Skip to main content
The card command group provides functionality to retrieve agent cards and validate their structure and contents.

​
get

Retrieve an agent’s card, which contains metadata about the agent’s capabilities, description, and configuration. 
handler card get <agent_url> [OPTIONS]

​
Arguments

​
agent_url
string
required
URL of the A2A agent whose card to retrieve

​
Options

​
--authenticated
flag
Request authenticated extended card. Some agents may return additional information when authenticated. Short form: -a
Currently defined in the code but not fully implemented in the service layer.

​
Examples

handler card get http://localhost:8000

​
Response Format

The agent card is returned as JSON and includes:
  • name: Agent name
  • protocol_version: A2A protocol version
  • description: Human-readable description of the agent
  • url: Agent’s endpoint URL
  • capabilities: List of agent capabilities (e.g., streaming, push notifications)
  • models: Available models (if applicable)
  • authentication: Supported authentication methods
  • rate_limits: Rate limiting information (if applicable)
{
  "name": "Example Agent",
  "protocol_version": "2024-11-05",
  "description": "A helpful AI agent",
  "url": "http://localhost:8000",
  "capabilities": [
    "streaming",
    "push_notifications"
  ],
  "authentication": {
    "schemes": ["bearer", "api_key"]
  }
}
Agent cards are useful for discovering an agent’s capabilities before interacting with it. You can inspect the card to see what authentication methods are supported, whether streaming is available, and more.

​
validate

Validate an agent card from a URL or local file. Checks that the card conforms to the A2A protocol specification. 
handler card validate <source>

​
Arguments

​
source
string
required
URL or file path of the agent card to validate.
  • If the source starts with http:// or https://, it’s treated as a URL
  • Otherwise, it’s treated as a local file path

​
Examples

handler card validate http://localhost:8000

​
Response Format

​
Valid Card

When validation succeeds, the output includes:
  • Status: “Valid Agent Card”
  • Agent: Agent name from the card
  • Protocol Version: A2A protocol version
  • Source: URL or file path validated
Valid Agent Card
Agent: Example Agent
Protocol Version: 2024-11-05
Source: http://localhost:8000

​
Invalid Card

When validation fails, the output includes:
  • Status: “Invalid Agent Card”
  • Source: URL or file path validated
  • Errors: List of validation issues with field names and messages
Invalid Agent Card
Source: ./bad-card.json

Errors (2):
✗ name: Field required
✗ protocol_version: Invalid protocol version format
The command exits with status code 1 if validation fails.
Validation checks both the structure (required fields, types) and content (valid protocol versions, URLs, etc.) of the agent card.

​
Common Validation Issues

  • Missing required fields: name, protocol_version, url
  • Invalid protocol version: Must match supported A2A versions
  • Invalid URL format: Must be a valid HTTP/HTTPS URL
  • Invalid capability values: Must be from the defined set of capabilities
  • Malformed JSON: File must contain valid JSON
Use validation during development to ensure your agent card is correctly formatted before deploying your agent.