MCPClientInstall

Safe, non-destructive editing of MCP desktop-client configuration files in Swift.

MCPClientInstall adds or updates a local MCP server in:

Claude Desktop, Claude Code, and Cursor JSON configuration
Codex TOML configuration

It preserves unrelated settings, refuses ambiguous configuration shapes, handles quoted TOML keys and multiline values, retains existing line endings, and can replace files while preserving metadata and leaving a backup.

Installation

.package(
    url: "https://github.com/adamtheturtle/MCPClientInstall.git",
    from: "0.1.0"
)

Add the MCPClientInstall product to your target.

Usage

import MCPClientInstall

let server = MCPServerSpec(
    name: "my-server",
    command: "/usr/local/bin/my-server",
    arguments: ["--mcp"],
    productName: "My Server"
)

// JSON: Claude Desktop, Claude Code, or Cursor
let root = try MCPClientInstall.existingJSON(at: configURL)
let merged = try addingMCPServer(server, toJSON: root)
let data = try MCPClientInstall.prettyJSONData(from: merged.root)

// TOML: Codex
let existing = try String(contentsOf: configURL, encoding: .utf8)
let updated = try addingMCPServer(server, toCodexTOML: existing)

Writing is deliberately separate from merging, so an application can show a diff or ask for confirmation first:

try MCPClientInstall.writeConfig(
    data,
    to: configURL,
    backupSuffix: server.backupSuffix
)

Safety

MCPClientInstall does not silently replace malformed or structurally incompatible configuration. Its file helper refuses symlinks and special files, retains metadata when replacing an existing file, and keeps the previous contents beside the target.

Applications remain responsible for obtaining user consent and filesystem access. The package has no UI and never searches for or modifies configuration on import.

Requirements

Swift 6.2+
macOS 14+
Linux with a Swift 6.2 toolchain

Documentation

The package includes a DocC catalog and is configured for hosted documentation on Swift Package Index.

License

MIT. See LICENSE.