# DecompilerServer > A powerful MCP (Model Context Protocol) server for decompiling and analyzing .NET assemblies, with specialized support for Unity's Assembly-CSharp.dll files. DecompilerServer provides comprehensive decompilation, search, and code analysis capabilities through a rich set of tools and APIs. - **Type:** MCP server - **Install:** `agentstack add mcp-pardeike-decompilerserver` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [pardeike](https://agentstack.voostack.com/s/pardeike) - **Installs:** 0 - **Category:** [Search](https://agentstack.voostack.com/c/search) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [pardeike](https://github.com/pardeike) - **Source:** https://github.com/pardeike/DecompilerServer ## Install ```sh agentstack add mcp-pardeike-decompilerserver ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # DecompilerServer DecompilerServer is an MCP server that decompiles and analyzes .NET assemblies. You connect it to your AI coding tool (Claude Desktop, Cursor, VS Code, Codex, etc.) and it lets the AI read, search, and compare .NET code — even across different versions of an assembly. This is a particularly strong LLM use case because so much real-world .NET behavior lives in binaries the model cannot inspect on its own: third-party libraries, game assemblies, internal builds, and older releases. By giving the model direct decompiler-backed access to those assemblies, you turn "I only see the source in this repo" into "I can inspect the actual code that runs", which makes reverse engineering, migration work, debugging, and version-to-version analysis much more effective. Common use cases: general .NET assembly inspection, Unity `Assembly-CSharp.dll` workflows, and multi-version browsing such as RimWorld mod porting. > **Already familiar with .NET and MCP?** Skip to [Advanced Guide](#advanced-guide) for build-from-source instructions, full tool reference, and development details. --- ## Quick Start This section helps you install DecompilerServer and connect it to your MCP client in a few steps. ### What You Need **[.NET 10 runtime](https://dotnet.microsoft.com/download/dotnet/10.0)** — the prebuilt release binaries depend on it. Download and install the runtime for your platform before continuing. ### Step 1 — Download Go to the [latest release](https://github.com/pardeike/DecompilerServer/releases/latest) and download the archive for your platform: | Platform | File | |---|---| | Windows (x64) | `decompilerserver-v…-win-x64.zip` | | macOS (Apple Silicon) | `decompilerserver-v…-osx-arm64.tar.gz` | | macOS (Intel) | `decompilerserver-v…-osx-x64.tar.gz` | | Linux (x64) | `decompilerserver-v…-linux-x64.tar.gz` | | Linux (ARM64) | `decompilerserver-v…-linux-arm64.tar.gz` | Extract the archive to a folder you can remember (for example `~/tools/decompiler-server`). Extract commands **Windows** (PowerShell): ```powershell Expand-Archive decompilerserver-v*-win-x64.zip -DestinationPath "$HOME\tools\decompiler-server" ``` **macOS / Linux**: ```bash mkdir -p ~/tools/decompiler-server tar -xzf decompilerserver-v*-*.tar.gz -C ~/tools/decompiler-server --strip-components=1 ``` ### Step 2 — Configure Your MCP Client Add DecompilerServer to your MCP client configuration. Replace the path below with the actual location where you extracted the files. Claude Desktop Edit the Claude Desktop config file: - **macOS**: `~/Library/Application Support/Claude/claude_desktop_config.json` - **Windows**: `%APPDATA%\Claude\claude_desktop_config.json` ```json { "mcpServers": { "decompiler": { "command": "/absolute/path/to/DecompilerServer" } } } ``` On Windows, use the `.exe` extension and escaped backslashes: ```json { "mcpServers": { "decompiler": { "command": "C:\\tools\\decompiler-server\\DecompilerServer.exe" } } } ``` Restart Claude Desktop after saving. Cursor Open Cursor Settings → MCP and add a new server, or edit `.cursor/mcp.json` in your project root: ```json { "mcpServers": { "decompiler": { "command": "/absolute/path/to/DecompilerServer" } } } ``` On Windows, use the `.exe` extension and escaped backslashes. VS Code (GitHub Copilot) Add an entry to your `.vscode/mcp.json` (or workspace settings): ```json { "servers": { "decompiler": { "type": "stdio", "command": "/absolute/path/to/DecompilerServer" } } } ``` On Windows, use the `.exe` extension and escaped backslashes. Codex Add an entry to `~/.codex/config.toml`: ```toml [mcp_servers.decompiler] command = "/absolute/path/to/DecompilerServer" ``` If you run a framework-dependent build instead of the native app host, configure Codex like this: ```toml [mcp_servers.decompiler] command = "dotnet" args = ["/absolute/path/to/DecompilerServer/bin/Release/net10.0/DecompilerServer.dll"] ``` On Windows, use the `.exe` extension and escaped backslashes. ### Step 3 — Use It Once connected, ask your AI assistant to load and explore assemblies. For example: > "Load the assembly at `/path/to/MyLibrary.dll` and search for types that contain `Controller`." The assistant will use DecompilerServer tools automatically. It can load assemblies, search types, decompile source, compare versions, and more. See the [Workflow Reference](#workflow-reference) for the full list of operations. ### Troubleshooting | Problem | Solution | |---|---| | **"command not found"** or the server does not start | Verify the path in your MCP config points to the correct executable. On macOS/Linux, ensure the file is executable: `chmod +x DecompilerServer`. | | **"You must install .NET to run this application"** | Install the [.NET 10 runtime](https://dotnet.microsoft.com/download/dotnet/10.0). The prebuilt binaries do not include the runtime. | | **macOS blocks the binary** ("unidentified developer") | Open System Settings → Privacy & Security and allow the application, or run: `xattr -d com.apple.quarantine DecompilerServer`. | | **Server starts but the AI does not use it** | Check that the MCP client has the server enabled. In Claude Desktop, restart the app. In Cursor, check the MCP panel. In VS Code, reload the window. | | **Assembly fails to load** | Confirm the `.dll` path is correct and that the assembly is a managed .NET assembly (not a native library). | --- ## Advanced Guide This section covers building from source, the full set of MCP launch options, the complete tool workflow, and contributor information. ### Highlights - Load assemblies directly with `assemblyPath` or use Unity-friendly `gameDir` loading. - Keep multiple assemblies loaded at once under aliases such as `rw14`, `rw15`, and `rw16`. - Use `memberId` follow-up tools without repeatedly resupplying the alias; routing uses the member ID's MVID. - Compare aliases structurally with `compare_contexts`, then drill into types or members with `compare_symbols`. - Diff individual method bodies with `compare_symbols(..., compareMode: "body")`. - Decompiled non-type member source is returned as a member-scoped snippet rather than a whole containing type. ### Requirements - .NET 10 runtime for release assets or built output - .NET 10 SDK if you want to build from source ### Build from Source ```bash git clone https://github.com/pardeike/DecompilerServer.git cd DecompilerServer dotnet build DecompilerServer.sln -c Release dotnet run --project DecompilerServer.csproj -c Release ``` ### MCP Client Launch Options **Framework-dependent build output** (requires `dotnet` on PATH): ```text command: dotnet args: - /absolute/path/to/DecompilerServer/bin/Release/net10.0/DecompilerServer.dll ``` **Native app host from `dotnet build`:** - macOS/Linux: `/absolute/path/to/DecompilerServer/bin/Release/net10.0/DecompilerServer` - Windows: `C:\\absolute\\path\\to\\DecompilerServer\\bin\\Release\\net10.0\\DecompilerServer.exe` **Native app host from `dotnet publish`:** - macOS/Linux: `/absolute/path/to/DecompilerServer/bin/Release/net10.0/publish/DecompilerServer` - Windows: `C:\\absolute\\path\\to\\DecompilerServer\\bin\\Release\\net10.0\\publish\\DecompilerServer.exe` Release assets are packaged as framework-dependent single-file executables and still require the .NET 10 runtime. ### Trusted Local Codex Install If Codex for Mac warns about the downloaded MCP executable, install the server from source instead of running a quarantined release artifact: ```bash ./scripts/install-codex-mcp.sh ``` The installer publishes an `osx-arm64` Release build to `~/.codex/mcp-servers/decompiler/DecompilerServer`, removes quarantine metadata, signs the executable with the best local code-signing identity available, updates Codex's global `decompiler` MCP entry to launch that installed copy, installs the bundled `decompiler-mcp` skill into `~/.codex/skills/decompiler-mcp`, and maintains a managed DecompilerServer pointer block in `~/.codex/AGENTS.md`. For local Codex stdio use, this avoids Safari/Gatekeeper quarantine state on