> ## Documentation Index
> Fetch the complete documentation index at: https://gofastmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.
# mcp_config
# `fastmcp.mcp_config`
Canonical MCP Configuration Format.
This module defines the standard configuration format for Model Context Protocol (MCP) servers.
It provides a client-agnostic, extensible format that can be used across all MCP implementations.
The configuration format supports both stdio and remote (HTTP/SSE) transports, with comprehensive
field definitions for server metadata, authentication, and execution parameters.
Example configuration:
```json theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
{
"mcpServers": {
"my-server": {
"command": "npx",
"args": ["-y", "@my/mcp-server"],
"env": {"API_KEY": "secret"},
"timeout": 30000,
"description": "My MCP server"
}
}
}
```
## Functions
### `infer_transport_type_from_url`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
infer_transport_type_from_url(url: str | AnyUrl) -> Literal['http', 'sse']
```
Infer the appropriate transport type from the given URL.
### `update_config_file`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
update_config_file(file_path: Path, server_name: str, server_config: CanonicalMCPServerTypes) -> None
```
Update an MCP configuration file from a server object, preserving existing fields.
This is used for updating the mcpServer configurations of third-party tools so we do not
worry about transforming server objects here.
## Classes
### `StdioMCPServer`
MCP server configuration for stdio transport.
This is the canonical configuration format for MCP servers using stdio transport.
**Methods:**
#### `to_transport`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
to_transport(self) -> StdioTransport
```
### `TransformingStdioMCPServer`
A Stdio server with tool transforms.
### `RemoteMCPServer`
MCP server configuration for HTTP/SSE transport.
This is the canonical configuration format for MCP servers using remote transports.
**Methods:**
#### `to_transport`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
to_transport(self) -> StreamableHttpTransport | SSETransport
```
### `TransformingRemoteMCPServer`
A Remote server with tool transforms.
### `MCPConfig`
A configuration object for MCP Servers that conforms to the canonical MCP configuration format
while adding additional fields for enabling FastMCP-specific features like tool transformations
and filtering by tags.
For an MCPConfig that is strictly canonical, see the `CanonicalMCPConfig` class.
**Methods:**
#### `wrap_servers_at_root`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
wrap_servers_at_root(cls, values: dict[str, Any]) -> dict[str, Any]
```
If there's no mcpServers key but there are server configs at root, wrap them.
#### `add_server`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
add_server(self, name: str, server: MCPServerTypes) -> None
```
Add or update a server in the configuration.
#### `from_dict`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
from_dict(cls, config: dict[str, Any]) -> Self
```
Parse MCP configuration from dictionary format.
#### `to_dict`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
to_dict(self) -> dict[str, Any]
```
Convert MCPConfig to dictionary format, preserving all fields.
#### `write_to_file`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
write_to_file(self, file_path: Path) -> None
```
Write configuration to JSON file.
#### `from_file`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
from_file(cls, file_path: Path) -> Self
```
Load configuration from JSON file.
### `CanonicalMCPConfig`
Canonical MCP configuration format.
This defines the standard configuration format for Model Context Protocol servers.
The format is designed to be client-agnostic and extensible for future use cases.
**Methods:**
#### `add_server`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
add_server(self, name: str, server: CanonicalMCPServerTypes) -> None
```
Add or update a server in the configuration.
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