ClaudeWrapper.McpConfig (ClaudeWrapper v0.7.0)

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Programmatic builder for .mcp.json configuration files.

Builds the JSON structure that the Claude CLI expects for MCP server configuration, then writes it to disk or returns it as a string.

Usage

ClaudeWrapper.McpConfig.new()
|> ClaudeWrapper.McpConfig.add_stdio("my-server", "npx", ["-y", "my-mcp-server"],
  env: %{"API_KEY" => "sk-..."}
)
|> ClaudeWrapper.McpConfig.add_sse("remote", "https://example.com/mcp")
|> ClaudeWrapper.McpConfig.write!("/path/to/project/.mcp.json")

Format

The generated JSON follows the Claude CLI's expected format:

{
  "mcpServers": {
    "server-name": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "server-pkg"],
      "env": {"KEY": "value"}
    }
  }
}

Summary

Types

server()
t()

Functions

add_sse(config, name, url, opts \\ [])

Add an SSE-based MCP server.

add_stdio(config, name, command, args \\ [], opts \\ [])

Add a stdio-based MCP server.

from_map(data)

Parse from a decoded JSON map.

get_server(mcp_config, name)

Get a server definition by name.

new()

Create a new empty MCP config.

read(path)

Read and parse an existing .mcp.json file.

remove(config, name)

Remove a server by name.

server_names(mcp_config)

List server names.

to_json(config)

Encode to the JSON string the CLI expects.

write!(config, path)

Write the config to a file.

Types

server()

@type server() :: %{
  type: String.t(),
  command: String.t() | nil,
  args: [String.t()],
  env: %{required(String.t()) => String.t()},
  url: String.t() | nil
}

t()

@type t() :: %ClaudeWrapper.McpConfig{servers: %{required(String.t()) => server()}}

Functions

add_sse(config, name, url, opts \\ [])

@spec add_sse(t(), String.t(), String.t(), keyword()) :: t()

Add an SSE-based MCP server.

Options

  • :env - Map of environment variables

add_stdio(config, name, command, args \\ [], opts \\ [])

@spec add_stdio(t(), String.t(), String.t(), [String.t()], keyword()) :: t()

Add a stdio-based MCP server.

Options

  • :env - Map of environment variables

from_map(data)

@spec from_map(map()) :: t()

Parse from a decoded JSON map.

get_server(mcp_config, name)

@spec get_server(t(), String.t()) :: server() | nil

Get a server definition by name.

new()

@spec new() :: t()

Create a new empty MCP config.

read(path)

@spec read(String.t()) :: {:ok, t()} | {:error, term()}

Read and parse an existing .mcp.json file.

remove(config, name)

@spec remove(t(), String.t()) :: t()

Remove a server by name.

server_names(mcp_config)

@spec server_names(t()) :: [String.t()]

List server names.

to_json(config)

@spec to_json(t()) :: String.t()

Encode to the JSON string the CLI expects.

write!(config, path)

@spec write!(t(), String.t()) :: :ok

Write the config to a file.