AgentMarque SDK

AgentMarque is a Python library for presenting and verifying W3C Verifiable Credentials for AI agents. Your agent receives a credential from the AgentMarque registry, presents it with holder binding and selective disclosure, and services verify both signatures -- all offline.

Two keys, two signatures

AgentMarque credentials separate issuer and holder signing:

• Issuer (AgentMarque registry) signs the credential with its key
• Holder (your agent) signs each presentation with its own key via a Key Binding JWT

Verifiers check both: the credential is from a trusted issuer, and the presenter controls the subject key. This prevents replay and impersonation -- a stolen credential is useless without the agent's private key.

1. Load a credential

Your agent receives a credential from the AgentMarque registry and stores it locally.

from agentmarque import AgentCredential

credential = AgentCredential.from_json(stored_credential_json)

2. Present with selective disclosure

Reveal only the claims a verifier needs. The holder's private key signs the KB-JWT.

presentation = credential.present(
    holder_key=my_private_key,
    verifier_nonce="nonce-from-hotel",
    audience="did:web:hotel-api.com",
    disclose=["verificationTier", "reputationScore", "organization"],
)

3. Verify

Check issuer signature, holder binding, nonce, audience, and policy -- in that order.

from agentmarque import AgentMarqueVerifier

verifier = AgentMarqueVerifier(trusted_issuers=["did:web:api.agentmarque.com"])
result = verifier.verify(
    presentation=presentation,
    expected_nonce="nonce-from-hotel",
    expected_audience="did:web:hotel-api.com",
    min_tier=2,
    min_reputation=60.0,
)
# result.valid, result.checks.holder_bound, result.claims["reputationScore"]

4. Handshake

Structured challenge-response wrapping the same holder-bound presentation flow.

from agentmarque import AgentHandshake

challenge = AgentHandshake.create_challenge(audience="did:web:hotel-api.com")
response = AgentHandshake.respond(challenge, credential, holder_key=my_private_key)
result = AgentHandshake.verify_response(response, challenge, verifier)