Symbols MCP

Read, inspect and navigate through codebase symbols by connecting to a Language Server

Introduction

By connecting to a Language Server of choice this MCP server makes it easy and efficient for coding agents to explore and navigate the codebase and its dependencies. The server offers a minimal toolset intended to be simple to use and light on the model's context.

Available Tools

• outline: returns an outline of code symbols in a file. Either compact or with a small code snippet

• inspect: returns docs, signature, declaration and implementation locations for a symbol. For local and third-party ones (e.g. npm, NuGet, ... )

• search: returns matching symbols across the codebase

• references: finds all references of a symbol across the codebase

• rename: renames all references of a symbol across the codebase

• diagnostics: returns active diagnostics in a given file

• completion: returns a list of contextual completions at a given location

• logs: returns Language Server own logs for troubleshooting

Installation

Quickstart (run command)

Use the run command to start the MCP server with the desired Language Server command defined inline.

npx -y "@p1va/symbols" run [run options] <lsp-cmd> [lsp args]

See below configurations for the Language Servers tested. Other stdio Language Servers should work too. For simplicity examples follow Claude Code schema.

Pyright

Installation

npm install -g pyright

Verify Installation

pyright-langserver should be available

Configuration

ℹ️ If you'd rather avoid installing pyright globally and are fine with a slower start up, you can substitute pyright-langserver --stdio in the JSON above with npx -y -p pyright pyright-langserver --stdio

Troubleshooting

Virtual Env not found

If the logs tool output includes errors or the diagnostics tool only reports module import errors even when none appear in the IDE these might be signs of Pyright not detecting the virtual environment.

You can update your pyproject.toml to correctly point it to the virtual environment location.

TypeScript Language Server

Installation

npm install -g typescipt-language-server

Verify Installation

typescipt-language-server --version

Configuration

ℹ️ If you'd rather avoid installing typescript-language-server globally and are fine with a slower start up, you can substitute typescript-language-server --stdio in the JSON above with npx -y typescript-language-server --stdio

Troubleshooting

Search: No results

For the search functionality to work the TS Language Server needs to compute the codebase index and keep in memory. This is done by keeping at least one code file open at any time. Use the SYMBOLS_PRELOAD_FILES="src/index.ts variable with paths to a few files.

Roslyn Language Server

Installation

The official C# Language Server is distributed over the VS IDE NuGet feed as a self-contained executable.

To facilitate download and extraction we use the dotnet CLI with a temporary project file named ServerDownload.csproj with the following content:

We then pick the platform identifier matching the machine from this list:

win-x64, win-arm64, linux-x64, linux-arm64, linux-musl-x64, linux-musl-arm64, osx-x64, osx-arm64 or neutral

And finally restore the temporary project to trigger the download of the Language Server.

Adjust both RestorePackagesPath and ServerPath to work on your machine and keep track of the latter.

Verify Installation

To verify the outcome of the installation we run the command below

Configuration

ℹ️ Roslyn Language Server is also provided with the C# Dev Kit extension for VS Code however the launch command is a bit more complicated and changes each time the extension is updated. If wanting to try it i suggest trying the other modality (config init * start) which brings a template for the launch command

Troubleshooting

Search: No Results Found

If search doesn't find results before a file was read for the first time it's possible to warm up by pre-loading a few files from different projects with "SYMBOLS_PRELOAD_FILES": "src/Project/Program.cs"

Linux: Max Number of Inotify Instances Reached

If on Linux LSP logs suggest that the maximum number of inotify per user instances has been reached it's possible to increase it with a value greater than the actual

sudo sysctl fs.inotify.max_user_instances=512

This allows the Language Server to keep monitoring files in the Solution/Project

Additionally JetBrains has more details on this issue

Clang for C/C++

Verify Installation

clangd --help is available

Configuration

Troubleshooting

General Errors

Ensure either compile_commands.json is found in the working directory or provide its directory path with --compile-commands-dir=path/to/dir

Search: No Results Found

Index is generate when the first file is opened. To warm up is possible to pre load and keep a one or more files opened by providing a list in SYMBOLS_PRELOAD_FILES

Gopls

Installation

Verify Installation

Configuration

Rust-analyzer

Installation

Verify Installation

Configuration

Eclipse JDT Language Server

Installation

Follow installation instructions on the Project's GitHub README

Verify Installation

Configuration

Auto-detection (config & start commands)

If you prefer to keep your MCP config minimal and portable, it's possible to move Language Server definitions out to a dedicated file and have the MCP server read from there and auto-detect which Language Server to launch depending on the codebase.

Initialize Config

User-wide

To create a user-wide config file run the following command

npx -y "@p1va/symbols@latest" config init --global

This will create a configuration file to be found at:

• On Linux: ~/.config/symbols-nodejs/language-servers.yaml

• On MacOS: ~/Library/Preferences/symbols-nodejs/language-servers.yaml

• On Windows: %APPDATA%\symbols-nodejs\Config\language-servers.yaml

Workspace (Defaults to Current Directory)

To create a workspace config file run this instead

npx -y "@p1va/symbols@latest" config init -w path/to/workspace

• Will initialize path/to/workspace/language-servers.yaml

npx -y "@p1va/symbols@latest" config init

• Will initialize ./language-servers.yaml

Tweak Config

Use your editor (here i use code) to tweak the generated config file and comment, uncomment or add new language servers.

code $(npx -y @p1va/symbols config path)

Show Active Config

Finally run the command in your workspace (e.g. where you launch Claude Code) to see that the changes are being applied

npx -y @p1va/symbols config show

npx -y @p1va/symbols config show -w path/to/workspace

npx -y @p1va/symbols config show -c path/to/config.yaml

Update your MCP configuration with this MCP server. The first Language Server having workspace_files matching any of the files seen at the root of the workspace will be launched

Development

• pnpm lint outputs the lint violations

• pnpm lint:fix attempts to fix lint violations

• pnpm format formats the codebase

• pnpm dev starts in development mode

• pnpm build runs the linter and build

• pnpm start starts the built artifacts

• pnpm test:unit runs the unit tests

• pnpm test:integration:{language id} runs the integration tests for a given language