Environment variables are retrieved first from your .env file, and if not found there, from the [env] section of blaxel.toml. This fallback mechanism allows for two kinds of variables:

  • simple environment variables
  • secrets

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Variables

You can define variables inside your agent or MCP server in the blaxel.toml file at root level of your project. These variables are NOT intended to be use as secrets, but as configuration variables.

blaxel.toml

name = "..."
workspace = "..."
type = "function"

[env]
DEFAULT_CITY = "San Francisco"

You can then use it in your code with the env.DEFAULT_CITY variable.


process.env.DEFAULT_CITY

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Secrets

You can create a file named .env at the root level of your project to store your secrets. The .env file should be added to your .gitignore file to prevent committing these sensitive variables.

MY_SECRET_VARIABLE=mySecretValue

You can then use secrets in your code with the env.MY_SECRET_VARIABLE variable.

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Reserved variables

The following variables are reserved by Blaxel:

PORT: Reserved by the system.

BL_SERVER_PORT : Port of the HTTP server, it need to be set to allow Blaxel platform to configure it

BL_SERVER_HOST : Host of the HTTP server, it need to be set to allow Blaxel platform to configure it

Internal URL for Blaxel platform, to avoid linking multiple instance through the Internet

BL_AGENT_${envVar}_SERVICE_NAME

BL_FUNCTION_${envVar}_SERVICE_NAME

BL_RUN_INTERNAL_HOSTNAME: internal run url

Override URL to link multiple agents and MCP servers together locally

BL_AGENT_${envVar}_URL

BL_FUNCTION_${envVar}_URL

Metadata automatically set by blaxel platform in production

BL_WORKSPACE : workspace name

BL_NAME : name of the function or the agent

BL_TYPE : function or agent

Authentication environment variables

BL_CLIENT_CREDENTIALS : client credentials, used by Blaxel in production with a workspaced service account

BL_API_KEY : can be set in your code to connect with the platform (locally or from a server not on Blaxel platform)

BL_LOG_LEVEL : Log level, default to info, can be set to debug,warn,error

BL_DEBUG_TELEMETRY: Enable telemetry debug mode, will print each interaction with OpenTelemetry

BL_ENABLE_OPENTELEMETRY: Enable OpenTelemetry, it’s set automatically by the platform in production