикл:
Сначала list-types, чтобы модель не тащила мегабайты декомпила в
контекст ради того, чтобы выяснить какой класс ей нужен.
decompile-type — точечно один полностью-квалифицированный тип.
decompile-assembly — когда нужен весь проектный tree (например, чтобы
потом сделать project-wide grep).
search-source — декомпилирует один раз, кэширует результат и ищет regex
по всем .cs. Повторные поиски используют кэш.
Целевую сборку никто не запускает. Всё статично.
Сервер также корректно работает с single-file deployment .NET 6/7/8 —
указываешь path на опубликованный .exe, ILSpy 10+ сам находит
встроенный основной assembly.
Тул | Что делает |
| Список типов сборки. Опциональный фильтр |
| Декомпиляция одного типа в C#. С опциональным IL через |
| Развёртывает сборку в папку |
| Один раз декомпилирует (с кэшем), потом regex-grep по |
# 1. ILSpy CLI (один раз, нужен .NET SDK 6+)
dotnet tool install --global ilspycmd
# 2. Сам сервер
git clone https://github.com/beekamai/mcp-dotnet.git
cd mcp-dotnet
npm install
npm run buildЕсли ilspycmd не попал в PATH — выставь переменную окружения ILSPYCMD
с абсолютным путём. Сервер также автоматически находит дефолтные пути:
%USERPROFILE%\.dotnet\tools\ilspycmd.exe на Windows и
~/.dotnet/tools/ilspycmd на POSIX.
Подключение к MCP-клиенту через stdio:
your-mcp-client mcp add dotnet --scope user -- node /абсолютный/путь/к/mcp-dotnet/dist/index.jsВсе тулы принимают абсолютные пути. Рабочая директория MCP-клиента и сервера часто различаются, поэтому сервер ничего не угадывает.
decompile-assembly и первый search-source на свежей сборке могут
занимать от десятков секунд до нескольких минут — таймаут 10 минут.
search-source кэширует декомпилированное дерево в
<dir-сборки>/.mcp-dotnet-<имя-сборки>/. Если хочется в другое место —
передай outDir явно. Удаление каталога заставит декомпилировать заново.
ilspycmd запускается дочерним процессом, его stdin не пробрасывается.
Код целевой сборки нигде не исполняется.
MIT。
Decompile the entire assembly into a folder of .cs files (a compilable project). Use this when you want to grep across the whole codebase. Returns the output directory and a flat list of generated files. Heavy - prefer list-types + decompile-type for targeted lookups.
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute path to the assembly. | |
| outDir | Yes | Absolute path where the decompiled project tree should be written. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description discloses that the tool is 'Heavy' (resource-intensive) and returns an output directory and flat list of files. It implies writing to disk but does not specify overwrite behavior or permissions needed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, all essential: purpose, use case, return info, and caveat. Front-loaded and concise with no redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with two simple parameters and no output schema, the description covers the return format ('output directory and flat list of generated files') and hints at the output being a compilable project, making it complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so baseline is 3. The description does not add meaning beyond the schema's parameter descriptions, which are already clear.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb 'decompile' and the resource 'entire assembly into .cs files', and differentiates from sibling tools by specifying that it is for grepping across the whole codebase and that alternatives are better for targeted lookups.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly states when to use ('when you want to grep across the whole codebase') and when not ('prefer list-types + decompile-type for targeted lookups'), providing clear guidance for tool selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Decompile a single fully-qualified type into C# source. Pass the fully qualified name as printed by list-types (e.g. 'Acme.Bot.LicenseManager').
