Struct McpToolConfig 

pub struct McpToolConfig {
    pub transport_type: McpTransportType,
    pub command: Option<String>,
    pub args: Vec<String>,
    pub env: Option<Vec<(String, String)>>,
    pub url: Option<String>,
    pub auth_token: Option<String>,
    pub name: Option<String>,
}

Configuration for a single MCP tool source.

Defines how to connect to an MCP server and use its tools.

Examples

STDIO Transport (npx package)

[[agents.mcp_tools]]
type = "stdio"
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]

STDIO Transport (Python MCP server)

[[agents.mcp_tools]]
type = "stdio"
command = "python"
args = ["-m", "mcp_server_time"]

HTTP Transport

[[agents.mcp_tools]]
type = "http"
url = "http://localhost:3000/mcp"
auth_token = "${MCP_AUTH_TOKEN}"

Fields

transport_type: McpTransportType

Transport type: “stdio” or “http”

command: Option<String>

Command to execute (for stdio transport). Examples: “npx”, “python”, “node”, or path to an executable.

args: Vec<String>

Arguments for the command (for stdio transport).

env: Option<Vec<(String, String)>>

Environment variables for the child process (for stdio transport). Format: [[“KEY”, “VALUE”], [“KEY2”, “VALUE2”]]

url: Option<String>

URL for HTTP transport. Example: “http://localhost:3000/mcp”

auth_token: Option<String>

Authentication token for HTTP transport (optional). Can use environment variable syntax: “${MCP_AUTH_TOKEN}”

name: Option<String>

Optional name for this tool source (for logging/debugging).

Implementations

impl McpToolConfig

pub fn stdio(command: impl Into<String>, args: Vec<String>) -> Self

Create a new STDIO transport configuration.

Arguments

• command - Command to execute (e.g., “npx”, “python”)
• args - Arguments to pass to the command

pub fn npx(package: impl Into<String>, extra_args: Vec<String>) -> Self

Create an npx-based MCP tool configuration.

Arguments

• package - NPM package name (e.g., “@modelcontextprotocol/server-filesystem”)
• extra_args - Additional arguments after the package name

pub fn http(url: impl Into<String>) -> Self

Create an HTTP transport configuration.

Arguments

• url - URL of the MCP server

pub fn with_name(self, name: impl Into<String>) -> Self

Set the name for this tool source.

pub fn with_env(self, env: Vec<(String, String)>) -> Self

Set environment variables for the process.

pub fn with_auth_token(self, token: impl Into<String>) -> Self

Set authentication token for HTTP transport.

pub fn validate(&self) -> Result<(), String>

Validate the configuration based on transport type.

Trait Implementations

impl Clone for McpToolConfig

fn clone(&self) -> McpToolConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for McpToolConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for McpToolConfig

fn default() -> McpToolConfig

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for McpToolConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for McpToolConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.