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Crush can use Language Server Protocol (LSP) servers for additional context to help inform its decisions, just like your code editor does. LSPs provide Crush with:
  • Code intelligence - Type information, definitions, references
  • Diagnostics - Errors, warnings, and code quality issues
  • Navigation - Jump to definitions, find references
  • Contextual understanding - Better comprehension of your codebase structure

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How It Works

When working with code, Crush can query LSP servers to:
  1. Get diagnostic information about files
  2. Find references to functions, types, and variables
  3. Navigate code structure and relationships
  4. Understand type information and signatures
This additional context helps Crush make better decisions when editing, refactoring, or analyzing code.

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Configuration

Configure LSP servers in your crush.json file: 
{
  "$schema": "https://charm.land/crush.json",
  "lsp": {
    "go": {
      "command": "gopls",
      "env": {
        "GOTOOLCHAIN": "go1.24.5"
      }
    },
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"]
    },
    "nix": {
      "command": "nil"
    }
  }
}

​
Configuration Options

Each LSP server configuration supports these fields:

​
command

Type: string The executable command for the LSP server. 
{
  "lsp": {
    "go": {
      "command": "gopls"
    }
  }
}

​
args

Type: string[] Command-line arguments to pass to the LSP server. 
{
  "lsp": {
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"]
    }
  }
}

​
env

Type: object Environment variables to set for the LSP server process. 
{
  "lsp": {
    "go": {
      "command": "gopls",
      "env": {
        "GOTOOLCHAIN": "go1.24.5",
        "GOOS": "linux"
      }
    }
  }
}

​
disabled

Type: boolean
Default: false Disable a specific LSP server without removing its configuration. 
{
  "lsp": {
    "go": {
      "command": "gopls",
      "disabled": true
    }
  }
}

​
filetypes

Type: string[] File extensions this LSP server handles. 
{
  "lsp": {
    "rust": {
      "command": "rust-analyzer",
      "filetypes": ["rs", "toml"]
    }
  }
}

​
root_markers

Type: string[] Files or directories that indicate the project root. 
{
  "lsp": {
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"],
      "root_markers": ["package.json", "tsconfig.json"]
    }
  }
}

​
options

Type: object LSP server-specific settings passed during initialization. 
{
  "lsp": {
    "gopls": {
      "command": "gopls",
      "options": {
        "gofumpt": true,
        "staticcheck": true,
        "analyses": {
          "nilness": true,
          "unusedparams": true
        }
      }
    }
  }
}

​
init_options

Type: object Initialization options passed during the LSP initialize request.

​
timeout

Type: integer
Default: 30 Timeout in seconds for LSP server initialization. 
{
  "lsp": {
    "go": {
      "command": "gopls",
      "timeout": 60
    }
  }
}

​
Example Configurations

​
Go (gopls)

Advanced configuration with gopls options: 
{
  "$schema": "https://charm.land/crush.json",
  "lsp": {
    "gopls": {
      "command": "gopls",
      "options": {
        "gofumpt": true,
        "codelenses": {
          "gc_details": true,
          "generate": true,
          "test": true,
          "tidy": true
        },
        "hints": {
          "assignVariableTypes": true,
          "compositeLiteralFields": true,
          "constantValues": true
        },
        "analyses": {
          "nilness": true,
          "unusedparams": true,
          "unusedwrite": true
        },
        "staticcheck": true,
        "directoryFilters": [
          "-.git",
          "-node_modules"
        ]
      }
    }
  }
}

​
TypeScript

{
  "lsp": {
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"],
      "filetypes": ["ts", "tsx", "js", "jsx"],
      "root_markers": ["package.json", "tsconfig.json"]
    }
  }
}

​
Nix

{
  "lsp": {
    "nix": {
      "command": "nil",
      "filetypes": ["nix"],
      "root_markers": ["flake.nix"]
    }
  }
}

​
Rust

{
  "lsp": {
    "rust": {
      "command": "rust-analyzer",
      "filetypes": ["rs"],
      "root_markers": ["Cargo.toml"],
      "options": {
        "cargo": {
          "buildScripts": {
            "enable": true
          }
        }
      }
    }
  }
}

​
Python

{
  "lsp": {
    "python": {
      "command": "pyright-langserver",
      "args": ["--stdio"],
      "filetypes": ["py"],
      "root_markers": ["pyproject.toml", "setup.py"]
    }
  }
}

​
Installing LSP Servers

Before configuring an LSP server, make sure it’s installed: 
# Install gopls
go install golang.org/x/tools/gopls@latest

​
Debugging LSP Issues

Enable LSP debug logging: 
{
  "options": {
    "debug_lsp": true
  }
}
Or use the command-line flag: 
crush --debug-lsp
Logs are written to ./.crush/logs/crush.log in your project directory.

​
Auto LSP Discovery

Crush can automatically discover and configure LSP servers based on root markers in your project: 
{
  "options": {
    "auto_lsp": true
  }
}
Auto LSP discovery is enabled by default. Set to false to disable.

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Next Steps

MCP Servers

Add Model Context Protocol servers

Tools

Learn about Crush’s built-in tools

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