downloaded binaries. For distributable Gatekeeper acceptance, sign with a `Developer ID Application` identity and notarize the archive before installation. ### Workflow Reference **Load one or more assemblies:** ```text load_assembly({ "assemblyPath": "/path/to/rw14/Assembly-CSharp.dll", "contextAlias": "rw14" }) load_assembly({ "gameDir": "/path/to/rw16", "assemblyFile": "Assembly-CSharp.dll", "contextAlias": "rw16" }) ``` **Inspect loaded aliases:** ```text list_contexts({}) status({}) get_server_stats({ "contextAlias": "rw16" }) ``` **Search and decompile:** ```text search_symbols({ "query": "Pawn.Kill", "limit": 10, "contextAlias": "rw16" }) search_types({ "query": "Pawn", "limit": 10, "contextAlias": "rw16" }) list_members({ "typeId": "", "mode": "signatures" }) get_decompiled_source({ "memberId": "" }) ``` Once you have a `memberId`, follow-up tools normally route to the correct loaded assembly automatically. For foreign-code exploration, prefer this path before falling back to shell tools: 1. Load the assembly with `load_assembly` and verify the active alias with `list_contexts` or `status`. 2. Start broad with `search_symbols` when you have a fragment; use `resolve_member_id` first when you have a fully-qualified or XML-doc-like guess such as `Namespace.Type.Member` or `M:Namespace.Type.Member`. 3. Use `list_members` or `get_members_of_type` on the resolved type before guessing method IDs. 4. Fetch code with `get_decompiled_source`, `get_source_slice`, or `plan_chunking`. 5. Move outward with `find_callers`, `find_usages`, `find_callees`, `get_il`, or compare tools. `find_callees` returns callee-focused `targetMemberId`, `symbol`, `opcode`, `offset`, and `resolution` fields; external calls are explicit instead of pretending to be canonical local IDs. 6. Use `get_server_stats` when you need cache/index/performance diagnostics for one alias; `status` is the cheaper current-alias overview. If a guessed member does not exist, member-based tools return structured error hints with likely candidates and concrete next tool calls. `search_symbols` also degrades gracefully for `Type.MissingMember`: if the type resolves but the member does not, it returns the type, its direct members, and a diagnostic instead of an empty success. **Compare aliases:** ```text compare_contexts({ "leftContextAlias": "rw14", "rightContextAlias": "rw16", "namespaceFilter": "Verse", "deep": true }) compare_symbols({ "leftContextAlias": "rw14", "rightContextAlias": "rw16", "symbol": "Verse.Root_Play", "symbolKind": "type" }) compare_symbols({ "leftContextAlias": "rw14", "rightContextAlias": "rw16", "symbol": "Verse.Pawn:Kill", "symbolKind": "method", "compareMode": "body" }) ``` ### Development ```bash dotnet format DecompilerServer.sln dotnet test -c Release ``` After restore/build has already completed, `dotnet test -c Release --no-restore` is the faster repeat check. ### Agent Skill The repo includes a portable skill at [skills/decompiler-mcp/SKILL.md](skills/decompiler-mcp/SKILL.md). For Codex, `./scripts/install-codex-mcp.sh` installs that skill and keeps the global `AGENTS.md` pointer up to date. For Claude or another skill-aware assistant, copy the skill folder manually to bias agents toward the intended DecompilerServer workflow and away from premature shell fallbacks. ### Releasing The GitHub `Release` workflow is triggered by pushing a tag that starts with `v` and matches the project version in `DecompilerServer.csproj`. For example, if the project version is `1.3.6`: ```bash git tag -a v1.3.6 -m "Release v1.3.6" git push origin v1.3.6 ``` ### Documentation - [README.md](README.md): user-facing overview and quick start - [ARCHITECTURE.md](ARCHITECTURE.md): durable technical reference (implementation details, routing, compare semantics, testing) - [TODO.md](TODO.md): backlog and future work If you are changing implementation details, tool-routing behavior, compare semantics, or test patterns, update [ARCHITECTURE.md](ARCHITECTURE.md) rather than creating a new standalone guide. ## Source & license This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [pardeike](https://github.com/pardeike) - **Source:** [pardeike/DecompilerServer](https://github.com/pardeike/DecompilerServer) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/mcp-pardeike-decompilerserver - Seller: https://agentstack.voostack.com/s/pardeike - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.