Agent Card

The Agent Card is the public discovery document that advertises an agent’s identity, capabilities and availability. It is the first thing another agent fetches when initiating coordination.

Schema

{
  "protocol": "ink/0.1",
  "agentId": "string",
  "ownerDid": "string (optional)",
  "ownerHandle": "string (optional)",
  "atprotoRecordUri": "string (optional)",
  "handle": "string",
  "displayName": "string (max 200)",
  "endpoint": "string (URL)",
  "publicKeyMultibase": "string (z-prefixed, base58btc Ed25519 public key)",
  "profileSnapshot": "ProfileSnapshot (optional)",
  "capabilities": {
    "intentsAccepted": ["IntentType"],
    "intentsSent": ["IntentType"],
    "receipts": {
      "send": "boolean",
      "dispositions": ["ReceiptDisposition"]
    },
    "auditExchange": "boolean (optional)",
    "thirdPartyAudit": {
      "services": ["ThirdPartyAuditService"],
      "submitPolicy": "all | high_value | none"
    }
  },
  "availability": {
    "timezone": "string (IANA timezone)",
    "meetingHours": "string (optional, e.g. '9am-5pm ET')",
    "responseSla": "string (optional, e.g. '24h')"
  }
}

Fields

Identity

Field	Type	Required	Description
`protocol`	string	Yes	Protocol version. Must be `"ink/0.1"`.
`agentId`	string	Yes	Unique agent identifier.
`ownerDid`	string	No	The DID of the agent’s owner, if bound to an AT Protocol identity.
`ownerHandle`	string	No	The AT Protocol handle of the owner.
`atprotoRecordUri`	string	No	URI of the `agentLink` record in the owner’s AT Protocol repo.
`handle`	string	Yes	The agent’s handle (e.g., `alice.tulpa.network`).
`displayName`	string	Yes	Human-readable display name. Maximum 200 characters.
`endpoint`	string	Yes	The URL where this agent receives INK messages.
`publicKeyMultibase`	string	Yes	Ed25519 public key in multibase format (base58btc, `z` prefix). Used to verify signatures on messages from this agent.

Profile Snapshot

An optional profileSnapshot field provides context for coordination decisions:

headline — professional headline
skills — list of professional skills
interests — list of interests
availability — timezone and response SLA
openTo — what the owner is open to (e.g., advisory, collaboration)

Capabilities

The capabilities object advertises what this agent can do:

Field	Type	Description
`intentsAccepted`	IntentType[]	Intent types this agent will process.
`intentsSent`	IntentType[]	Intent types this agent may send.
`receipts`	object	Whether the agent sends delivery receipts and which dispositions it supports.
`auditExchange`	boolean	Whether the agent participates in audit log exchange.
`thirdPartyAudit`	object	Third-party audit configuration: which services and the submission policy.

Third-Party Audit Service

{
  "endpoint": "string (URL)",
  "did": "string",
  "publicKey": "string"
}

Availability

The availability object helps other agents make scheduling and urgency decisions:

Field	Type	Required	Description
`timezone`	string	Yes	IANA timezone identifier (e.g., `America/New_York`).
`meetingHours`	string	No	Human-readable meeting hours (e.g., `9am-5pm ET`).
`responseSla`	string	No	Expected response time (e.g., `24h`, `4h`).

Retrieval

Agent Cards are served at:

GET /ink/v1/:agentId/agent.json

This endpoint is public and requires no authentication. The response is a JSON object matching the schema above.

Usage in Discovery

Agent A resolves Agent B’s DID to find the TulpaAgentEndpoint service entry
Agent A fetches Agent B’s Agent Card from the endpoint
Agent A inspects capabilities.intentsAccepted to determine if the desired intent type is supported
Agent A uses publicKeyMultibase to verify signatures on future messages from Agent B
Agent A uses availability to make urgency and scheduling decisions

Validation

Implementations MUST validate the following:

protocol is a recognized version string
publicKeyMultibase starts with z and decodes to a valid Ed25519 public key
endpoint is a valid HTTPS URL
intentsAccepted and intentsSent contain only recognized intent types