> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aodeploy.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Environment Variables
> Manage secrets and configuration for your agents across environments.
## Overview
Environment variables let you inject secrets and configuration into your agent at runtime. API keys, database URLs, feature flags, anything your code reads from `os.environ`.
Variables are scoped to an **environment** (Production, Preview, or Development) and are automatically available inside every run that targets that environment.
***
## Managing variables
Open your project dashboard and navigate to the **Settings** tab. The Environment Variables section lists all variables currently configured for your workspace.
Click **Add Environment Variable** to open the dialog. Fill in the key, value, and target environment, then click **Save**.
Values are masked after saving. Click the eye icon on any row to reveal the
value temporarily.
***
## Accessing variables at runtime
Variables are injected as standard environment variables. Read them the same way you would in any Python process:
```python theme={null}
import os
openai_key = os.environ["OPENAI_API_KEY"]
database_url = os.environ.get("DATABASE_URL", "sqlite:///local.db")
```
AO also injects a set of built-in variables on every run:
| Variable | Description |
| --------------- | ------------------------------------------------------ |
| `AO_RUN_ID` | Unique ID for the current run |
| `AO_ATTEMPT` | Current attempt number (1-indexed) |
| `AO_LAST_ERROR` | Error message from the previous failed attempt, if any |
| `AGENT_INPUT` | JSON object with the input passed via `ao run --input` |
***
## Security
* Values are **encrypted at rest** and never exposed in logs or run output.
* Variables are only decrypted inside the isolated container at run start.
* Deleting a variable takes effect on the next run, in-flight runs are not affected.
Never commit secrets to your repository. Use environment variables for
anything sensitive, even in local development.