What is Agent Auth by Vigil?

Agent Auth by Vigil is DID-based identity infrastructure for AI agents. Agents register an Ed25519 keypair, authenticate via cryptographic challenge-response, and receive Verifiable Credentials — register once, authenticate everywhere.

How does AI agent authentication work?

AI agents register a DID identity with an Ed25519 public key. To authenticate, the agent requests a cryptographic challenge nonce, signs it with their private key, and the server verifies the signature. Upon success, the agent receives a Verifiable Credential JWT that can be presented to any trusting site.

Do AI agents need to register?

Yes, agents perform a one-time DID registration by submitting their agent name, model, provider, and purpose. The server generates an Ed25519 keypair and returns the DID, credential, and private key. After that single registration, the agent can authenticate on any site that uses Agent Auth by Vigil — register once, authenticate everywhere.

How do I integrate Agent Auth by Vigil into my website?

Integration is straightforward: (1) agents register a DID identity via POST /v1/identities with their name, model, provider, and purpose, (2) agents authenticate via Ed25519 challenge-response signing, (3) your site verifies the Verifiable Credential JWT that agents present. Full documentation at https://usevigil.dev/docs/

Is Agent Auth by Vigil free?

Agent Auth by Vigil is currently free to use during the beta period. No credit card or payment information is required.

What is the A2A Protocol Agent Card?

The agent.json at /.well-known/agent.json describes Agent Auth by Vigil capabilities in a machine-readable format following the Agent-to-Agent (A2A) protocol, enabling automatic discovery by other AI agents and platforms.

// Agent Sign In

Sign in with your DID.

Verify your DID identity with Agent Auth by Vigil. Follow the steps below to register and sign in.

Register your DID identity

curl -X POST https://auth.usevigil.dev/v1/identities \
  -H "Content-Type: application/json" \
  -d '{
    "agent_name": "your-agent-name",
    "agent_model": "your-model",
    "agent_provider": "your-provider",
    "agent_purpose": "your-purpose"
  }'

Save your credentials

# Response:
{
  "did": "did:key:z6Mk...",
  "credential": "eyJhbGciOiJFZERTQSJ9...",
  "key_fingerprint": "SHA256:...",
  "private_key_jwk": { "kty": "OKP", ... }
}

Sign in below

# Paste the "did" and "credential" from the
# response into the form on this page.

// Sign In

Sign in with your DID.

Register your DID identity

Save your credentials

Sign in below

Authenticate with DID