Settings

MCPSettings is the main configuration container for the Arcade Server. All settings classes use Pydantic Settings with environment variable support.

`MCPSettings`

arcade_mcp_server.settings.MCPSettings

Bases: BaseSettings

Main settings container that aggregates all sub-settings.

Env prefix: MCP_

Field	Type	Description	Default
`debug`	`bool`	Enable debug mode	`False`
`server`	`ServerSettings`	Server identification settings	`ServerSettings()`
`transport`	`TransportSettings`	Transport and session settings	`TransportSettings()`
`middleware`	`MiddlewareSettings`	Middleware behavior settings	`MiddlewareSettings()`
`notification`	`NotificationSettings`	Notification rate limiting settings	`NotificationSettings()`
`arcade`	`ArcadeSettings`	Arcade platform integration settings	`ArcadeSettings()`
`resource_server`	`ResourceServerSettings`	Resource Server (front-door auth) settings	`ResourceServerSettings()`
`tool_environment`	`ToolEnvironmentSettings`	Tool secrets from environment	`ToolEnvironmentSettings()`

Methods

`from_env`

MCPSettings.from_env()  # classmethod

Create settings from environment variables. Automatically loads a .env file from the current working directory if one exists (override=False, so existing environment variables take precedence).

`tool_secrets`

settings.tool_secrets()

Returns a dict[str, Any] of secrets collected from the environment.

`to_dict`

settings.to_dict()

Convert settings to a dictionary (excludes unset fields).

Example

from arcade_mcp_server.settings import (
    MCPSettings,
    MiddlewareSettings,
    ServerSettings,
    TransportSettings,
)

settings = MCPSettings(
    debug=True,
    middleware=MiddlewareSettings(
        enable_logging=True,
        mask_error_details=False,
    ),
    server=ServerSettings(
        name="MyServer",
        title="My MCP Server",
        instructions="Use responsibly",
    ),
)

Sub-settings

`ServerSettings`

arcade_mcp_server.settings.ServerSettings

Bases: BaseSettings | Env prefix: MCP_SERVER_

Field	Type	Description	Default
`name`	`str`	Server name	`'ArcadeMCP'`
`version`	`str`	Server version	`'0.1.0dev'`
`title`	`str \| None`	Server title for display	`'ArcadeMCP'`
`instructions`	`str \| None`	Server instructions sent to clients	`'ArcadeMCP provides access to a wide range of tools and toolkits...'`

`TransportSettings`

arcade_mcp_server.settings.TransportSettings

Bases: BaseSettings | Env prefix: MCP_TRANSPORT_

Field	Type	Description	Default	Range
`session_timeout_seconds`	`int`	Session timeout in seconds	`300`	30-3600
`cleanup_interval_seconds`	`int`	Cleanup interval in seconds	`10`	1—60
`max_sessions`	`int`	Maximum concurrent sessions	`1000`	1—10000
`max_queue_size`	`int`	Maximum queue size per session	`1000`	10—10000

`MiddlewareSettings`

arcade_mcp_server.settings.MiddlewareSettings

Bases: BaseSettings | Env prefix: MCP_MIDDLEWARE_

Field	Type	Description	Default
`enable_logging`	`bool`	Enable the built-in logging middleware	`True`
`log_level`	`str`	Log level for the logging middleware. Validated to be one of `DEBUG`, `INFO`, `WARNING`, `ERROR`, `CRITICAL`.	`'INFO'`
`enable_error_handling`	`bool`	Enable the built-in error handling middleware	`True`
`mask_error_details`	`bool`	Mask detailed error messages in responses (recommended for production)	`False`

`NotificationSettings`

arcade_mcp_server.settings.NotificationSettings

Bases: BaseSettings | Env prefix: MCP_NOTIFICATION_

Field	Type	Description	Default	Range
`rate_limit_per_minute`	`int`	Maximum notifications per minute per client	`60`	1—1000
`default_debounce_ms`	`int`	Default debounce time in milliseconds	`100`	0—10000
`max_queued_notifications`	`int`	Maximum queued notifications per client	`1000`	10—10000

