cardcheck

cardcheck tells you whether your agent should trust an A2A (Agent2Agent) peer, by checking its agent card.

vulkro-live cardcheck example.com
vulkro-live cardcheck https://agents.example.com/.well-known/agent-card.json
vulkro-live cardcheck --file ./agent-card.json   # nothing leaves the machine
cat card.json | vulkro-live cardcheck --file -

$ vulkro-live cardcheck --file ./agent-card.json

AVOID  (local card)
  identity  declared 'acme-support-agent' for https://agents.acme-corp.example/a2a
  signature absent
  provider  Acme Corp
  findings:
    HIGH   skills[0].description  the text contains an instruction-injection phrase: "ignore previous"
    HIGH   skills[0].description  the text contains an instruction-injection phrase: "do not mention"
    LOW    unsigned               card is unsigned: it cannot be cryptographically bound to its domain

An A2A agent publishes a card at /.well-known/agent-card.json. cardcheck fetches it (or reads a local file) and checks:

Identity: does the host that served the card match the origin it claims? A different domain is a HIGH impersonation signal.
Injection: every text field (name, description, skills), with warden's checks.
Look-alike names: mixed scripts or look-alike characters in the agent and provider names.
Capabilities and provider: informational.

cardcheck reports only whether a signature is present and well-formed. It does not verify signatures cryptographically and never says one is valid.

Flags

Flag	Effect
`[TARGET]`	A host, an https URL, or a full well-known card URL. Omit with `--file`
`--file <file>`	Read a local card instead of fetching; `-` reads stdin
`--no-cache`	Skip the local cache

Exit codes: 0 GREEN, 1 REVIEW or AVOID, 2 error. Output is text only (no --format).

Flags​

Flags