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

# agent.init()

> Creates or reuses an Ed25519 keypair, registers the agent, and writes credentials to .env

## Overview

The `agent.init()` method initializes a new Vestauth agent by creating (or reusing) an Ed25519 keypair, registering it with the Vestauth API, and persisting the credentials to your `.env` file.

## Signature

```typescript theme={null}
agent.init(): Promise<{
  AGENT_PUBLIC_JWK: PublicJwk
  AGENT_UID: string
  path: string
  isNew: boolean
}>
```

## Parameters

This method takes no parameters. It automatically reads existing credentials from `.env` if available.

## Return Value

Returns a Promise that resolves to an object with the following properties:

<ResponseField name="AGENT_PUBLIC_JWK" type="PublicJwk" required>
  The public JWK (JSON Web Key) for the agent. This is an Ed25519 OKP key.

  ```typescript theme={null}
  {
    kty: 'OKP',
    crv: 'Ed25519',
    x: string,
    kid?: string
  }
  ```
</ResponseField>

<ResponseField name="AGENT_UID" type="string" required>
  The unique identifier (UID) assigned to this agent by Vestauth.
</ResponseField>

<ResponseField name="path" type="string" required>
  The path to the `.env` file where credentials were written (defaults to `.env`).
</ResponseField>

<ResponseField name="isNew" type="boolean" required>
  Indicates whether this is a newly created agent (`true`) or an existing agent that was re-registered (`false`).
</ResponseField>

## Environment Variables

After calling `init()`, the following variables are written to your `.env` file:

* `AGENT_UID` - The agent's unique identifier
* `AGENT_PUBLIC_JWK` - The agent's public key (JSON string)
* `AGENT_PRIVATE_JWK` - The agent's private key (JSON string)
* `AGENT_HOSTNAME` - The Vestauth API hostname (only if non-default)

## Example

```javascript theme={null}
import { agent } from 'vestauth'

// Initialize a new agent
const result = await agent.init()

console.log('Agent UID:', result.AGENT_UID)
console.log('Public Key:', result.AGENT_PUBLIC_JWK)
console.log('Is new agent:', result.isNew)
console.log('Credentials saved to:', result.path)
```

## Example Output

```javascript theme={null}
{
  AGENT_UID: 'abc123def456',
  AGENT_PUBLIC_JWK: {
    kty: 'OKP',
    crv: 'Ed25519',
    x: 'MYf21IkWEi6dXOtzUdbll3SMCaFiSFi4KgqktFZinCE',
    kid: 'rBE7_zLOVYk4oYEdI-01qpXHWNMyZYD-4LEf6HiyZ9Q'
  },
  path: '.env',
  isNew: true
}
```

## Behavior

1. **Keypair Creation**: If `AGENT_PRIVATE_JWK` exists in `.env`, it will be reused. Otherwise, a new Ed25519 keypair is generated.
2. **Registration**: The agent is registered with the Vestauth API at `https://api.vestauth.com` (or a custom hostname if configured).
3. **Persistence**: All credentials are written to `.env` using `dotenvx` for secure storage.
4. **Idempotency**: Safe to call multiple times - will reuse existing keys if found.

## Error Handling

```javascript theme={null}
try {
  const result = await agent.init()
  console.log('Agent initialized:', result.AGENT_UID)
} catch (error) {
  console.error('Failed to initialize agent:', error.message)
}
```

## Related Methods

* [agent.headers()](/api/agent/headers) - Generate signature headers for requests
* [agent.rotate()](/api/agent/rotate) - Rotate the agent's keypair
* [primitives.keypair()](/api/primitives/keypair) - Create a keypair without registration