> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blink.so/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment Variables

> Configure environment variables for your Blink agents, including secrets.

Agent environment variables are configured in the web UI and passed to agent containers at runtime.

## Managing Environment Variables

Configure environment variables through the Blink web UI:

1. Navigate to your agent's settings
2. Go to **Settings** → **Environment Variables**
3. Add, edit, or delete variables as needed

Each variable has:

* **Key** - The variable name (e.g., `ANTHROPIC_API_KEY`)
* **Value** - The variable value
* **Secret** - Whether to mask the value

## Secret Variables

Mark variables as "secret" for sensitive values like API keys and tokens:

* Values are masked as "Hidden" in the UI
* Secret values are never returned in API responses

## System-Reserved Variables

These variables are automatically set by the server and cannot be overridden:

| Variable                                | Description                                    |
| --------------------------------------- | ---------------------------------------------- |
| `ENTRYPOINT`                            | Path to agent entry point (e.g., `./index.ts`) |
| `PORT`                                  | Container external API port (3000)             |
| `BLINK_REQUEST_URL`                     | Base URL for agent to reach Blink API          |
| `BLINK_REQUEST_ID`                      | Request ID from deployment target              |
| `BLINK_DEPLOYMENT_TOKEN`                | Token for OTLP authentication                  |
| `BLINK_USE_STRUCTURED_LOGGING`          | Enables structured logging (`1`)               |
| `INTERNAL_BLINK_API_SERVER_URL`         | Internal API server URL                        |
| `INTERNAL_BLINK_API_SERVER_LISTEN_PORT` | Internal API port (3010)                       |