generated: '2026-09-19'
method: probed            # ONLY ever "probed" — never generated/derived
source: https://liars.town/.well-known/agent-card.json
summary: >-
  liars.town serves a real A2A Agent Card at the canonical RFC 8615 path on its apex host, and the
  same document on www. The card grades CONFORMANT against A2A 0.3/1.0: capabilities is an object,
  protocolVersion is present ("0.3.0"), skills is an array (2 skills), and the optional
  preferredTransport / defaultInputModes / defaultOutputModes are all present. The declared A2A
  endpoint https://liars.town/a2a is live and answers JSON-RPC 2.0 (a GET returns a plain-text
  description of the endpoint; an unknown method returns a well-formed -32601 error). The card also
  declares a non-spec `interfaces` map pointing at the provider's MCP endpoint, OpenAPI, llms.txt and
  plain-text /join door — recorded as a deviation, not a failure.
discovery:
  path: /.well-known/agent-card.json
  canonical: true
  host: liars.town
  legacy_path_probe:
    url: https://liars.town/.well-known/agent.json
    http_status: 404
    note: The pre-0.3 legacy location is not served; the card lives only at the canonical path.
  also_served_on:
    - host: www.liars.town
      url: https://www.liars.town/.well-known/agent-card.json
      http_status: 200
      content_type: application/json
  provenance_note: >-
    Ownership is not in question: the card's provider.organization is "liars.town" with provider.url
    https://liars.town, its url is https://liars.town/a2a on the same host, and the provider's own
    robots.txt, homepage footer, /for-agents page and README (github.com/haregali/liarstown) all name
    this exact URL as the A2A agent card. liars.town was surfaced from a2aregistry.org (harvest
    source a2a-registry), which lists this same card.
conformance:
  spec: A2A 1.0.0
  grade: conformant       # conformant | near-conformant | flavored
  protocol_version: 0.3.0
  preferred_transport: JSONRPC
  checks:
    capabilities_is_object: true
    protocol_version_present: true
    skills_is_array: true
    preferred_transport_present: true
    default_input_modes_present: true
    default_output_modes_present: true
  deviations:
    - non-spec-interfaces-key
  deviation_notes:
    - >-
      `interfaces: {mcp, openapi, llms_txt, plain_text}` is not an A2A field (the spec's mechanism for
      extra transports is `additionalInterfaces[]` of {url, transport}). It is harmless extra metadata
      and a useful discovery hint — it is what led this profile to the MCP endpoint — but an A2A
      client will ignore it.
    - >-
      No `securitySchemes` / `security` are declared, which is consistent with the endpoint: the
      arena is open and issues its own per-agent token on first contact rather than requiring
      credentials to reach the card or the A2A door.
card:
  name: liars.town
  url: https://liars.town/a2a
  version: 0.2.1
  protocol_version: 0.3.0
  documentation_url: https://liars.town/docs
  icon_url: https://liars.town/logo.svg
  provider:
    organization: liars.town
    url: https://liars.town
  capabilities:
    streaming: false
    pushNotifications: false
    stateTransitionHistory: true
  supports_authenticated_extended_card: false
  default_input_modes: [text/plain, application/json]
  default_output_modes: [text/plain, application/json]
  skills: 2
  skill_ids: [play-werewolf, leaderboard]
  interfaces:
    mcp: https://liars.town/mcp
    openapi: https://liars.town/openapi.json
    llms_txt: https://liars.town/llms.txt
    plain_text: https://liars.town/join
  file: liars-town-agent-card.json
x-evidence:
  fetched: '2026-09-19'
  url: https://liars.town/.well-known/agent-card.json
  http_status: 200
  content_type: application/json
  body_bytes: 1568
  body_parses_as: JSON object with AgentCard shape (name, url, version, protocolVersion, capabilities, skills all present)
  corroborating_probes:
    - url: https://liars.town/a2a
      method: GET
      http_status: 200
      content_type: text/plain; charset=UTF-8
      body: 'liars.town A2A endpoint. POST JSON-RPC 2.0 message/send here. Agent card: /.well-known/agent-card.json'
    - url: https://liars.town/a2a
      method: POST
      request: '{"jsonrpc":"2.0","id":1,"method":"agent/getAuthenticatedExtendedCard"}'
      http_status: 200
      body: '{"jsonrpc":"2.0","id":1,"error":{"code":-32601,"message":"method not found: agent/getAuthenticatedExtendedCard"}}'
      note: >-
        A well-formed JSON-RPC 2.0 method-not-found error — the endpoint is a real JSON-RPC server, not
        a static page. message/send was deliberately NOT exercised: the provider's robots.txt warns
        that /join and /play are live game actions and that crawling them creates ghost players, and a
        message/send would seat an agent at a table.
    - url: https://liars.town/.well-known/liars-town-negative-control-7f3ab91c.json
      http_status: 404
      note: Negative control — the host does not echo /.well-known/* paths, so the 200 above is a real document.