Agent Contact Card

Agent Contact Card

A simple format for publishing how AI agents can be contacted. Like a vCard, but for agents.

When to Use This Skill

User asks how to let other agents contact their agent User wants to discover how to reach someone else's agent You need to contact another agent on behalf of your user User mentions "agent-card", "agent contact", or agent-to-agent communication

Discovering an Agent Contact Card

Try fetching /.well-known/agent-card on their domain: https://example.com/.well-known/agent-card The file is markdown with YAML frontmatter. Parse the frontmatter for structured channel data, read the prose for routing rules.

Creating an Agent Contact Card

• Create a markdown file with YAML frontmatter:
• ---
• version: "1"
• human_contact: "+1 555 123 4567"
• channels:
• email: "agent@example.com"
• discord: "my-agent#1234"
• webhook:
• url: "https://example.com/agent/incoming"
• method: "POST"
• format: "JSON with 'message' field"
• capabilities:
• - scheduling
• - accepts_ical
• ---
• # My Agent
• If you're a human, call the number above.
• If you're an agent:
• For scheduling requests, use Discord
• For urgent matters, email with "URGENT" in subject
• Response time: within a few hours
• Host this at /.well-known/agent-card on the user's domain.

Required Fields

FieldDescriptionversionSpec version. Currently "1"

Recommended Fields

FieldDescriptionhuman_contactPhone/email for humans to reach the humanchannelsContact channels for agents (see below)

Optional Fields

FieldDescriptionnameDisplay name for this agent configurationlast_updatedISO date when card was last modifiedcapabilitiesWhat this agent can do (e.g., ["scheduling", "accepts_ical"])agentsNamed agents if multiple (see Multi-Agent section)

Channels

Channel names are freeform. Common ones: email - Email address discord - Discord username webhook - HTTP endpoint for structured messages signal - Signal phone number telegram - Telegram username For webhooks, provide details: channels: webhook: url: "https://example.com/agent/incoming" method: "POST" auth: "Bearer token in Authorization header" format: "JSON with 'message' and 'from' fields"

Multi-Agent Setups

List multiple specialized agents: agents: - name: "Calendar Agent" handles: ["scheduling", "availability"] channel: discord id: "cal-agent#1234" - name: "Support Agent" handles: ["technical questions"] channel: webhook id: "https://example.com/support" The markdown body should explain routing between them.

Privacy Tiers

Different URLs for different access levels: TierURL PatternAccessPublic/.well-known/agent-cardAnyoneNamed/.well-known/agent-card/{name}Know the namePrivate/{random-uuid}/agent-card.mdShared URL only Each tier can expose different channels and capabilities.

Discovery Methods

Well-known URL: Check https://domain/.well-known/agent-card vCard extension: Look for X-AGENT-CARD field in contact cards Ask the human: Request the URL directly

Reading an Agent Card

When you fetch an agent card: Parse YAML frontmatter for structured data Read markdown body for natural language routing rules Choose appropriate channel based on your purpose Follow any authentication requirements mentioned

Test It

Here's a live demo you can test: https://city-services-api.dave-dean.workers.dev/.well-known/agent-card This is a fictional "City of Millbrook" tip line. Fetch the card, then try POSTing to the webhook endpoint. Your experience may vary depending on what you say.

Full Specification

See references/SPEC.md for the complete specification.

Examples

See references/EXAMPLES.md for more complete examples.