`ArcadeSettings`

arcade_mcp_server.settings.ArcadeSettings

Bases: BaseSettings | Env prefix: ARCADE_

Field	Type	Description	Default
`api_key`	`str \| None`	Arcade API key for tool authorization	`None`
`api_url`	`str`	Arcade API URL	`'https://api.arcade.dev'`
`auth_disabled`	`bool`	Disable authentication	`False`
`server_secret`	`str \| None`	Server secret for worker endpoints. When set, enables worker routes at `/worker/*`. Reads from `ARCADE_WORKER_SECRET` env var.	`None`
`environment`	`str`	Environment mode (`dev` or `prod`)	`'dev'`
`user_id`	`str \| None`	User ID for tool context	`None`

`ResourceServerSettings`

arcade_mcp_server.settings.ResourceServerSettings

Bases: BaseSettings | Env prefix: MCP_RESOURCE_SERVER_

Settings for configuring front-door OAuth 2.0 authentication via the Resource Server pattern.

Field	Type	Description	Default
`canonical_url`	`str \| None`	Canonical URL of this MCP server (for example, `https://mcp.example.com/mcp`)	`None`
`authorization_servers`	`list[dict] \| None`	JSON array of authorization server configurations. Each entry must have `authorization_server_url`, `issuer`, `jwks_uri`, and optionally `algorithm` (default `RS256`), `expected_audiences`, and `validation_options`.	`None`

`ToolEnvironmentSettings`

arcade_mcp_server.settings.ToolEnvironmentSettings

Bases: BaseSettings

Collects environment variables as secrets. Every environment variable that is not prefixed with MCP_ or _ is added to the tool environment and made available as a tool secret in the ToolContext.

Also loads variables from a .env file in the current working directory.

Field	Type	Description	Default
`tool_environment`	`dict[str, Any]`	Collected tool secrets from environment	`{}` (auto-populated)

Environment variable reference

Here is a summary of key environment variables:

Variable	Settings class	Description
`MCP_DEBUG`	`MCPSettings`	Enable debug mode (`true`/`false`)
`MCP_SERVER_NAME`	`ServerSettings`	Server name
`MCP_SERVER_VERSION`	`ServerSettings`	Server version
`MCP_SERVER_TITLE`	`ServerSettings`	Server display title
`MCP_SERVER_INSTRUCTIONS`	`ServerSettings`	Server instructions
`MCP_TRANSPORT_SESSION_TIMEOUT_SECONDS`	`TransportSettings`	Session timeout
`MCP_TRANSPORT_MAX_SESSIONS`	`TransportSettings`	Max concurrent sessions
`MCP_MIDDLEWARE_ENABLE_LOGGING`	`MiddlewareSettings`	Enable logging middleware
`MCP_MIDDLEWARE_LOG_LEVEL`	`MiddlewareSettings`	Middleware log level
`MCP_MIDDLEWARE_MASK_ERROR_DETAILS`	`MiddlewareSettings`	Mask error details
`ARCADE_API_KEY`	`ArcadeSettings`	Arcade API key
`ARCADE_API_URL`	`ArcadeSettings`	Arcade API URL
`ARCADE_AUTH_DISABLED`	`ArcadeSettings`	Disable authentication
`ARCADE_USER_ID`	`ArcadeSettings`	User ID
`ARCADE_WORKER_SECRET`	`ArcadeSettings`	Worker secret (enables worker routes)

Additionally, MCPApp.run() checks these environment variable overrides at runtime:

Variable	Description
`ARCADE_SERVER_TRANSPORT`	Override transport (`"stdio"` or `"http"`)
`ARCADE_SERVER_HOST`	Override host (HTTP only)
`ARCADE_SERVER_PORT`	Override port (HTTP only)
`ARCADE_SERVER_RELOAD`	Override reload (`"0"` or `"1"`, HTTP only)

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