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute path to the assembly. | |
| type | Yes | Fully-qualified type name to decompile. | |
| languageVersion | No | C# language version. Default: Latest. Useful values: CSharp7_3, CSharp10_0, Latest. | |
| includeIl | No | Append IL alongside the C# (ilspycmd -il). Default: false. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so description must carry the full burden. It only states the basic action and parameter format, but omits information about output, errors, permissions, or side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, no redundancy, action-first structure provides maximum information with minimal text.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Adequately describes the tool's core function and input requirements, but lacks details about output format, error handling, and usage context relative to siblings.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions cover all parameters (100% coverage), and the description adds value by specifying that the type name should come from list-types, which clarifies the expected format beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Clearly states 'Decompile a single fully-qualified type into C# source', which is a specific verb-resource combination. Distinguishes from sibling 'decompile-assembly' by targeting a single type rather than a whole assembly.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides a hint to use the output of list-types for the type name, but does not explicitly say when to use this tool vs alternatives or when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
List declared types in a .NET assembly (classes, interfaces, structs, delegates, enums). Use this first to find candidates before calling decompile-type. Works on .dll, .exe, and .NET 6+ single-file deployments (the embedded core assembly is decompiled directly).
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute path to the assembly. | |
| kinds | No | Comma-separated subset of: c (class), i (interface), s (struct), d (delegate), e (enum). Default: 'c,i,s,d,e'. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Without annotations, the description discloses supported file types and special handling for single-file deployments. It implies read-only operation but does not explicitly state safety or side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, no wasted words. Purpose and usage are front-loaded. Highly concise.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Completely covers the tool's purpose and relationship to sibling. Lacks output format details, but for a list tool with no output schema, this is acceptable.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so baseline is 3. The description adds mapping from letters to full type names but does not provide significant additional meaning beyond the schema descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it lists declared types in a .NET assembly, specifying categories (classes, interfaces, structs, delegates, enums). It distinguishes from sibling 'decompile-type' by advising to use this first.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly says 'Use this first to find candidates before calling decompile-type', providing clear context. Also notes compatibility with .dll, .exe, and .NET 6+ single-file deployments, but does not mention exclusions or alternatives for other siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Decompile the assembly to a temporary directory then grep its C# source for a pattern. Returns the matching files with line snippets. The decompiled tree is preserved on disk for follow-up queries (path returned in 'outDir').
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute path to the assembly. | |
| outDir | No | Optional output directory to reuse; otherwise a temp dir under the assembly's directory is created. | |
| pattern | Yes | JavaScript regex pattern. Case-insensitive flag is implied. | |
| maxMatches | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses that decompilation writes to a temporary directory, preserves the tree on disk for follow-up, and returns the outDir path. It does not mention safety or permissions, but the main behaviors are transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, all informative and front-loaded. The first sentence captures the core action, the second explains output, and the third adds key behavioral detail. No extraneous words.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Despite no output schema, the description explains both return values and disk persistence. It covers the necessary context for an agent to invoke the tool correctly, given the sibling tool set.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is high (75%), but the description adds value by explaining the purpose of outDir (optional reuse, returned path) and the pattern's case-insensitive nature. This provides context beyond the schema definitions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool decompiles an assembly and then greps its C# source for a pattern, distinguishing it from sibling tools like decompile-assembly (decompilation only) and decompile-type (specific type decompilation). It specifies the output (matching files with line snippets) and the preserved disk state.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for searching decompiled code but does not explicitly compare with siblings or state when not to use. It lacks guidance on alternatives or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v0.1.0decompile-assemblydecompile-typelist-typessearch-sourceScored across 4 tools
Each tool has a clearly distinct purpose: list-types for browsing, decompile-type for a single type, decompile-assembly for full project, and search-source for pattern matching. No functional overlap.
All tool names follow a consistent lowercase hyphenated verb_noun pattern (e.g., list-types, decompile-assembly), ensuring predictability.
With 4 tools, the server is well-scoped for its domain—covering browsing, targeted decompilation, full decompilation, and source search without unnecessary redundancy.
The set covers core decompilation workflows (list, decompile single, decompile all, search). A minor gap exists for decompiling specific members without the full type, but the overall surface is sufficient for typical use.
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