Creating an Agent

An agent is the fundamental identity in JACS: an entity with signing keys that can create, sign, and verify documents.

What is an Agent?

A JACS agent is:

• A stable UUID identity
• A holder of cryptographic signing keys
• A self-signed identity document
• An optional DNS-verifiable identity

Capabilities for A2A interoperability live in A2A Agent Cards. The JACS agent document stays focused on identity and signing metadata.

Creating Your First Agent

jacs init

This creates:

• Configuration file
• Cryptographic key pair
• Initial agent document

Manual Creation

jacs config create
jacs agent create --create-keys true

Custom Agent Definition

Create an agent definition file:

{
  "$schema": "https://hai.ai/schemas/agent/v1/agent.schema.json",
  "jacsAgentType": "ai",
  "jacsAgentDomain": "myagent.example.com",
  "name": "Content Creation Agent",
  "description": "AI agent specialized in content creation"
}

Then create the agent:

jacs agent create --create-keys true -f my-agent.json

Agent Types

Cryptographic Keys

JACS supports:

Configure the default algorithm in jacs.config.json:

{
  "jacs_agent_key_algorithm": "ring-Ed25519"
}

Or with an environment variable:

JACS_AGENT_KEY_ALGORITHM=ring-Ed25519 jacs agent create --create-keys true

Verifying Agents

jacs agent verify
jacs agent verify -a ./path/to/agent.json
jacs agent verify --require-dns
jacs agent verify --require-strict-dns

Agent Document Structure

{
  "$schema": "https://hai.ai/schemas/agent/v1/agent.schema.json",
  "jacsId": "550e8400-e29b-41d4-a716-446655440000",
  "jacsVersion": "123e4567-e89b-12d3-a456-426614174000",
  "jacsVersionDate": "2024-01-15T10:30:00Z",
  "jacsOriginalVersion": "123e4567-e89b-12d3-a456-426614174000",
  "jacsOriginalDate": "2024-01-15T10:30:00Z",
  "jacsType": "agent",
  "jacsLevel": "config",
  "jacsAgentType": "ai",
  "jacsAgentDomain": "myagent.example.com",
  "name": "Content Creation Agent",
  "description": "AI agent for content generation",
  "jacsSha256": "hash-of-document",
  "jacsSignature": {
    "agentID": "550e8400-e29b-41d4-a716-446655440000",
    "agentVersion": "123e4567-e89b-12d3-a456-426614174000",
    "signature": "base64-encoded-signature",
    "signingAlgorithm": "ring-Ed25519",
    "publicKeyHash": "hash-of-public-key",
    "date": "2024-01-15T10:30:00Z",
    "fields": ["jacsId", "jacsVersion", "jacsAgentType", "jacsAgentDomain", "name"]
  }
}

Best Practices

1. Protect private keys.
2. Prefer strong signing algorithms.
3. Enable DNS verification for production agents.
4. Keep A2A capabilities in the A2A Agent Card.
5. Track agent document versions.

Next Steps

• Working with Documents
• Agreements
• DNS Verification